C-mount to M39-mount extendable extension for Raspberry Pi HQ Camera

This is part of my attempt to create 8mm(R/S) / 16mm film scanner, where the two pieces will be connected and attached to a Raspberry Pi HQ camera (C-mount) and then a Schneider Componon-S F2.8/50mm lens (M39 thread).

Short design video from within Fusion 360: https://youtu.be/qwwfZ6v8VeU
Intro: https://youtu.be/i4KE87_ogm8

If you're interested in film scanners, I highly recommend you visit https://forums.kinograph.cc/
A big "thank you" to Matthew Epler and all the cool people on the kinograph forum for sharing their knowledge.

I found these tutorials helpful in making my design:
Fusion 360 threading: https://www.youtube.com/watch?v=aGWrFeu8Hv0
Fusion 360 knurled nut: https://www.youtube.com/watch?v=xHas0R5-6uc

Print Settings

• Rafts: No
• Supports: No
• Resolution: 0.05mm ULTRADETAIL
• Infill: 20
• Filament brand: Generic PLA
• Filament color: Black
• Filament material: PLA
• Notes:

I used 3DE Premium Pirate Black filament, and turned down the temperature for "Other layers" to 205 degrees Celsius, and changed "Elephant foot compensation" from 0.2 to 0.3

At 0.05 ULTRADETAIL it takes a long time to print, you can however use adaptive layers, and Prusa Slicer will figure out that it can print faster when there are no small details!

File explanation:

1. CMountToM39Extension-A-Bottom-Length44mm: Fits into a camera C-mount (1-32 UN 2A thread), allowing for any of the top extensions below to be attached. 44mm in length.
2. CMountToM39Extension-B-Bottom-Length24mm.stl: Fits into a camera C-mount (1-32 UN 2A thread), allowing for any of the top extensions below to be attached. 24mm in length.
3. CMountToM39Extension-C-Top-Thread45mm-Length73mm.stl: Top part ending in a M39 mount, and with 45mm thread for the bottom part, and a length by itself of 73mm.
4. CMountToM39Extension-D-Top-Thread30mm-Length73mm.stl: Top part ending in a M39 mount, and with 30mm thread for the bottom part, and a length by itself of 73mm.
5. CMountToM39Extension-E-Top-Thread30mm-Length43mm.stl: Top part ending in a M39 mount, and with 30mm thread for the bottom part, and a length by itself of 43mm.
6. CMountToM39Extension-F-CounterLockRing.stl: Counter-lock ring, which you first screw onto one of the top extensions, and then when you've screwed the top part into the bottom part, then you lock it in place with this "counter lock ring"
7. CMountToM39Extension-PrusaSlicerProjectWithSettings.3mf: Prusa Slicer project file with all the parts and with the settings I used already filled in (PLA, decreased PLA temp for other layers, increased elephant foot compensation, and set to print in ULTRADETAIL 0.05).
8. CMountToM39Extension-Fusion360Model.f3d: Fusion 360 model (I recommend right clicking all circular pattern featuress and suppressing them until you are done editing the model).
9. CMountToM39Extension-TestPrint.stl: Cut model of 5mm height, so you can do a test print and modify your printer settings until everything works for you.
10. Threaded-C-Mount-Connector.stl: The connector between the RPi HQ cam's C-mount (or any other camera with a C-mount), and the A or B part above.
11. CMountToM42Extension-X-Top-Thread30mm-Length43mm: Same as above number 5, but for a M42 mount instead of M39 mount.
12. M39-Cap: Cap for closing the extension tube's M39 opening

Possible combinations:
B+E: 42mm - 57mm
A+E: 51mm - 77mm

B+C: 72mm - 87mm
A+C: 72mm - 107mm

B+D: 72mm - 87mm
A+D: 87mm - 107mm

The top parts have a sunk-in ruler, which I painted with white nail polish to make it stand out.