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FREQUENTLY ASKED QUESTIONS

Build-An-Adapter usage

Q. What is Build-an-Adapter?

A. Build-an-Adapter is an online application enabling astronomers to design custom connections between any two devices in just a few clicks. Using the application is easy: just select the devices to connect on each side, observing the left-to-right direction of light, and specify the length of the connection.
For a complete example please check this video tutorial on

It is important to realize that Build-an-Adapter IS NOT an adapter catalog. We machine custom parts designed and ordered online by customers, exclusively. PreciseParts is not a general machine shop in any sense of the term. We are not able to design adapters nor do we sell off-the-shelf parts.
We work most often with professional astronomers and high-end amateurs, but anyone is welcome to take advantage of our online application to design custom astro-photography adapters, although to prevent misunderstandings and costly mistakes we strongly recommend carefully reading the instructions in this section BEFORE designing and ordering parts on our site. Please consider that we are not able to refund a custom adapter ordered for the wrong devices or at the wrong length.

Q. What do I need to know to design a custom adapter on your site?

A. Our customers like to call Build-An-Adapter a "Computer Aided Design (CAD) for Astronomers" but no special skills are actually required to create adapters on our site, nor does one needs to know the connection or thread specifications for any of the astronomical devices listed on our site.
However, to use our web app effectively, one should be familiar with the function of each device in the optical train and with the basic physical and optical properties of the equipment to be connected. These characteristics include how each device connects and its respective back-focus. In addition, if the adapter, or adapters, are to integrate the components of an imaging train it is important to know the location of the system focal plane, the recommended distances, the clear aperture and the focal ratio of the optical system. These are often critical pieces of information to create appropriate adapters for a custom astrophotography setup.
If unfamiliar with the terminology or unsure about back-focus or focal distances for a particular device we strongly recommend consulting the respective manufacturers or a reputable telescope dealer for recommendations and assistance prior to designing adapters on our site.
Please consider that we custom machine each part as ordered therefore an adapter ordered at the wrong length or for the wrong device cannot be returned.

Q. How do I specify a custom adapter with Build-An-Adapter?

A. First only consider the devices the adapter will directly connect to. For example, if you need an adapter between a reducer and a filter wheel, you want to select the reducer on the scope side and the filter wheel on the camera side. The sides are always relative to the point of view of the adapter itself. It matters little what the particular telescope and camera are in this case, but observe that the DIRECTION OF LIGHT is indicated on the page by a red arrow and the light ALWAYS travels left to right in our application. This rule must be strictly adhered to. Inverting the light direction will result in an adapter with incorrect genders or features.
Proceeding with our example, first you want to select on the left side the manufacturer of the reducer, for example Optec, and on the right side the brand name of the filter wheel, for example Finger Lakes then click Next to select the specific devices to connect left and right, for example Optec Lepus and FLI CFW-3 Series respectively, and finally typing in the center field the effective length required for this particular adapter, in either inch or mm. In many situations the length can be typed as 0 (zero) to produce as short a connection as is mechanically possible. Please note however that a minimum length adapter is not always desirable and you want to check this answer if a specific effective length is required and you need assistance to calculate the length.
The custom adapter design is displayed on the page as soon as the Build button is clicked. The price is informed in the right pane.
The adapter designed can be viewed and rendered in 3-D with a recent browser, then finally, if the design matches what is expected, the part can be ordered online via the Add-to-Cart button at the bottom of the page.

Q. I tried to use Build-An-Adapter but nothing happens when I click "Next"

A. Please verify your browser configuration to ensure JavaScript is enabled. JavaScript is required to use Build-An-Adapter. Check under Preferences, Options, or Settings for your particular browser.
To display the adapter design, your browser must also recognize HTML5 (aka Mozilla/5.x). All current versions of Firefox, Safari, Google Chrome, and Opera support HTML5, including the browsers available on most mobile devices such as iPhone, Android, Blackberry or iPad. Internet Explorer supports HTML5 starting with version 10. Please check this answer for more information.
Rendering the adapter in Virtual Reality 3-D requires a browser compatible with WebGL. While most newer browsers supports WebGL by default, some browsers such as Safari on macOS require WebGL to be explicitly enabled. If you are using Safari please check this answer for assistance.

Q. I cannot find my device in the listings

A. If your astronomical device is not listed under a brand name, it might be available under the generic devices category located at the end of the pull-down menus on the first page.
It is important to note that the selections listed represent the device or feature the adapter SHOULD CONNECT TO, rather than the feature required on the adapter itself. For example, if you need an adapter with a nosepiece you must select the device that nosepiece will CONNECT TO, generally a 1.25 or 2 inch adapter/focuser on the telescope side. These entries can be found either under a specific brand name or under "generic devices". Conversely, a 1.25 or 2 inch receptacle can be created by selecting a matching nosepiece on the camera side.
Please note that, to prevent cluttering our brand menus we purposely do not list brand name devices featuring industry standard connections, such as 1.25 or 2 inch eyepiece style slip-fit connections, or common size threads such as T-thread or T2 since these features can be found under our "generic devices" category.
However if your device is not listed under any of the pull-down menus and does not match a generic feature either, please email us a detailed description, including make and model number. We will then gladly add your device to our database if the connection specifications can be located.


Q. My device brand name is not in the list.

A. If your astronomical device brand name is missing from the brand name menus, it might be listed under other brand names. This selection is located at the end of the pull-down menus on the first page.


Q. Is there a cost to design a custom adapter online?

A. Any number of parts can be designed online with Build-An-Adapter and the service is completely free.
We even encourage our users to click the Build button repeatedely to create parts with various effective lengths or features as this can be very useful for trying different setups.
You only pay when parts are placed in the Shopping Cart and the order is accepted by our payment processor (currently PayPal).

Q. Do you have off-the-shelf parts available for quick shipment?

A. No, we do not keep an inventory of parts. All the adapters we make are designed online by our customers with the features and length selected to specifically fit a particular application. We then custom machine the part as ordered.
If you urgently require a custom adapter to complete your image train, we suggest checking this answer

Q. I have a drawing or thread dimensions for the part I need. Can you can make an adapter based on this information?

A. No. Our systems are largely automated and we only make adapters to connect actual devices for which we have complete thread specifications on file.
We cannot make a part based solely on a customer supplied drawing or thread measurements.
We recommend first exploring the full list of devices available in Build-An-Adapter. Our database is very comprehensive and encompasses the vast majority of astronomical devices, past and present.
Please be sure to also check the other brand names category, and lastly the generic devices category. Both categories are located at the end of the drop down menus on the first page.
Our search tool can also be used to locate a particular device by typing one or two keywords in the search field (at the top of every page on our site.) Do not enter a long description in the field as this will most likely prevent the search engine from finding any match.
If your particular device happens not to be listed at all please let us know and we will be happy to add it to our database if connecting information is available and is within our machining capacity.
But if none of these options would work we suggest contacting a general machine shop to make the part you need.

Q. I built a custom adapter on your site. Can you tell me what the thread size is?

A. Regrettabley we do not provide information on thread size (or other features size), however if you are positive the correct devices were selected to build the adapter we can guarantee the custom adapter will fit. If the adapter does not fit the selected device(s) we will either correct or redo the part at no additional cost.

Q. Can you make adapter pieces for mounts, tripods, or piers?

A. No. We only make parts and adapters for optical trains, and for the devices listed in our Build-an-Adapter web app.

Q. My local language is not one of the languages available in Build-an-Adapter. Can I use a translation service offered by my browser?

A. Unfortunately not as our application dynamically creates a custom environment based on the initial selections and this is generally not supported by a browser translation service. This situation will usually cause a "missing information" error.
If you native language is not one of the language we support and you are unable to design the part you need, please contact us directly.

Adapter Effective Length

Q. What is effective length?

A. An adapter's Effective Length is defined as the distance the adapter adds to the optical path, or equivalently, the back-focus the adapter consumes from the image train.
This distance value is also called Optical Length.
To verify where the effective length of a particular adapter is measured please refer to the 2-D drawing displayed on the Build page lower left pane; the thin red lines in the graphics show where the effective length is measured from.

