Photo thread library for Autodesk Fusion

Update, 2024-8-22: Here comes a big one… would call this a major update:
1) Added Newport/Thorlabs SM05, SM1, and SM2 threads (with friendly support by user @FWest_1838166).
2) Added 0.75 mm pitch filter threads ø 35 mm, 46 mm, and 82 mm, so now the 0.75 filter thread range is complete (at least as long as chinese engineers keep to what makes sense).
3) Added 1.0 mm pitch filter threads ø 86 mm, 95 mm, and 105 mm.

Update, 2024-2-08: Added 37 mm filter threads by request.

Update, 2024-1-20: Added two (coarse) tube connector threads and quite a bunch of filter threads.

Update, 2022-08-14: Added 52mm threads (x0.75 and x1.0)..
 

What is this?

Some threads that are quite common with optical equipment are too “exotic” to show up in Fusion360's regular thread menu, making it hard to design an otherwise simple lens adapter or extension tube. So I made an XML library that contains the most important thread definitions used with photo gear, including:

• SM05 (0.535"x1/40"): This is a very fine thread used for connections of optical tubes at a diameter of half an inch.
  Since a Fusion360 thread library can only contain either imperial or metric information, I converted the original inch values to mm. Thus, the thread diameter shows up as 13.5 mm instead of 0.535".
• RMS (0.8"x1/36"): This was the standard thread for finite microscope objectives for decades. With the introduction of infinite objectives most brands switched to proprietary threads, but at least for finite objectives the RMS thread is still the #1 standard. More important for photographic purposes, it is also used for bellows lenses like the famous Zeiss Luminar series, the Zuiko Macro series from Olympus, or the Macrophoto lenses from Canon.
  Since a Fusion360 thread library can only contain either imperial or metric information, I converted the original inch values to mm. Thus, the thread diameter shows up as 20.32 mm instead of 0.8".
• Nikon Micro (M25x0.75mm): This is the thread used for newer (infinite) Nikon microscope objectives (and imitations of those). 
  The M25x0.75mm thread is also the standard filter thread for lenses with a front diameter of 25 mm.
• SM1 (1.035"x1/40"): This is a very fine thread used for connections of optical tubes at a diameter of one inch.
• Mitutoyo Micro (M26x0.7mm): This is the thread used for Mitutoyo microscope objectives (and imitations of those).
• 28mm Filter thread (M28x0.75mm): This is a regular lens filter thread for lenses with a front diameter of 28 mm. This was the case with the early Nikon Coolpix 9xx (and subsequent) cameras which (then) were the perfect choice to adapt macro/micro equipment, so you still sometimes find high quality micro tubes and adapters with a 28 mm thread on the used market. 
• 30mm Filter thread (M30x0.75mm): This is a regular lens filter thread that can be used as an intermediate connection for a (metal) step-down filter adapter to achieve a more robust end connection.
• 30mm Tube connector thread (30x2.40mm): This is a nonstandard thread I designed especially as a robust and easily printable connection for tubes and lens plates or tubes of different diameters. For an application example have a look at the manual section below.
• 35mm Filter thread (M35x0.75mm): This is a regular lens filter thread for lenses with a front diameter of 35 mm.
• 37mm Filter thread (M37x0.75mm): This is a regular lens filter thread for lenses with a front diameter of 37 mm.
• Leica (39x0.977mm): The camera/lens connection thread of the early Leica rangefinder cameras. Though quite irrelevant as such nowadays, the thread has gained additional relevance as a de-facto standard for enlarger lenses.
• M42 (M42x1.0mm): A thread that was used for camera/lens connections by different camera brands (including Pentax and Practica) in the past. Today it is used widely for intermediate lens tube connections in macro/microphotography.
