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05-21-2015, 06:07 PM   #1
Jake Mogel
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M42 screw mount

I really messed up. I stripped the threads on my 17 mm fisheye lens, trying to get an adapter ring on. Is there anyone who can fix the threads or have I just ruined a great lens????

05-23-2015, 08:50 PM - 1 Like   #2
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QuoteOriginally posted by Jake Mogel Quote
I really messed up. I stripped the threads on my 17 mm fisheye lens, trying to get an adapter ring on. Is there anyone who can fix the threads or have I just ruined a great lens????
If you could find a 42 millimeter die with the correct pitch, you couls chase the threads to clean them up. It could be done by hand with a swiss file, by a good craftsman. After cleaning up the threads, I would suggest mount a K-mount adapter permanently. I looked at my 17mm and the threads are very fine.
05-30-2015, 10:51 AM   #3
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QuoteOriginally posted by First Poster Quote
trying to get an adapter ring on
The ring is probably for a T-mount. The diameter is the same, but the thread pitch is different (0.75mm vs. 1.0mm).


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05-30-2015, 03:26 PM   #4
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If all else fails, find a 'for parts' one and do a rebuild with the mount part. The mount would usually survive whatever caused it to go out of action. But since the part withtthe mount is part of the lens housing it is distinctive on each lens - not like K-mounts which are a subassembly of the lens.

05-31-2015, 03:09 AM   #5
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Hi there - what are you mounting the lens too? A K Mount camera or other?

In any case, since you are adapting, I would suggest applying the correct adapter as best as possible with some blue? loctite or similar. A semi-permanent fix meaning that you will have to dedicate an adapter to the lens.

Yes, you will be altering the mount but at least it is functional for your system.

Beware the T4 adapters ......
06-01-2015, 12:51 PM   #6
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QuoteOriginally posted by Wild Mark Quote
Hi there - what are you mounting the lens too? A K Mount camera or other? In any case, since you are adapting, I would suggest applying the correct adapter as best as possible with some blue? loctite or similar. A semi-permanent fix meaning that you will have to dedicate an adapter to the lens. Yes, you will be altering the mount but at least it is functional for your system.
And dedicating the lens to K mount. If it is K mount general advise is to buy a genuine Pentax adapter.
06-06-2015, 08:41 AM   #7
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Get a K-to-M42 adapter. Maybe you can use the one that did the thread stripping.
Find a good machinist who can put the adapter in a lathe, center it very carefully, and skim the threads out until the damaged lens thread will just - I mean JUST - slide inside.
Glue the adapter on with an epoxy resin (Araldite is my favourite).
Be very careful that the lens is correctly oriented in the adapter when the adapter is in the camera body.
Now wait for the epoxy to set.
Then give it another 24 hours to get really hard.
Job done!

Geoff
06-06-2015, 05:00 PM   #8
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QuoteOriginally posted by Jake Mogel Quote
I really messed up. I stripped the threads on my 17 mm fisheye lens, trying to get an adapter ring on. Is there anyone who can fix the threads or have I just ruined a great lens????
As one has mentioned, careful work with some swiss files could get your lens back to work. For me, I would use one of those magnifying jeweler's hoods so I could see the threads.

And finding a donor lens to scavenge parts from is certainly another option.

If a suitable repair or part swap is not possible, the trimming and epoxy method may be worth the effort. But it would permanently render the lens dedicated to whatever mount is used. Also, one may have to exercise care when mounting and dismounting the lens and handling the camera after an epoxy repair. Given the epoxy would be holding fairly flat surfaces together, there would always be the possibility that the glued joint would fail.

Good luck, whichever path you choose!

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