Q. Does effective length include threads?

A. One of the benefit of using Build-An-Adapter is there is no need to consider threads or other connection features to calculate a custom adapter effective length. Build-An-Adapter does take care of these details and creates a part with appropriate dimensions such that the finished adapter optical length ends up exactly as specified. The 2D adapter drawing displayed on the Build page shows precisely where the adapter effective length is measured from.
If one wishes to dig deeper into the matter, here are the ugly details: conventional male features (typically threads) do not contribute to effective length while conventional female features are an integral part of the effective length.
But unfortunately there are exceptions to this seemingly simple rule, most notably for SCT rear cells which present a male thread to mount a visual back or an imaging system. The length of this SCT thread is NOT included in the length of any adapter designed for one of these telescope rear cell. Or in other words, the back-focus on a SCT is always measured from the TOP of the male thread at the rear of the scope. This is the reference point SCT manufacturers use to measure focal distance. The above rule is also applicable to Meade ACF and Celestron EdgeHD instruments, as well as a few other, less common, optical devices. Although this is clearly not the conventional way to measure back-focus, Build-An-Adapter is smart enough to take these peculiarities into account when calculating an adapter actual length, so you do not need to.
The bottom line is that ONLY the desired NET adapter optical length needs to be specified in Build-An-Adapter. This is precisely the definition of the term Effective Length.

Q. How can I figure out the adapter length required?

A. The Adapter Effective Length is the net distance the custom adapter will add to the optical path.
(If you are designing a SLR or DSLR lens adapter for an astronomical camera, please check this answer.)
If you need an adapter consuming the minimum possible amount of back focus, just enter 0 for the Adapter Effective Length to let Build-An-Adapter calculate the shortest possible adapter that will connect the devices selected. The actual, calculated, length will be displayed in the length field after the Build button is clicked. The length is displayed in inch or mm according to the unit selected. The calculated value may or may not actually be zero; the minimum length is constrained by the specific mechanical features required for this particular adapter.
Always check the 2D drawing displayed on the Build page for a visual confirmation of how the effective length is measured.
For a practical example how to calculate an adapter length please check this video.

Noting that a custom adapter designed at minimum length may not be adequate for a photographic lens, or for the camera side of a field flattener or reducer: to reach focus or achieve a flat image field, a flattener, reducer, or lens must be located at a precise Optical Distance in front of the camera sensor.
The recommended Optical Distance for a reducer/flattener is also known as the Metal Back Distance and the value is generally supplied by the device manufacturer.
To determine the Adapter Effective Length for such optical system, the Image Train Back Focus needs to be calculated precisely and subtracted from this Optical Distance, thus:
  • Adapter Effective Length = Optical Distance - Image Train Back focus
In the simplest example, if we have a flattener requiring an Optical Distance of 55 mm and we want to connect a camera having 17.5 mm of back-focus to that flattener, the Image Train Back Focus is simply 17.5 mm and we will need a custom adapter with an Effective Length of 37.5 mm (55 minus 17.5) to end up with the correct spacing for the flattener.
This example, although simple, is not very realistic as image trains generally incorporate several different accessories inserted in front of the camera. Here is a more complete example:

We have a reducer requiring 86 mm of Optical distance, and we have both a filter wheel and an off-axis guider inserted in the image train between the reducer and the camera. Such devices clearly consume back focus so the thickness of ALL these accessories must be taken into account in calculations. The Image Train Back focus is then the sum of these components thicknesses and back-focus, then as before we use the formula above and subtract the total Image Train Back focus from our Optical Distance.
For the example shown in the drawing we end up with an Image Train Back focus of 39.5 mm (10 + 12 + 17.5) and consequently the adapter effective length will need to be 86 mm minus 39.5 mm, or 46.5 mm.
Additionally, if there is any glass filter installed between the reducer/flattener and the camera (eg. in the filter wheel), the effective length may need a small correction to take into account light diffraction through the filter glass: each 3 mm of glass thickness INCREASES the Optical Distance by about 1 mm and the correction must be ADDED in the formula, therefore increasing the Adapter Effective Length by the same amount to compensate for the glass correction.
In our example image train above, if our filter wheel is equipped with 3 mm thick glass filters, our corrected Adapter Effective Length is now 47.5 mm (86 minus 39.5 PLUS 1 mm for the filter correction).

Q. Build-An-Adapter says my adapter is too long.

A. Generally, a custom adapter should be less than 3 inches (75 mm) in effective length. If the particular application requires a longer adapter to reach a specific distance, we recommend inserting additional components in the optical path, such as as off-the-shelf extension tubes, to shorten the gap a custom adapter needs to bridge. Please also consider that the price of a custom adapter rises VERY rapidly as the length increases. The vast majority of custom adapters we make are less than 1.5 inch (40 mm) in length.

Q. Can you verify whether the length I am ordering is accurate?

A. We are generally not able to. An adapter effective length is normally a function of the devices optical lengths and/or back-focus distances and PreciseParts is not the authority on these figures. If any concern or doubts about these values please always double-check with the device manufacturer.
We do offer comprehensive guidelines to help calculate a custom adapter length. Please check this answer.
Disclaimer: Please be aware that the adapter length ordered is ultimately the customer responsibility and we cannot be held liable for an adapter length that ends up inappropriate for a particular application.

Q. Will the adapter be strong enough if I select the minimum length?

A. An adapter strength bears little relation to its length. All our custom adapters are automatically designed with enough metal thickness to support the loads the connected devices are designed for, and to provide the needed rigidity for such applications.

Q. Can Build-An-Adapter automatically calculate the correct length for my adapter?

A. Build-An-Adapter does not have enough information to accurately determine the length. The only exception is for minimum length when Build-An-Adapter automatically calculates the shortest possible adapter when 0 is typed in the length field (noting that 0 is not an acceptable value for a DSLR lens adapter - check this answer). A minimum length adapter however may not be adequate for a particular application and it is critical to be fully familiar with the characteristics of one's optical setup to be able to determine an appropriate length for the adapter.

Q. Why cannot I specify a shorter length if the graphics seems to show it's possible?

A. Build-An-Adapter automatically calculates the shortest possible length for a custom adapter if 0 is typed in the effective length field. If the actual, calculated, effective length seems overly large, the device to be connected most likely requires some kind of clearance to prevent obstructing or interfering with device features. This clearance requirement would thus prevent the adapter to be made shorter. The clearance should be displayed on the graphics, and is usually best visualized on the adapter 3-D rendering, as a step or shoulder machined at the maximum outer diameter (or minimum inner diameter) which would still clear the particular device feature.
You want to check whether the device offers some alternative compatible connections to work around the clearance requirement. If not sure we recommend verifying with the respective device manufacturer whether an alternative connection is possible.

Q. Can I request a change in effective length after I placed an order?

A. Unfortunately we are not able to change the specifications of a custom adapter after an order in transmitted as our production systems are fully automated.
If the adapter length ordered was incorrect we recommend contacting us as soon as possible. The easiest and fastest way is to simply reply to our order confirmation email, but emailing us indicating the order reference number (aka invoice number in PayPal) is also acceptable. We may then be able to cancel the order if the part fabrication has not yet started. Please check this answer to verify the conditions for an order cancellation.

Q. The red reference lines where the effective length is measured seem to be at the wrong place in the drawing?

A. The vertical lines indicating the adapter effective length may appear shifted left or right under rare circumstances, however rest assured that the effective length value displayed is correct and its accuracy is not affected.
The issue is caused by a graphics artifact that might sometimes show up when the effective length is based on a non-standard reference point, such as adapters for SCT-type rear cells.

Error Messages

Q. I get an error message when I press Build

A. Please verify that both sides have devices selected and that a length value is entered, noting that zero can be used as the length in most cases to achieve the shortest possible path length compatible with the connections selected.
If all fields have a selection but an error is still displayed, we generally provide detailed information spelling out the cause of the error together with some possible alternatives. Please read the entire message. Our application not only examines the required connections but also evaluates whether it is mechanically possible to make the desired part with our CNC equipment.
If this is still not clear please contact us with the error message number shown in brackets and a description of the adapter you are trying to design.
Please be aware that Build-An-Adapter may sometimes be unable to create the desired part due to certain types of mechanical constraints such as the ones described in this answer.

Q. Build-An-Adapter says the length I entered is not sufficient to make the part.

A. All adapters need a certain minimum effective length so they can be built. The minimum length essentially depends on the features required to make the desired connection, including any prescribed clearance mandated by a particular device.
The minimum length is automatically calculated if 0 is entered in the Effective Length field. The adapter will then be made with the the shortest possible effective, or path, length. The actual, calculated, minimum length value is displayed in the Effective Length field, in either inch or mm based on the unit selected. This calculated value can be useful to subsequently determine the total optical length of an image train.
If the adapter length seems to be overly large for the type of connection, you want to double-check whether one of the devices requires a special clearance to either (a) prevent mechanical interference with some protruding feature - a common issue with off-axis guiders, or (b) provide room to access adjustment screws - frequently found on certain recent astronomy camera models.
Note: Build-An-Adapter is not able to calculate a minimum length for a lens adapter. Check this answer if you are designing a custom adapter for a SLR/DSLR camera lens.