• T2 (M42x0.75mm): This similar thread was introduced 1957 by Tamron as a (lens-side) basic thread to be used with various bayonet/thread adapters to fit cameras of different  systems. Today it is very common especially with telescope equipment. 
  The M42x0.75mm thread is also the standard filter thread for lenses with a front diameter of 42 mm.
• 46mm Filter thread (M46x0.75mm): This is a regular lens filter thread for lenses with a front diameter of 46 mm.
• M48x0.75mm: Another thread typical for telescope equipment, (obviously) needed for bigger tube diameters.
  The M48x0.75mm thread is also the standard filter thread for lenses with a front diameter of 48 mm.
• Raynox Back (M43x0.75mm): The Raynox DCR150 and DCR250 are popular close-up converters, offering very high image quality at a reasonable price. They can also be used as high-quality tube lenses for microphotography. This is the thread to connect one of these converters to a lens or lens tube.
  The M43x0.75mm thread is also the standard filter thread for lenses with a front diameter of 43 mm (which is just natural since the DCR converters usually are mounted in front of lenses).
• Raynox Front (M49x0,75mm): This is the front thread/filter thread of the above Raynox converters, needed to attach filters, tubes, or additional lenses.
  The M49x0.75mm thread is also the standard filter thread for lenses with a front diameter of 49 mm (which is its original purpose as well with the raynox converters when used in front of a lens). This, like the 52mm filter thread, is a very common diameter, so you will typically find more step-up/down adapters for 49 or 52 mm than for most other sizes.
• SM2 (2.035"x1/40"): This is a very fine thread used for connections of optical tubes at a diameter of two inches.
• 52mm Filter thread (M52x0.75mm): Added this because it is one of the most common threads for reverse lens adapters as well as a good inner tube diameter (as smaller diameters may cause vignetting with full frame sensors). Use it to add a bayonet connector to a tube by simply screwing on a reverse lens adapter.
• M52x1mm: Bigger pendant to M42x1mm. The wider diameter prevents vignetting when used with full-frame FX sensors. 
• 52mm Tube connector thread (52x2.40mm): This is a nonstandard thread I designed especially as a robust and easily printable connection for tube segments. For an application example have a look at the manual section below.
• 55mm Filter thread (M55x0.75mm): This is a regular lens filter thread for lenses with a front diameter of 55 mm.
• 58mm Filter thread (M58x0.75mm): This is a regular lens filter thread for lenses with a front diameter of 58 mm.
• 60mm Filter thread (M60x0.75mm): This is a regular lens filter thread for lenses with a front diameter of 60 mm.
• 62mm Filter thread (M62x0.75mm): This is a regular lens filter thread for lenses with a front diameter of 62 mm.
• 67mm Filter thread (M67x0.75mm): This is a regular lens filter thread for lenses with a front diameter of 67 mm.
• 70mm Filter thread (M70x0.75mm): This is a regular lens filter thread for lenses with a front diameter of 70 mm.
• 72mm Filter thread (M72x0.75mm): This is a regular lens filter thread for lenses with a front diameter of 72 mm.
• 77mm Filter thread (M77x0.75mm): This is a regular lens filter thread for lenses with a front diameter of 77 mm. This filter thread size is especially popular with medium format camera lenses.
• 82mm Filter thread (M82x0.75mm): This is a regular lens filter thread for lenses with a front diameter of 82 mm.
• 86mm Filter thread (M86x1mm): This is a regular lens filter thread for lenses with a front diameter of 86 mm. Note that from this size upward the regular filter thread pitch is 1 mm instead of 0.75 mm.
• 95mm Filter thread (M95x1mm): This is a regular lens filter thread for lenses with a front diameter of 95 mm. 
• 105mm Filter thread (M105x1mm): This is a regular lens filter thread for lenses with a front diameter of 105 mm. 
   

Something missing?

