Imagine, for a moment, that you have built a camera. Further, imagine that you desire to use a remote cable release to trigger the shutter. After excitedly purchasing your cable release, you notice that the threads are a strange and obscure tapered arrangement, a configuration not to be found on the shelves of your favorite hardware store. Using your new remote trigger cable is going to require adapting something completely ill-suited to the purpose (a standard M3 nut, for instance, only engages the largest threads). A tapered thread tap, perhaps? Ha ha ha!
Just try to find what you need on the Interwebs. Go ahead. I'll wait.
It's not out there, but, hopefully, this bit of data can solve your problem. This is intended to be a negative space to receive the cable release conical threads. Incorporated into another three dimensional structure, you can add a provision for a remote shutter to any thing conceivable.
This probably cannot be effectively 3D printed on a consumer-grade FDM machine (it's tiny!), but services like Shapeways can print at greater resolution/accuracy. Time will tell. I'll let you know. The B&W photo is a quad-sized test print that meshes perfectly. I now have a properly-sized SLS-printed product from Shapeways for your own homemade camera adventures - https://www.shapeways.com/model/1512877/shutter-cable-release-adapters-tapered-threads.html. Very affordable in White, Strong Nylon. See photos.
Additionally, I have included some double-sized parts (labeled accordingly). The original is so small as to have rendering issues at true size. Hopefully shrinking a larger object by 50% will preserve detail. Use your favorite CAD editor to customize and scale what you need. For some reason, Thingiverse is not rendering these parts, but they appear to be real STLs, available for download. Let me know if you have problems with these files.
This work is licensed under the Creative Commons - Attribution - Non-Commercial license. This license applies only to the files and documents available for download from the Thing Files section of this Thing.
All other related content (photographs, videos, and verbiage such as contained in "Description" or "Instructions" ) are excluded from this license. with all rights reserved, unless specifically available for download This notice constitutes a clarification, not a change, to licensing for this design.
The precise spec for the "Shutter cable release tip and socket" are contained in an arcane publication from the International Standards Organization, ISO 6053:1979. I haven't seen this document, and my working spec come from a decade-old, crowd-sourced, and empirically-derived exchange of information on photo.net.
"Thread pitch is 0.5mm. Thread length is 2.5mm. Overall taper angle is 30 degrees, or 15 degrees per side. Maximum thread diameter is 3.4mm..."
NEWS UPDATE: I have since found an American Standards Assn document that disproves the one assumption I made: The thread profile is NOT perpendicular to the 15ÃÂÃÂÃÂÃÂ° angle of the taper, but perpendicular to the central axis of the threads. See for yourself:
I fixed these discrepancies in a newer OpenSCAD file, called tapered_thread_V2.scad. Apologies if you downloaded the original file with the geometrical error.
I modified the OpenSCAD scripting from "Metric Screw Thread Library", thing:31363, by marcaxi. There is a certain elegance in his code, the mechanism of which eluded me for a while. Special thanks to aubenc also, for thoughtful consideration of this small (literally) project. I don't expect that you need to monkey with parameters much to generate usable threads, but feel free to adapt to other tapering spiral applications.
If I can help you use these files in your camera, I am at your disposal.
Finally, these files are freely available for download, distribution with attribution, but not for commercial purposes. I might be talking to you, China.