Q. Build-An-Adapter says the adapter "is not possible" or "cannot be built".

A. Certain custom adapters cannot be created as a single piece. Typically custom adapters requiring a bolted flange at both ends are not possible.
Also, if an adapter is bolted at one end the feature at the other end cannot have a diameter value too close to the diameter of the bolt circle since this would prevent drilling the holes or installing the screws; in both case a possible solution is to select a non-bolted option, if available for the selected device.
There are also other constraints when building a SLR/DSLR lens adapter for an astronomical camera. Please see this answer if you get an error when attempting to design this kind of adapter.

Q. Build-An-Adapter says "An extension tube for this feature is not available".

A. An extension tube requires a pair of complementary features, for example a male thread and its matching female. However sometimes we do not have specifications in our database for one of the feature or the device selected requires special clearance which would make an extension tube impractical for this particular connection since we cannot guarantee an extension tube can provide the necessary clearance.

Q. Build-An-Adapter says my adapter is too long

A. Generally, a custom adapter should be less than 3 inches (75 mm) in effective length. If the particular application requires a longer adapter to reach a specific distance, we recommend inserting additional components, such as a standard extension tube, in the optical path to shorten the gap the custom adapter will need to bridge. Please also consider that the price of a custom adapter rises very rapidly as the length increases. The vast majority of custom adapters we make are less than 1 inch.

Q. I get errors stating that BUILD was double-clicked, or I just get a blank page when trying to build a part

A. Please be sure to click the Build, or Build Again, button just once but if the error persists the problem is probably with the browser. Certain versions of Internet Explorer and Edge, in particular IE rev 11.0 and all versions of Edge, generate a double-click by themselves when any action button is single clicked.
Unfortunately there is no easy work-around for this issue and we recommend using another browser to access our site until the IE/Edge issue is fixed.

Q. I get an error stating that a washer cannot be made for the device or feature I selected

A. A washer can be created for most standard male threads, as well as some other male features, however a washer would not be useful for male threads having non-standard reference points as in such cases a washer would not have any solid surface to lie against. This holds true for threads at the back of SCT or ACF/EdgeHD telescopes. In this case the matching FEMALE thread should be selected on the other side. For axample, for a SCT/EdgeHD, a SCT or EdgeHD accessory can be selected on the Camera Side if one wishes to design an appropriately sized washer to drop INSIDE that female thread and provides the desired spacing.
Noting that it is critical to make the washer short enough so it does not overrun the thread, otherwise the washer may prevent the thread from engaging. Check this answer for instructions about designing a washer.

Questions about Devices

Q. I have a technical question about a particular device. Can you help?

A. Unfortunately we are not able to assist with device questions. Our familiarity with astronomy equipments is generally limited to their mechanical connectivity. We recommend consulting the manufacturer or an astronomy dealer for detailed information about a particular device.

Q. My particular device is not listed in Build-An-Adapter

A. Please be sure to check the full list of devices available in Build-An-Adapter. First search under the device brand name, then if the name is not listed, check the other brand names category located at the end of the drop down menus on the first page. The other brand names category lists less common names and devices.
The search field, available at the top of every page on our site, is usually helpful to locate a particular device as search results will generally show under what brand name or category it is listed.
Lastly, if you believe your device uses an industry standard thread or feature, this may be listed under "generic devices", but please also check this answer.
It is important to note that the selections listed represent the device or feature the adapter SHOULD CONNECT TO, rather than the feature required on the adapter itself. For example, if you need an adapter with a nosepiece you must select the device the nosepiece will CONNECT TO, generally a 1.25 or 2 inch adapter/focuser on the telescope side. These entries can be found either under a brand name or under "generic devices". Conversely, a 1.25 or 2 inch receptacle can be created by selecting a matching nosepiece on the camera side.
Our database is very comprehensive and encompasses the vast majority of astronomical devices, past and present, but if after exploring all the suggestions above you still cannot find your particular device in the lists please contact us with a detailed description, including the make and model number. We will gladly add your device to the database if the connection specifications are available.
Alternatively, if you know or can measure threads or other connecting features on the device, we might be able to add an entry in Build-An-Adapter based on that information together with the complete name and description, including well focused pictures of the device.

Q. My device seems to match several possible selections. Which one do I chose?

A. First be sure to select the exact device rather than a generic feature. It is always safer to select the brand name device if that device is listed (check this answer for further details).
Many devices have similar designations, but sometimes different connection methods. We generally list the 'naked' device (eg. without any adapter installed) unless the device REQUIRES an adapter to be fully functional, then we normally list the available connection options. Selecting the correct device or connection option is very important. If any doubt it is best to double-check with the device manufacturer or your dealer.
Regarding device designations in our pull-down menus: we always try to describe devices using the same terminology as the manufacturer thus please consult the device manufacturer or your dealer if you are not sure how the device is called. Some manufacturers, such as Takahashi, provide detailed system charts with precise component designations, and we strongly recommend checking your particular telescope system chart in case of doubt.
If your device is listed with several connection options, such as bolted or threaded, and you have the device in hands, you want to visually examine the device to verify the type of connection it came with, noting that the terms "bolted" and "threaded" refer to the way a custom adapter is installed on the device.
A number of astronomical cameras and accessories are supplied with various optional faceplates or mounting hardware to accommodate several different installation methods. Other cameras come standard with various mounting options, and the most appropriate connection will depend on the particular imaging setup. While most mounting alternatives should provide adequate connections, some connection methods have limitations or restrictions. For example, if available, a dovetail connection is usually preferable to a bolted or threaded connection since the former allows angular adjustment of the image train, however if the telescope offers other means of rotating the imager a bolted connection, when mechanically possible, may be more rigid and usually consumes less back-focus. A threaded connection on the other hand will generally produce the least costly custom adapter if the device offers that option.

Q. How can I be sure a custom adapter will fit my devices?

A. We stand behind our design and will promptly replace or rework a custom adapter if it does not fit either device, or if the part length does not match the effective length ordered, within a reasonable tolerance. Please also check our warranty statement here.

Q. Can Build-An-Adapter check whether I am ordering the correct adapter for my devices?

A. The Adapter Builder generally does not have enough information to verify the suitability of an adapter for a particular application, however we do guarantee our adapters will fit the devices selected. We also generally review orders and may be able to flag some potential inconsistencies, and we may contact you in such situation but please be aware that we are not equipment specialists therefore our knowledge of astronomical equipment is necessarily limited. We recommend to proactively contact us if any doubt or concern about the adapter design, noting that the vast majority of connecting issues can be prevented by simply examining the adapter drawings on our site (both 2-D and 3-D rendering) before placing an order.

Q. The feature I want to connect is an industry standard. What brand name do I select?

A. Most industry standard, non brand name, connections can be found under the generic devices category located at the end of the pull-down menus on the first page.
Please note however that we do not recommend selecting the generic version if your device is listed under a brand name. If a generic thread is selected instead of the actual device, you order at your own risk as we are not able to guarantee the adapter will fit under all circumstances. Most manufacturers use some proprietary variations in thread specifications and we can only abide by these special measurements if we know the exact device the custom adapter is intended for.

Q. I know my device has a standard thread, can't I just select a generic version?

A. We do not recommend selecting a generic thread if the device to be connected is listed in Build-An-Adapter under a brand name. If a generic thread is selected instead of the actual device you order at your own risk as we are not able to guarantee the adapter will fit under all circumstances. Also, many devices have standard threads but require adapters with special morphology to prevent mechanical interferences. Manufacturers may use proprietary variations in thread specifications and we can only abide by these special dimensions if we know the exact device the custom adapter is intended for.