Well, I have excluded the regular tripod threads for the simple reason that you can't put metric and imperial threads into the same library in Fusion360. Yet these are not exotic threads anyway; you can find them in Fusion's standard thread libraries under 
ANSI Unified Screw Threads → 0.25 in → ¼-20 UNC and
ANSI Unified Screw Threads → 0.375 in → 3/8-16 UNC
Same applies to the C-Mount and CS-Mount threads (popular in videography); these are found as well in Fusion's standard thread libraries under
ANSI Unified Screw Threads → 1.0 in → 1-32 UN
(Note that it's just this one thread to be used for C-Mount and CS-Mount as well since they only differ in flange focal distance)

If there's anything else you would like to see in the library, just drop me a line in the comments - but keep in mind that I can't define a thread I don't know the specifications of. In clear words, if you can't supply complete specifications, at least you will have to do the beta tester job for a thread that I add for your sake.
 

Instructions

One hint ahead: If you download via the “All (xxx) files” buttons, you get a PDF version of this page along with the files. Thus you always have an instruction manual that's the same version as the corresponding files.
 

Installation (manually - not recommended anymore):

1. Download the attached file named “StephansTubusgewinde.txt”.
2. Change the suffix from “.txt” to “.xml” (printables.com does not allow the upload of .xml files, so I had to rename it).
3. Go to this page and follow the instructions to find the thread library folder of your Fusion360 installation. Note that you don't need to follow any instructions on the page - all you need is to find the “ThreadData” directory as described under “2. Browse to the following directory:”.
4. Put a copy of the file now called “StephansTubusgewinde.xml” into “ThreadData”.
5. Start (or restart) Fusion360. From now, whenever you open one of the thread dialogs, a new thread type will show up in the thread types menu, called “Stephans Tubusgewinde”.
   
   
   
   Please note that the thread definitions are intended to be used for 3D printing only - if you try to use them for CNC milling, your CAM may find my tool designations a little funny. 
   Reason why I don't recommend this installation method anymore is that after a Fusion360 update you will have to do the installation anew. To avoid this, use the ThreadKeeper plugin instead:

Alternatively: ThreadKeeper installation (recommended)

1. Download the attached file named “StephansTubusgewinde.txt” as well as the (free) ThreadKeeper plugin from the Autodesk app store.
2. Install the ThreadKeeper plugin while Fusion360 is not running. Then start Fusion360 and go to the “Utilities” tab.
3. In the new “ThreadKeeper” menu, choose “Open ThreadKeeper directory”.
4. Drag “StephansTubusgewinde.txt” into the TheadKeeper window that you opened in the previous step, then change its suffix from “.txt” to “.xml” (printables.com does not allow the upload of .xml files, so I had to rename it).
5. In the “ThreadKeeper” menu in Fusion360, choose “Force sync”.
6. From now, whenever you open one of the thread dialogs, a new thread type will show up in the thread types menu, called “Stephans Tubusgewinde”. Unlike with the manual installation described above, it will persist even after a Fusion360 update.

Using the threads: (1) in Fusion360

Open a thread dialog in Fusion360 and choose the thread type “Stephans Tubusgewinde”. Now you can choose one of the thread definitions above by diameter and name.
To keep things from getting too comfortable, there is a limitation in Fusion360's XML syntax which is a little unflexible: You have to select the threads by diameter instead of name. Verbose names can only be listed as a diameter's subgroup, so you will find the thread names only after selecting the diameter first:

Choose “13.5 mm” to select SM05.
Choose “20.32 mm” to select RMS.
Choose “25 mm” to select Nikon Micro.
Choose “26 mm” to select Mitutoyo Micro or SM1.
Choose “28 mm” to select 28mm Filter thread.
Choose “30 mm” to select 30mm Filter thread or 30mm Tube connector thread.
Choose “35 mm” to select 35mm Filter thread.
Choose “37 mm” to select 37mm Filter thread.
Choose “39 mm” to select Leica.
Choose “42 mm” to select M42 or T2 (the latter being the 42 mm Filter thread as well).
Choose “43 mm” to select Raynox Back (which is also the 43 mm Filter thread).
Choose “48 mm” to select M48x0.75 (which is also the 48 mm Filter thread).
Choose “49 mm” to select Raynox Front  (which is also the 49 mm Filter thread).
Choose “52 mm” to select 52mm Filter thread or M52x1mm or 52mm Tube connector thread or SM2.
Choose “55 mm” to select 55mm Filter thread.
Choose “58 mm” to select 58mm Filter thread.
Choose “60 mm” to select 60mm Filter thread.
Choose “62 mm” to select 62mm Filter thread.
Choose “67 mm” to select 67mm Filter thread.
Choose “70 mm” to select 70mm Filter thread.
Choose “72 mm” to select 72mm Filter thread.
Choose “77 mm” to select 77mm Filter thread.
Choose “82 mm” to select 82mm Filter thread.
Choose “86 mm” to select 86mm Filter thread.
Choose “95 mm” to select 95mm Filter thread.
Choose “105 mm” to select 105mm Filter thread.

