Question for a Machinist

No they can not. The 12mm is the major diameter of the threads. The second number is the pitch of the threads. . Lenses are very fine threaded .5 pitch means there is a thread every 1/2 mm or every .020 thousands of an inch .35 mm pitch is a thread every 1/3 mm (approx) or .014thousands of an inch. Not much metal left to play with. Hope this helps, MM
 
Yeah, I've only tinkered with a VMC and a few manual lathes, 
but something told me that the pitch was wayyy too close and fine to re-work..

I had to do something similar years ago, and it involved a few different steps.. 
[My project - Work done by a machinist friend]
1st the original threads needed to be completely turned/removed + a bit more material removed.. 
2nd rod had to be threaded then lathed into a 'sleeve' to take place of the original threads..
3rd the sleeve w/ new threads had to be brazed in place.
Granted it was a different application - the concept/procedure would probably be the same.
[And I don't think I'd chance doing 1/2 of that with something housing lenses]

Brian, I shot a PM your way - Just in case there's another option.. 
Cheaper than the GoPro option, but not 100% sure if the lenses are compatible

🙂 

Sam -

 
No they can not. The 12mm is the major diameter of the threads. The second number is the pitch of the threads. . Lenses are very fine threaded .5 pitch means there is a thread every 1/2 mm or every .020 thousands of an inch .35 mm pitch is a thread every 1/3 mm (approx) or .014thousands of an inch. Not much metal left to play with. Hope this helps, MM

I understand your explanation and unfortunately agree there just isn’t enough material to put it through the proper die I guess I’ll gust have to wait for what I want to be brought to market. 
 
The way that is done is not likely cheap, but then I could be wrong.

An adapter ring is "machined" with the two different threads as needed.

A metal or plastic tube with male threads to match the camera and female to match whatever one is trying to attach.

I may have male/female reversed as I do not know which the camera has to begin with.

One may be able to 3D print it for all I know!


 
Okay, a response from a real machinist. First the 12mm by .5mm pitch thread needs to be turned down. This can be difficult because the ring typically only has about a 1mm ring left at the bottom of the threads. Then a ring, with the desired thread can be machined. The new ring is pressed/glued onto the turned down surface. The ring would likely need to be made of metal to have sufficient strength due to the thinness of the ring. It would not be cheap to have someone do it, and probably not worth the expense. Now the Optics guy in me would also mention that the "focal length" of the optics are important too. Unless the focal length is the same, then you might run out of threads (in one direction or the other) if it has a shorter/longer focal length than the original. i.e. you won't be able to screw it in/out far enough to get a clear image.

Although this is an interesting thing to discuss, I would advise against the attempt.
 
Okay, a response from a real machinist. First the 12mm by .5mm pitch thread needs to be turned down. This can be difficult because the ring typically only has about a 1mm ring left at the bottom of the threads. Then a ring, with the desired thread can be machined. The new ring is pressed/glued onto the turned down surface. The ring would likely need to be made of metal to have sufficient strength due to the thinness of the ring. It would not be cheap to have someone do it, and probably not worth the expense. Now the Optics guy in me would also mention that the "focal length" of the optics are important too. Unless the focal length is the same, then you might run out of threads (in one direction or the other) if it has a shorter/longer focal length than the original. i.e. you won't be able to screw it in/out far enough to get a clear image.

Although this is an interesting thing to discuss, I would advise against the attempt.

Agreed (also a machinist here).

A good machinist could potentially turn new threads into it as you asked, but there would be a lot of cross-cutting through the existing threads and the metal would be substantially weakened from the loss of material. I would simply advise against it to be honest.

PT