Q. I have a drawing or thread dimensions for the part I need. Can you can make an adapter based on this information?

A. No. Our systems are largely automated and we only make adapters to connect actual devices for which we have complete thread specifications on file.
We cannot make a part based solely on a customer supplied drawing or thread measurements.
We recommend first exploring the full list of devices available in Build-An-Adapter. Our database is very comprehensive and encompasses the vast majority of astronomical devices, past and present.
Please be sure to also check the other brand names category, and lastly the generic devices category. Both categories are located at the end of the drop down menus on the first page.
Our search tool can also be used to locate a particular device by typing one or two keywords in the search field (at the top of every page on our site.) Do not enter a long description in the field as this will most likely prevent the search engine from finding any match.
If your particular device happens not to be listed at all please let us know and we will be happy to add it to our database if connecting information is available and is within our machining capacity.
But if none of these options would work we suggest contacting a general machine shop to make the part you need.

Q. I need an adapter to mount a SLR/DSLR lens on my astro camera.

A. Build-An-Adapter can create lens adapters for some common SLR or DSLR photographic lenses but please be aware that there are severe constraints in designing a lens adapter for astronomical photography and the instructions below must be followed exactly to produce a custom adapter that will work for this application.
The adapter effective length is critical to preserve the lens infinity focus when installed on an astronomical camera therefore the lens being considered must have a large enough Focal Distance to allow an adapter to be made. A custom adapter can only be fabricated if the lens Focal Distance is substantially larger than the camera or image train back-focus. This condition generally precludes using newer MIRRORLESS camera lenses for this application as these lenses usually have a very short Focal Distance.
The adapter exact effective length can be calculated by subtracting the astronomical camera back-focus (including any installed accessory) from the lens Focal Distance.
  • Adapter Effective Length = Focal Distance - Camera Back focus
The lens Focal Distance (aka Registration Distance) is a fixed value, generally specified in mm. This Focal Distance is the same for ALL the lenses in a particular family, for example the Canon EF family features a Focal Distance of 44 mm. Noting that the Focal Distance is NOT RELATED to the lens focal length. A particular lens family Focal Distance can be displayed in Build-An-Adapter by selecting that lens on the left side and the desired camera on the right side, and then simply specifying 0 for the adapter length. This causes a pop-up error but the message also informs the lens Focal Distance.
If the camera is the only component in the image train, the Camera Back Focus is simply the internal back-focus of the astronomical camera as quoted by its manufacturer or informed in the documentation.
Once both the lens Focal Distance and the camera, or image train, back-focus have been determined, the simple subtraction above is all that is needed to determine the adapter effective length.
(Please check this answer if you need help calculating your Image Train Back Focus.)
For example if the lens focal distance is 85 mm and the image train back-focus is 38 mm, the nominal effective length for the lens adapter will be 47 mm (85 minus 38). For safety we recommend shortening this length a little (the exact amount is lens dependent but 0.5 to 1 mm is generally adequate) therefore a safer effective length would be 46 mm for this particular example. Note however that a lens adapter cannot be shorter than a certain minimum since we do need some room for the adapter body itself. The minimum value depends on the selected lens type and on the device the lens is to be used with.
If these instructions are followed precisely and Build-An-Adapter issues a pop-up window stating that either the length entered is insufficient, or too large to preserve infinity focus, an adapter for this combination of lens and camera is probably not possible.
Please note that 3-D rendering is not available for a lens adapter. The 2D drawing however is rendered correctly, including markings showing where the adapter effective length is measured from.
Important: lens control functions, such as aperture and focus, are not available in lens adapters designed for astronomical cameras. Manual lenses are generally recommended for these applications.

Q. How can I mount a SLR or DSLR camera on my telescope gear?

A. A custom adapter is not normally needed to mount a DSLR camera on a telescope. Mounting this type of camera is best accomplished with a standard adapter known as a T-Ring, aka T-Mount, that is simply screwed on the standard photo adapter supplied with most telescopes.
T-Rings are available to fit practically all brands and models of 35 mm DSLR as well as some medium format DSLRs. Also, several telescope manufacturers such as Astro-Physics and TeleVue provide off-the-shelf medium format camera adapters.
T-Rings for DSLR can be purchased at most camera and telescope dealers for a few dollars. Although T-rings for newer mirrorless cameras are somewhat less common, an appropriate T-ring can generally be located by searching the web with keywords 't-ring mirrorless'.
If your telescope did not come with the male t-threaded or M48 photo adapter needed to install the T-Ring (this is rare) then a custom adapter between the telescope and the T-Ring can be created in a few clicks in Build-An-Adapter: Just select the last device before the camera in your image train on the Telescope Side, and DSLR T-Mount/T-Ring or DSLR Wide T-Mount on the Camera Side. These connections are available either under the DLSR camera brand name or under Generic Devices if the specific camera brand is not listed.
Note that a 35 mm format DSLR camera equipped with a T-Ring ALWAYS has a back-focus of 55 to 56 mm. Check this answer if you are not sure how long an adapter for your T-Ring needs to be.

Q. Can you make adapters for solar filters?

A. We can make custom adapters for a variety of solar filters if the telescope features a threaded lens cell or a threaded dewshield, and we have the manufacturer's information listed in Build-an-Adapter.
You want to select the solar filter on the TELESCOPE side and the telescope objective or dewshield on the CAMERA side. Although this seems counterintuitive these selections do respect the left-to-right "direction of light" rule used throughout the Build-An-Adapter application.
A solar filter adapter can generally be designed at minimum length. Typing 0 in the length field will produce the shortest possible adapter.
Please note that in the interest of safety and cost, we DO NOT make so-called slip fit multi-thumbscrews adapters some manufacturers use to install solar filters over unthreaded dewshields.
Most telescope lens cells are threaded although sometimes a "beauty ring" must be removed to expose the thread. We have specifications on file for many telescope lens cells but if your particular instrument has a threaded cell and is not listed in Build-An-Adapter on the CAMERA side please let us know and we can try to obtain appropriate specifications to add the lens cell in our database for online access.

Q. My device requires clearance to prevent interference. Does Build-An-Adapter take this type of requirement into consideration?

A. We are aware that a number of devices, such as some cameras and guiders, have irregular or non-flat mounting surfaces and may have a section of housing, a guide port and/or associated helical focuser that can potentially prevent installing an adapter unless the adapter provides special clearance.
Build-An-Adapter takes the needed clearance into account automatically for most known potential interferences and the clearance is usually reflected in the 2-D drawing or 3-D rendering displayed online.
However if adapter interference is suspected for a particular device and no clearance is shown in the drawings we recommend confirming with us prior to ordering. In particular, some Innovations Foresight devices, such as ONAGs, do require clearance in some cases, but our system is not able to predict when this might occur thus we recommend consulting Innovations Foresight's ONAG page on their site for instructions and notify us after placing an order for an IFI ONAG adapter if a clearance issue is expected.
Please note that AUTOMATIC clearance can only be provided for the devices the adapter is DIRECTLY connected to, and this specifically excludes secondary clearance issues where some accessory might produce interference when mounted on a particular device, or when two devices end up too close. It is the user responsibility to ensure that the devices to be assembled in a particular setup do not interfere with each others, or if they do to notify us of the need for clearance.

Q. My device requires a special thread. Does Build-An-Adapter takes this into account?

A. We have detailed specifications in our database on all devices listed in Build-An-Adapter. These specifications include the exact thread morphology required for each device.
For examples some devices require threads machined shorter than normal to prevent interfering with internal mechanisms, while others require longer male threads to reach a recessed internal thread present on some devices. We take these particularities into account when making adapters for such devices.

Q. My device comes with several adapters but not all these options are listed in your app.

A. As a general rule we only list "native" device connection(s) to prevent clutter and confusion. If other connection alternatives are supplied by the device manufacturer these connections are usually industry standard and most probably listed under the "generic devices" category.

Q. Can you modify an existing adapter or device?

A. Unfortunately no. If a device or adapter requires change to fit a different connection, we recommend designing an ad hok adapter online to make the existing device or adapter compatible with the new connection, if at all possible.

Q. I need a custom adapter to connect to an existing adapter. Can you provide that?

A. As a general rule, with very few exceptions we do not make adapters for adapters, however it may be possible to find an entry in Build-an-Adapter matching the required feature, or preferably, matching the actual device the existing adapter was originally intended for. As an example, if the purpose of the existing adapter is to provide an alternate connection type for a device's camera side, then the prefered solution is to create a DIRECT custom adapter for the device itself thus completely bypassing the existing adapter; this is normally the best alternative since it eliminates a component from the image train, an outcome that is almost always desirable.