The thread definitions do not contain any compensation for “growth effects” caused by overextrusion in 3D printing. In most cases you won't need any compensation anyway, but if your printed threads are too tight to fit (which may be the case for plastic/plastic screw connections), you may want to modify them individually (assumed you don't need to revise your extruder/filament calibration). In case you don't know how to do this, have a look at the .f3d file I attached as a demo for widening/narrowing threads. Just follow the steps in the file's timeline and watch the object change. This works for male threads as well as for female ones.

If you are designing a long tube ("long" in that respect means bigger in length than in diameter) like the one in this screenshot…



…and want to produce it using an FDM printer, I recommend to not design it as a single part with threads on both ends, but split into multiple (i.e. at least two) parts (which, of course, have to be glued (or screwed using a coarse thread) after printing) as visible in this section view of the same object:



Reason is that, as detailed below, the threads should always be printed in a very high resolution (low layer height) while for the tube body a coarse resolution is sufficient. But it's not a good idea to switch from 0.2 mm layer height to 0.05 mm at 100 mm total print height - quite likely the print's surface will be too erratic to keep the nozzle from scratching the surface and kick your object off the buildplate. So, it is safer to separate the model into two parts, thus allowing for first printing the thread at a fine layer height and then printing the rest of the part in a coarse layer height (also see slicer screenshot below).

There are two threads in the collection that visibly differ from all the others: The 30mm and 52mm Tube connector threads. These are proprietary coarse threads I designed especially for connecting 3D printed parts to other 3D printed parts. They are solid enough to be used many times, so they are well suitable for applications in which exchangeable parts or different part combinations are used.
The 30mm Tube connector thread is primarily there to be used as an intermediate size adapter connection like this:

In contrast to this, the 52mm Tube connector thread is designed especially to connect multiple tube segments of the same diameter:

The 52mm thread width allows for an inner tube width of up to 47mm which is sufficient to avoid vignetting when used with full frame FX sensors. 
Both of the Tube connector threads can be printed with a layer height of 0.2 mm (in contrast to the finer optical threads that need an as-fine-as-possible layer height).

Using the threads: (2) in your slicer application

All of these threads (except for the tube connector threads, of course) are quite delicate, so I recommend to use a layer height of 0.05 - 0.07 mm to print the threads (if using an FDM printer - if you should have an SLA printer (which I think is the better choice but have no experience with), use 0.025 or even less instead). However, for the non-threaded parts of your models there is no need to waste time and energy printing that fine (and slow). In the example below the use of variable layer height saves about 9 hours of printing time (which equals about 1.4 kWh of energy).
In PrusaSlicer, as well as in its derivates BambuStudio and OrcaSlicer (most likely SuperSlicer as well), it is not possible to change layer height by means of modifiers, so in these slicers, unless you (further) cut your model into multiple parts, you have to use the (laborious) variable layer height option. In case that you have never used this option before, have a look at the two example .3mf files I attached. One is the very same object as in the Fusion360 screenshots above, two parts positioned for sequential printing featuring layer sizes between 0.05 mm and 0.2 mm. The other one is a short tube, printed as one part with threads on both ends. To see the effects of variable layer height settings, open the files in PrusaSlicer, click the variable layer height button in the horizontal toolbox at the top of the screen, and then select one of the objects on the buildplate. The rest should be self-explanatory.
A tip: Before you set layer heights, set the maximum layer height limit in the printer settings/extruder settings to the value you want to use for the thicker layers (0.2 mm in the example file). 