Q. Can you make an adapter to use a mirrorless camera lens on my astro CCD camera?

A. Unfortunately not as these lenses normally have a very short Focal Distance, and do not provide the needed room to add a custom adapter.
Generally, the lenses we can make adapters for are listed in our web app under their respective brand names.
Also check this answer for further details.


Other Features

Q. Can you make a dust cap or plug to fit my device?

A. A dust cap can be created for almost any device or feature. First select Dust Cap on the side the dust cap should be installed, then select the device to plug on the other side. The "dust cap" selection is located at the end of the pull-down menus on the first page.
For example if you need a dust cap for your camera you want to select the specific camera on the Camera Side and Dust Cap on the Telescope side, but if you need to cap the device WHERE THE CAMERA IS CONNECTED you must select THAT device on the Telescope Side.
There is generally no need to specify a length for a dust cap since Effective Length has no meaning for a cap so the value is defaulted to 0 (zero) to produce the shortest possible dust cap compatible with the device. This length is generally perfectly adequate while minimizing part cost.
Please note that while all custom adapters are made from aluminum, we custom machine dust caps from black Acetal (aka. Delrin), a tough engineering plastic that looks like black anodized aluminum and matches the appearance of most telescope accessories while ensuring a tight seal.

Q. I just need an extension tube. How do I specify that?

A. First select the device or feature the extension tube should connect to, on the Telescope side or on the Camera side, observing the direction of light, then select extensions and spacers -> Extension Tube on the other side.
The "extensions and spacers" category is located at the end of the pull-down menus on the first page.
Note that we define "extension tube" as a connector with opposite genders at each end. For example a threaded extension tube has a male thread at one end and the matching female thread at the other end.
Most, but not all, kinds of extension can be designed online.

Q. Can you add a provision to install a filter inside the adapter?

A. We can generally add an internal thread in a custom adapter designed online. A common purpose is to mount a filter but the extra thread can have other use, such as installing a corrector inside the custom adapter. It is important to note that the adapter must be large enough to have room for the internally mounted device.
In most cases there is an extra charge for adding the internal thread. This charge is billed separately via PayPal after we receive your order.
Please follow these special instructions to provision for an extra female thread:
First place an order for the adapter with the needed connections on both sides, then add a note on the payment page under "Add instructions to seller", also indicating the filter thread size. But if an appropriate field is not available on the payment page, please email us the same information together with the order reference number (the easiest and quickest way to place the request is to reply to our order confirmation email).
A filter add-on is normally provisioned on the camera side, except for a nosepiece where a filter thread is machined in the conventional location, but if the filter thread needs to be added at a specific location then you want to supply that information as well.

Provisioning for an UNMOUNTED filter can be requested in the same manner but requires ordering an extra retaining ring to hold the filter. An appropriate retaining ring is easily created by selecting lock/retaining ring (under extensions and spacers) on the SCOPE side and a filter (under generic devices) on the CAMERA side. The filter selected should have approximately the same diameter as the unmounted filter but does not need to be an exact match. We can make the necessary adjustment assuming the exact DIAMETER and THICKNESS of the unmounted filter is supplied when requesting this feature.

Q. I need a lock ring or retaining ring. How do I specify that?

A. A Lock Ring is a female threaded ring to be inserted between two devices to secure the devices at a certain distance or at a certain angle, while a Retaining Ring is a male threaded ring used for example to secure a lens within a cell or within a filter frame.
To create either part, first select the device or feature the ring will connect to, on the Telescope or the Camera side (the side selected will usually dictate whether the ring is threaded female, a lock ring, or male, a retaining ring, based on the selected device gender), then select extensions and spacers -> Lock Ring on the other side. Noting that the "extensions and spacers" category is located at the end of the pull-down menus on the first page.
For examples selecting a generic T-thread on the Telescope Side produces a female threaded lock ring, while a male threaded retaining ring can be created by selecting a generic filter on the Camera Side. Again, the selection on the other side should be extensions and spacers -> Lock Ring.
Our Virtual Reality 3-D rendering is best to show details in thin parts such as lock rings and retaining rings. Zoom the display by scrolling or pinching.
Lock rings and retaining rings are usually made at minimum length (by specifying a length of 0) but can also be made a little thicker to improve grip, particularly on female threaded lock rings.
If designing either type of ring care should be taken to make sure that after inserting the ring there are enough free threads remaining so that the device can still be securely installed (check also this answer).
Most, but not all, types of lock rings or retaining rings can be designed online.
Female threaded lock rings are generally knurled while male retaining rings have spanner slots or holes to facilitate installation and removal.

Q. I just need a simple washer or spacer to adjust image train distance. Can you make this?

A. Washers can be created to fit most male threaded devices. First select the device or feature the washer must be installed over (this generally needs to be a male threaded device although washers for female features are possible in some special cases), then select Washer/Spacer on the other side (washer is listed under the "extensions and spacers" category). Lastly select the desired thickness for the washer. Please be careful not to make too thick a washer as the length of thread available on the device to be spaced-out must be taken into consideration. Most washers are made 1 to 2 mm thick (0.040 to 0.080 inch) at a maximum to leave enough free thread so the device can still be safely threaded with the washer installed. If you need a long spacer an extension tube will probably provide a better solution.
We can make washers as thin as 0.5 mm (0.020 inch).
If an error is displayed stating that a washer would not be useful for the selected feature, this generally means that the feature does not have the correct gender. The selected thread must be male to create a standard washer, but if the thread has a non-conventional reference point the female version needs to be selected instead. Check this answer for more information.
As a practical example selecting a generic T-thread device on the Telescope Side produces a washer with the appropriate inside diameter to slip over a standard male T-Thread.
Please note however that as a general rule we do not recommend adding washers in an image train as any additional interface can potentially compromise orthogonality, promote flexure, and decreases rigidity. It is normally desirable to install the minimum possible number of parts in an image train. Our Build-An-Adapter web app allows designing custom adapters at almost any length. This results in very accurate spacing while avoiding stacking extra components.

Q. Do you supply the screws with a bolted adapter order?

A. We supply appropriately sized stainless steel screws with bolted/flanged adapters.
Screw holes are countersunk or counter-bored to hide screw heads when the application requires a flat surface (noting that the countersunk/counter-bore is not displayed in graphics renderings).
We DO NOT supply screws for an adapter featuring a flange with tapped holes as we have no reliable way to determine the most appropriate screw type and length, and the needed screws are generally supplied with the device itself.
Noting that our graphical representation of tapped holes is a little simplified, displaying holes as untapped holes since rendering multiple threads in 3D could adversely affect older browsers performance.
All adapters featuring a dovetail pocket (aka dovetail receiver) come with three soft tip setscrews.
Eyepiece style adapters are supplied with either one or two thumbscrews, for 1.25 inch or 2 inch barrel size respectively, but also check this answer
For devices equipped with flanges featuring six equally spaced tapped holes we will generally make adapters with three bolt holes as this is necessary and sufficient to securely hold the device. The same is true for devices having 8 tapped holes, where the adapter is supplied with 4 holes and 4 screws. Adding more screws does not appreciably improve sturdiness and would make the part substantially costlier and assembly more cumbersome, noting that camera manufacturers usually provision six, or eight, tapped holes to allow more flexibilty in orienting the imaging system rather than to improve solidity.
Note: only the approximate locations of screws holes are shown on the 2D drawing. Please refer to the Virtual Reality 3-D Rendering for a more accurate rendering of bolt and screw holes.

Q. Can the adapter be knurled to facilitate installation and removal?

A. The outer diameter of a threaded adapter is knurled by default provided the edge is thick enough. A knurl can only be made on an edge that is at least 2 mm thick (or 0.1 inch or so). If the edge is too thin for a knurl we will add two spanner wrench holes or slots to assist in assembly or disassembly.
Bolted adapters or adapter without thread (for example with dovetail discs at both ends) are never knurled.

Q. Will the adapter have spanner holes or slots?

A. Adapters too small or too thin to be knurled will have appropriate spanner wrench holes, or, if there is insufficient room for holes, two spanner slots at 180 deg will be provided to assist in installing and removing the adapter.
Thin retaining rings have two spanner slots by default.
Spanner holes or slots are added automatically when needed and do not need to be requested separately.

Q. Is there a way to specify a rectangular piece in Build-An-Adapter?

A. Only cylindrical parts intended for inserting in an optical path can be designed with Build-An-Adapter.

Q. Can you provide an inner brass compression ring with a slip fit adapter?

A. A brass ring can be supplied for some slip-fit adapters. This feature is not normally included but can be added to the order for an additional charge. Expect about 20% extra over the cost of a simple adapter. Please add a note on the order page requesting the brass ring, or email us to that effect indicating the order number. The extra fee will be billed separately via PayPal.

Q. I need an adapter with anti-reflective surfaces.

A. Our adapters have finely ribbed internal surfaces and in addition receive a deep anti-reflective layer, while outside surfaces are anodized smooth black. These are standard features on all PreciseParts adapters.

Q. Can a male thread be made longer to provide additional room for inserting a lock ring?

A. We can extend a male thread in a custom adapter upon request:
First place an order for an adapter with the appropriate connections and an effective length THAT INCLUDES the amount of ADDITIONAL thread length the adapter should have, then add a note under "Note to Seller" on the PayPal payment page, indicating the ADDITIONAL thread length required. You can also email us the same information after placing the order, indicating the order number or the part reference.
For example if one needs a 20 mm effective length adapter with a male T-thread that is 5 mm LONGER then the adapter must be ordered with an effective length of 25 mm to account for the extended thread.
In most cases there is no extra charge for the extended thread, but if there is a charge it will be billed separately via PayPal after we receive your online order.
(Noting that a lock ring can be ordered online as well. Please check this answer for details).

Q. Can I change or alter features on a custom adapter?

A. Small alterations can be requested in a custom adapter as long as this does not substantially change the part dimensions or any of the connecting features or sizes. Typical changes include skipping black anodizing, making the part un-knurled, making a nosepiece without groove, or adding a provision for an internal filter. Noting that some change may have an extra charge, please consult us in case of doubt.
To request one of change described above you want to first place an order for the adapter with the required connections and length, then add a note in "Add instructions to seller" on the order page indicating the needed change, or email us the same information indicating the order reference number.

Q. Can adapters be anodized in color?

A. We can only anodize parts black, or clear by special request.

Q. The bolted adapter 3-D rendering only shows 3 holes when I was expecting 6 holes?

A. For devices equipped with flanges featuring six equally spaced tapped holes we will generally make adapters with three bolt holes as this is necessary and sufficient to securely hold the device. The same is true for devices having 8 tapped holes, where the adapter is supplied with 4 holes and 4 screws. Adding more screws does not appreciably improve sturdiness and would make the part substantially costlier and assembly more cumbersome, noting that camera manufacturers usually provision six, or eight, tapped holes to allow more flexibilty in orienting the imaging system rather than to improve solidity.

Q. I need an adapter to replicate a mounted filter thread.

A. Custom adapters for threaded filters can be easily created by selecting the appropriate filter thread size, on either the Telescope Side or the Camera Side according to the desired gender. A large selection of filter sizes are listed under "generic devices".
Noting that we do not recommend selecting a filter if the device to be connected is not actually a filter as this will almost certainly cause issue and the resulting adapter may not fit the device. This situation is not covered under our guaranteed fit policy.

Q. I need an adapter with the maximum possible inside diameter to prevent obstructing the light path.

A. Our automated design always strives to prioritize larger inside diameters, within the limitations imposed by the connecting features selected (such as threads or dovetails) while optimizing metal thickness to produce a solid and rigid connection.

Graphics and Drawings Questions

Q. No graphics rendering is shown on the page although I can see price and ordering information

A. If the graphics area on the left side of the build page is blank, your browser is probably outdated. You may want to check for a newer version, or alternatively use another browser.
If a message is displayed instead of the adapter drawing, your browser does not support HTML5. HTML5 is required to display the design drawing in our Build-An-Adapter web app.
We recommend using a current version of Firefox, Safari, Google Chrome, or Opera. The browsers available on most mobile devices, such as iPhone, Android, Blackberry or iPad, also work well. Internet Explorer supports HTML5 starting with version 10.
We strongly recommend against ordering a custom adapter without checking the drawing. The drawing provides a visual confirmation that the part will be made with connections compatible with your devices.

Q. Why are there no numeric dimensions on the drawings?

A. Dimensions are not explicitly displayed on the drawings since most dimensions are not in the public domain and some equipment manufacturers may consider this information proprietary, however the adapter 2D drawing does show how and where the effective length is measured from, and it is important to note that all other dimensions such as diameters and thicknesses are displayed in the drawings with correct proportions to help confirm that the adapter as designed will provide connections that are appropriate for the selected devices.
You may also want to check our warranty statement here.


Q. The part shown in the graphics seems to be slightly different from what I expected.

A. For best results we recommend our Virtual Reality 3-D view if your web browser supports WebGL. Virtual Reality 3-D renders the part to look almost exactly like the finished product but note that some specific features are currently partially rendered:
  • A DSLR lens adapter cannot currently be rendered in 3-D at all. Please refer to the 2D view for this type of adapter.
  • Bolts and screws holes are only shown in Virtual Reality 3-D view, while the 2D drawing just shows their approximate locations.
  • Tapped or countersunk holes are displayed the same as smooth holes; this is done to avoid slowing down rendering in older web browsers.
  • In rare cases where a custom adapter needs TWO SETS of radial holes only ONE SET is shown in the 3-D rendering but rest assured that the final part will have both sets of holes. The 2-D drawing shows both sets.
  • Certain features such as some special centering tapers are now shown in either 2-D or 3-D.
  • We may remove some extra metal during manufacturing to lighten parts, particularly in bulky adapters where very thick walls are not generally necessary.
  • A few devices require a flange with slots but the 3-D rendering might show simple holes instead of slots. Examples are prime focus adapters for the Celestron RASA family of instruments. We do have the exact specifications from the manufacturer on file and we will machine these features accordingly.


Q. I see a male thread on the drawing where I am expecting a female (and conversely).

A. When selecting a generic feature, please be sure you select the gender of the device to be connected rather than the gender you want on the adapter.
If a particular device is selected and the thread does not seem right, please first confirm you have selected the device on the correct side, as selecting a device on the wrong side is the most common cause of inverted gender, but if you have confirmed the side and the gender still does not seem right please let us know and include the reference number obtained online; we will then gladly review our device specifications.

Q. My mobile device does not show the 3-D rendering very well.

A. Most mobile devices are slower than desktop or laptop computers and some have difficulties displaying the 3-D model interactively.
On a small screen device such as a smart phone it helps orienting the device in portrait mode before starting the 3-D view as this prevents cutting off part of the 3-D graphics. The Virtual Reality 3-D does work better than our regular 3-D on an iPhone but iOS version 8.1 or later is required as earlier versions do not support WebGL.
If only a blank window appears when selecting the Virtual Reality 3-D model on an iPhone or iPad with iOS 8 or newer, try flipping your screen back and forth (from portrait to landscape, or vice-versa) but first you want to make sure the current orientation is not locked. The 3-D rendering should then show properly.

Q. When I try the Virtual Reality 3-D my web browser shows a blank window, or says WebGL is not supported.

A. The Virtual Reality 3-D view requires a recent browser with support for WebGL (see this answer for more information about WebGL). Nowadays practically all newer browsers and mobile devices support WebGL, but very old browsers generally do not, and new browsers on older computers will almost certainly fail. Some browser, such as Apple Safari on macOS requires WebGL to be explicitly enabled, thus we recommend using either Firefox or Google Chrome since there is no need to explicitely enable WebGL in these browsers, but if Safari is your only available browser you might want to try the following to enable WebGL:
In macOS 10.8 and earlier, check the Developer menu button in Preferences->Advanced, then click the "WebGL" choice in the Developer menu at the top of the screen. In Safari on macOS 10.9 or later, the WebGL button is in Preferences under the Security Menu.
If the Virtual Reality 3-D function continues to show a blank window after enabling WebGL in Safari, try resizing the browser window just a little to refresh the graphics window and make the 3-D rendering appear.
Mobile Safari on iPhones and iPads in principle supports WebGL by default but if clicking the Virtual Reality 3-D icon shows a blank white window try rotating your device to flip the screen orientation back and forth. This simple action usually suffices to display the 3-D rendering.

Q. What is WebGL?

A. WebGL is an open source, cross-browser 3-D graphics platform for HTML. It uses the OpenGL shading language and can be cleanly combined with other web content that is layered on top or underneath the 3-D content. It is ideally suited for dynamic 3-D web applications in the JavaScript programming language, and all leading web browsers are committed to fully support WebGL. WebGL is fully integrated into the browser and is NOT a plug-in.
As an API for the World Wide Web, WebGL necessarily conforms to the security principles of the web platform, and was designed with security in mind from day one.
Confirm whether your browser supports WebGL.
Also check the Khronos site for detailed information about WebGL.