In Simplify3D it's easy to use multiple layer heights in one print, so if you still have this stone age application, this is one of the rare cases in which it is useful.
Last but not least, if you use Cura, there is (as far as I know) no way of manually changing the layer height within one print object. Instead, you have to use the automatic feature called “Adaptive layer height” that is configured by entering some standard and threshold values. I myself have no idea of how good this works.
Oh, and please do not print these example files - they are good for nothing but demonstration purposes. If you want to show me some “makes”, I'd be happy to see screenshots of your Fusion360 designs using the thread library.
 

Material choice (FDM printers)

First of all: Use a filament that is as black and as dull as possible. Interfering light reflections caused by a glossy material are a real photo quality killer. Alternatively you can apply some dull black varnish to the inside of your models, but I think that you should take care not to varnish the threads.
Second, especially for the finer threads with less than 1 mm pitch, your filament should handle overhangs very well, so PETG is not a good choice. PLA does a better job. My favourite for this purpose is Extrudr Greentech Pro which also features a matt surface. 
 

A few words about rigidity

Normally lens tubes, adapters, and the like are made of metal. For a reason - plastic threads wear out easily. If you screw and unscrew your printed threads regularly, they will pretty soon be beat-up. But if you use a setup in which you have to screw on gear just once (and for all) and never have to take it off again, even plastic parts are rigid enough to be used for many years. Here's my strategy to accomplish this - cheap but uncompromising:

• First of all, I consider if I need to regularly change connected devices on both ends of the adapter/lens tube I plan to make. While this is needed in most cases on the camera side, there are many cases in which the lens or objective may stay “forever” connected to the adapter/tube.A good example are finite microscope objectives or reversed enlarger lenses - you will never use them without an extension tube, and you need an individual tube length for each of them anyway.
• So, if I want to connect a lens that may remain mounted to the printed part (and that is light enough to be carried by the plastic thread, of course!), I simply settle for a printed thread.
• If, however, I want to make an interchangeable lens connection, I use a wider thread for the printed part and buy a step-down or step-up adapter for about five bucks (like this one, for example). So I can screw the adapter to the tube where it remains forever, and use the adapter's wear-resistant metal thread to attach the lens.
• On the camera side I usually want a connection that's not only rigid and interchangeable but even compatible to different (EVF) camera types. So I use a two-step adaption:
• In the first step I use a printed M42 thread to attach an adapter that features some outdated SLR camera bayonet (outdated SLR is important: Due to the massive back focal length of these cameras (especially Nikon!) these adapters are flat and cheap to produce, yet can be further adapted to any modern EVF camera body with full back focus offset compensation. An M42→Nikon AI bayonet adapter like this one costs just a little more than a dollar/euro, so you can buy them by the pound and permanently connect them to all the printed photo gear that may come to your mind. 
• In the second step I connect the SLR bayonet to a back focus compensating adapter that fits my camera (like this one, for example). These adapters are typically more expensive (between 30 and 50 dollars/euros), but I need just one per camera system since it can be connected and disconnected thousands of times without the risk of wearing out.
• What I never, never, never do is: use 3D printed bayonet connectors to connect to a camera. Yes, you find STL and CAD files for these all over the web, but they would not just be too unstable and unprecise to use. What primarily scares me is the idea of lots of plastic abrasion particles ruining my camera sensor beyond cleaning attempts. 3D printing is simply not precise enough to produce such parts. Accept that, or you will never get happy with your results…

As a rule of thumb, I still prefer machined metal parts if I can obtain them cheaply enough. But there are so many opportunities to find myself thinking “I wish I had an x to y adapter with a length of z mm" that the chance to simply print it myself is truly a blessing.