Q. The adapter shown in the graphics seems to have an extra shoulder or step?

A. The device to be connected probably requires some kind of clearance, which may translate to a step or shoulder machined at the maximum diameter which still clears the device.
If the device is on hand you want to check for any protrusion or obstruction which would limit the connection diameter. This type of obstruction is frequently found on filter wheels and OAGs where the electric motor or guide port gets in the way for larger diameter connections.
Build-An-Adapter takes care of this clearance automatically, so you don't have to...

Q. The red reference lines where the effective length is measured seem to be incorrectly placed on the drawing?

A. The vertical lines indicating the adapter effective length may appear shifted left or right under rare circumstances, however rest assured that the effective length value displayed is correct and its accuracy is not affected.
The issue is caused by a graphics artifact that might show up when the effective length is measured from a non-standard reference point.

Price questions

Q. Why is the cost higher than the price of a similar commercial part?

A. The cost of a one-of-a-kind, custom made part will always be considerably higher than an off-the-shelf part manufactured in volume since the latter is produced through a less labor-intensive process.
PreciseParts excels in machining precision components that are either too specialized to be economically mass-manufactured or that are no longer available from their original suppliers.

Q. The custom adapter costs more than I expected.

A. Some features can increase the cost of an adapter dramatically. For example a long adapter with a large difference in internal diameters at each end will most likely require machining the part from solid aluminum stock, making the price considerably higher than machining a short part from tube stock.
Consider that the price of a machined part is closely related to the amount of metal that needs to be removed thus if an adapter can be made from a thin tube stock the cost will be subtsantially lower, but clearly this is not always physically possible.
The vast majority of custom adapters we make in larger diameters (eg. 4 inch/100 mm or more) are one inch (25 mm) or less in length and if your particular adapter requires a longer length you want to first check if some standard off-the-shelf components, such as extension tubes, thread reducers, or step-down rings, can be inserted in the image train to help reduce the custom adapter length or its diameter, or both. Another strategy that is sometimes effective is altering the sequence of existing components in the image train to minimize both the length and diameter difference of a custom adapter.
These simple steps are likely to help drop the cost of the custom adapter substantially.

Ordering and Payments

Q. What are the payment options?

A. The easiest way to order and pay for a custom adapter is to click the Add to Cart button at the bottom of the price page. A secure PayPal page will be displayed with a description of the item(s) ordered. Payment can be completed with either a credit card or through a PayPal account. Please be sure you include an accurate email address if paying with a credit card. We will email an order acknowledgment within minutes of receiving your order and provide a confirmed shipment date.


Q. Do you accept credit card payments?

A. We accept credit card payments through PayPal. Just select "Pay with Debit or Credit Card" on the PayPal payment page.
Regrettably we cannot accept credit cards through other methods, such as over the phone or via email.

Q. Can I order two or more adapters in a single order?

A. Certainly, Build-An-Adapter uses the Shopping Cart functionality and 'cookies' so any number of items can be ordered in a single order. Your browser should be configured to accept "cookies" (most browsers accept cookies by default). Just add your first item to the shopping cart and after the cart content is displayed click the "Continue Shopping" link to return to Build-An-Adapter to design additional parts. You can also open separate browser windows to create more parts. The shopping cart will be keep track of all the adapters saved.
The items you put in your cart are saved until the order is placed. Items can be kept for several days or until cookies are cleared from your browser cache.

Q. My organization is not able to order online. Do you accept a Purchase Order?

A. Certainly, we do accept Purchase Orders in US$ from corporations, for shipping within the USA. Just let your purchasing agent know the reference number(s) you wish to order, together with the price(s) displayed online on the Build page. This is the only information we need on the Purchase Order. We do not charge sales tax. Payment with a mailed paper check is acceptable. Domestic shipping is free.
We recommend emailing the PO to us at address payment@preciseparts.com. We will then immediately email a formal invoice in PDF format and provide a confirmed ship date.
Please note that if your organization is able to pay by credit card we suggest placing the order online as this is easier and faster than emailing us a purchase order. Please ask your purchasing agent to access Build-An-Adapter and select the Telescope Side and Camera Side connections and the desired length for the adapter you need. We will gladly assist your agent over the phone if he or she supplies a Build-An-Adapter reference number. But please note that all our reference numbers are dynamically generated and therefore unique and we are not able to process an order offline, ie. over the phone, based solely on a reference number unless the number is specified as an item in a Purchase Order.

Q. How do you confirm you received my order?

A. We automatically email an order acknowledgment, and provide a firm ship date, soon after receiving your order. Online orders are generally confirmed within minutes, 7 days a week, 24 hours a day. Our confirmation email is sent from email address payment@preciseparts.com to the address supplied in the [PayPal] payment record.
If you cannot locate the confirmation email please first check your junk or spam folders for lost messages.
You may also want to verify your email client and email server filter settings as so-called "spam filters" are by far the most common cause of undelivered emails. Incidentally, certain email services are notorious for preventing legitimate emails from being delivered based on criteria only known to these services.
We also provide online order status on our web site. The whereabout of your order can be checked at any time here.

Q. Do you take orders over the phone, or via email?

A. No. Since all our products must be designed online to fit specific applications we are not able to take orders over the phone or by email.
However we can certainly help you place an order online but first please be sure to have all needed information and requirements at the ready as regrettably we are not able to assist with equipment and devices questions.

Q. When trying to pay for my order I get a message from PayPal stating "this invoice has already been paid".

A. This issue is almost certainly caused by old PayPal cookies left over in the browser. We suggest trying to clear all cookies labeled paypal.com in your browser. The procedure to clear cookies is slightly different and depends on the specific browser and version, but generally cookies can be accessed from the browser Preferences menu under Privacy. If clearing cookies ends up impractical we recommend trying another browser or switching from a mobile to a desktop browser, or vice-versa.

Q. Is it possible to cancel an order?

A. An order can be cancelled if we have not yet started fabrication. When we start fabricating a part depends essentially on our backlog. If an order needs to be cancelled we recommend contacting us as soon as possible, preferably by REPLYING DIRECTLY to our order confirmation email message.
If cancellation is possible we will promptly refund the payment minus any fee PayPal might charge us for processing the payment.
Please be aware that if an order includes more than one part we will need to cancel the whole order as it is not possible to cancel just one item in a multi-parts order.
Regrettably we are not able to refund an order once we have started fabricating a part.

Q. I placed an order but did not get an email confirmation?

A. We email an order confirmation as soon as an order is received. Our confirmation is sent from email address payment@preciseparts.com to the email address supplied in the [PayPal] payment record.
If you cannot locate the confirmation email please first check your junk or spam folders for lost messages.
You may also want to verify your email client and email server filter settings as so-called "spam filters" are by far the most common cause of undelivered emails.
Please note that we also provide online order status directly on our web site. The whereabout of an order can be checked at any time on our Order Status Page.

Q. I placed an order with the wrong length. Can you correct it?

A. An order placed for an adapter at the wrong length, or with the wrong features, will need to cancelled and the part re-ordered. We are not able to change any dimension in a part sent to our production as our machining environment is completely automated.
The easiest and quickest way to request a cancellation is to reply to our Order Confirmation email, but you may also want to check this answer to confirm whether a cancellation is still possible.

Q. Do you offer a discount for quantity orders?

A. As we essentially make parts one at a time using automated machining, we are regrettably unable to offer a volume discount no matter the quantity ordered, although if all the parts ordered are shipped together shipping costs will generally be lower on a per unit basis.
Please also check this answer.

Shipping and Delivery

Q. How will you ship my order?

A. United States Postal Service Priority Mail is the Standard Domestic shipping method and delivers in 2-3 days. Alternatively, USPS Express Domestic can be selected at checkout. Express Mail delivers overnight to most U.S. destinations.
Both domestic methods include a tracking number which will be emailed to you the moment the package leaves our door.
When selecting a shipping method please first take into consideration that it may take up to 6 business days to fabricate the part, or parts, ordered.
We ship all packages from the Miami, Florida USA area. Standard domestic Priority Mail delivers overnight within Florida, as well as within most bordering states, thus there is no need to select a faster ship method for destinations within these areas.
For non-US destinations we ship either Priority Mail International (1-2 weeks in transit) or Express Mail International (usually 5-7 days). Shipping cost for the destination country is calculated on the checkout page.
Express Mail International offers full Internet track and trace updated several times a day for most destination countries. Packages shipped Priority Mail International can also be tracked although the package progress is updated somewhat less frequently.
It is also generally possible to track our package on the destination country domestic postal service; the same tracking number supplied by the US Postal Service can be used with the local postal service. Please check your country's postal service web site for a tracking page.

Q. When do I get my custom adapter if I order it today?

A. Turn-around at any given time is based on our current backlog and we always strive to provide a reasonable delivery time. We currently can have parts shipped within 6 business days from the order date.
We email an order confirmation and a guaranteed ship date within minutes of receiving an order.
Please contact us for special requirements indicating your order number.

Q. Do you have an extra charge for quick delivery?

A. No, but if you have an emergency we will do our best to prioritize your part. In such circumstances we recommend ordering the part as early as possible, selecting the fastest shipping option available on the payment page, AND, very importantly, letting us know WHEN you need the part. We will then do our best to take your requirements into account when we schedule the order for production, but please be aware that this is subject to our current work load. Please contact us with your requirements via email, indicating your order number, or simply by replying to our Order Confirmation email.

Q. How can I select a shipping method?

A. Either Standard Priority Mail or Express Mail can be selected at checkout on the payment page after choosing the method of payment. Please do not use the "Estimate Shipping" button sometimes offered by PayPal on the initial "Shopping Cart" page as the amount shown might not be accurate.


Q. I am located outside the USA. How do you ship internationally?

A. We ship worldwide with either United States Priority Mail International or Express Mail International (see also this answer). Please note that our prices do not include any Value Added Tax or duty thus be aware that depending on the destination country such charges may be due before the package can be delivered. Although we have no control over the import regulations specific to each country, we do try to minimize destination charges by clearly describing the content and values on the outside of the package and we also add an appropriate customs classification code for astronomical telescope accessories as these products may benefit from favorable tax/tariff treatment.
We will email an online tracking link as soon as the shipment has been processed in our facilities.
It is generally possible to also track our package on the destination country postal service web site, The original tracking number supplied by the US Postal Service can also be used with the local postal service. Please check your country's postal service web site for a tracking page.
In any case, we recommend always checking available tracking sites to ensure the package is being routed properly at destination and contact the local postal service in case of issue.
Special note for United Kingdom destinations: we recommend closely following the progress of the shipment after it arrives in the UK as a number of our packages have been held in customs awaiting payment of charges without the recipient being notified.

Q. I did not get a shipping notice.

A. We automatically email a ship notification and tracking number as soon as the order is packed and leaves our facilities.
The shipment notice email is sent to the address supplied in the [PayPal] payment record, and is sent from email address shipment@preciseparts.com.
If the email message is missing please first check your junk or spam folders for lost messages.
You may also want to verify your email client and email server filter settings as so-called "spam filters" are by far the most common cause of undelivered emails. Incidentally, certain email programs are notorious for preventing legitimate emails from being delivered based on criteria only known to them.
We also provide online order status on our web site. The whereabout of your order can be checked at any time here.

Q. What is the cost to ship internationally?

A. The shipping costs depend on the destination and are shown on the order page. The desired ship method can then be selected before finalizing the order.

Q. My international order seems to be stuck in customs. Can you help?

A. Unfortunately there is nothing we can do from here as we are not able to contact customs organizations or postal services in foreign countries, noting however that a package is generally held in customs awaiting payment of duties and/or VAT and we recommend contacting the local postal service for further information.

Fabrication

Q. What material are the parts made from?

A. All adapters are made from high strength 6061 aluminum and anodized smooth black. Internal surfaces are finely ribbed and treated with an anti reflective layer.
Dust caps are made of black Acetal, a tough engineering plastic. The edge of the cap is knurled if room allows.

Q. Can you make parts in volume?

A. PreciseParts specializes in making one-of-a-kind components essentially one at a time. This is where we believe we can best serve the astronomy community. Although we can generally make two or three units for a reasonable price, we would suggest contracting with a production machine shop to make parts in higher volume at an optimum cost.
We can also prototype a part, for example to test design iterations. The availability of a prototype can then substantially facilitate dealing with a production shop at a later time.

Q. At what level of precision do you machine parts?

A. Our machining tolerances depend on the particular feature. For example some threads require a larger allowance than others to ensure our adapters will fit in all circumstances.
We generally machine adapters to a maximum of +-0.001 inch (+-0.02 mm) differential thickness (aka "wedge" error), and better than plus and minus 0.005 inch (plus and minus 0.1 mm) for effective length.

Q. How are thread lengths determined when machining parts?

A. We machine a thread at the exact length, or depth, specified by the device manufacturer. This rule also applies to other proprietary device features such as dovetail discs and bolted flanges thicknesses. For generic threads, the length or depth we use is the average value generally found in common non-brand name astronomy connectors.

Q. How does PreciseParts machine adapters?

A. Please check this short video showing a typical part being machined on the CNC.

Warranty

Q. Can I return the part if it doesn't fit?

A. We stand behind our design and will promptly replace or rework a custom adapter if it does not fit either or both devices the part was ordered for, or if the part length does not match the effective length ordered. Please see also our warranty statement here.

Q. What kind of warranty do you offer?

A. We will replace or rework a custom adapter if it does not fit either of the devices the adapter was ordered for, or if the part length does not match the effective length ordered, within a reasonable tolerance commensurate with the application.
Any claim for replacement or repair must be made within 60 days of delivery date.
All the parts we make are unique and machined exactly according to the customer-created design, and this regrettably precludes any return. All sales are therefore final unless the part is defective as defined above.
Please note that we cannot warrant that the part will fit a particular purpose or a specific instrument setup, and we expect our customers to assume full responsibility that the adapter morphology and length as ordered are appropriate for the application.
We also cannot anticipate all possible interferences between two devices interconnected by our adapters, therefore it is the customer responsibility to verify before ordering that equipments installed in close proximity will not interfere with each other. The part's 2D drawing and the 3-D virtual reality rendering offered on our site are useful to verify possible interferences.
Disclaimer: Many devices share similar designations but have different specifications, and to ensure you are selecting the correct devices please always verify the adapter scale drawing displayed on the left side of the price page to ensure the general features match the equipments the adapter is intended for. If an order is placed using a browser that cannot display the drawing we will not warrant the design therefore the provisions outlined in this paragraph become null and void.
If your browser cannot display the drawing, please check this answer.

Security and Privacy

Q. What is your privacy policy?

A. When you visit or view PreciseParts.com, our server automatically collects some information about you such as your IP address and browser type, however this information is used ONLY for our own internal statistics and will NOT BE SHARED with third parties.
Our web pages are completely free of advertising and we will never try to sell you anything other than the products we directly make.
If you place an order with us, we WILL NOT share ANY of your personal information, such as email address, shipping address, phone numbers, browsing history, or order record with any other party unless you explicitly authorize us to do so.
If you use a credit card to pay for an order, the credit card number and associated information is only available to our payment processor (PayPal) and is not communicated to us. We will never ask for your credit card information over the phone or via email.
We do not require users to open an account or register in any way to use our service. Our web site does not use cookies, but if you place items in your shopping cart our payment processor (generally PayPal) will store cookies in your browser with the only purpose of keeping track of items in your shopping cart. We believe this is a legitimate use of cookies as these cookies will not be used to track your purchasing habits or create targetted advertising.
Our web pages do not include any social networks links or buttons, such as Facebook "Like", or Tweet/X, to prevent tracking of your browsing information by unrelated parties.
If you wish to contact us, you can find our contact information here. Comments or feedback can also be left on that page, even anonymously, but if you wish to include your email address we will be glad to reach back.


Q. Is it safe to order online?

A. Our orders and payments are processed directly by PayPal. PayPal is one of the safest and most trusted payment system worldwide. Your personal information (including credit card data if paying with a credit card) is only known to PayPal. PayPal only shares with us the personal information we need to fufill your order, essentially your name, shipping address and email.

Q. Does your web site store cookies in my computer?

A. While our web site by itself does not use cookies, placing an item in your shopping cart causes PayPal, our payment processor, to create a cookie to keep track of the items saved in your cart. If you elect not to place an order immediately your cart content can be retrieved later without the need to re-create the parts.
The items in your shopping cart are saved for several days, until you actually place the order, or until the cookies in your browser are cleared. You can of course also remove items manually from your shopping cart at any time.