Opening tool for M42 adapters

[hoanpham]

I have a pentax M42 adapter on a Takumar, but it got stuck really hard.
I saw some 3rd party M42 adapters on ebay that have an opening tool/key.
Can anyone recommend a good one?

thanks.

[peterqd]

Hoan, have you tried unscrewing the lens while the adapter is fitted in the camera? Always works for me.

[hoanpham]

Thanks. I have a film body faulty for this

[Aanything]

Usually the rear lens cap of my minolta AF lenses does the job, but I don't know how pentax adapters are.

[elliott]

The tools with the cheap ones on eBay are for removing the adapter from the body. I remove the clip from mine so they don't stay in the camera. I use a lens cap as a wrench to remove them from lenses.

[hoanpham]

It's still too hard. I might dstroy the lens with force.

[visualopsins]

Keeping lens cool, warm only the adapter (so it expands) might help to free it...

A drop or two (only a drop or two) of penetrating or wintergreen oil on threads might help too.

Try leather work gloves to get strong (padded) grip?

[hoanpham]

The previous owner had a super glue drop in it.
I try now to loosen the glue strength with pure acetone.

Anyone experience acetone use? like how long can i expect before the glue might take to break down?

That's a good idea to heat up the adapter. I will try to combine acetone treatment and solder iron.

[philslizzy]

no acetone!! can harm acrylics in the lens and lens 'glue'

[Lloydy]

I think you can buy a special Superglue solvent ?

I had a completely wrecked ME Super which I dismantled, basically to see how it worked. But I kept the front plate and lens mount completer and I have used that to force off a stuck M42 adapter from a lens. The lens is likely to be strong enough to take considerable force, and it doesn't matter if the camera front plate gets forced as I keep it for this kind of thing. But, I didn't do any damage to either of them when I forced the adapter off the lens and I had the camera front plate clamped in a vice and both hands on the lens - a Vivitar 28 if I remember rightly.



It's a useful bit of kit. I alsu use it as a drill jig to make a small hole for the Pentax locking pin.


( That picture is posed, I do take great care to keep bits of swarf out of the lens )

[hoanpham]

Update:
I gave up with acetone treatment. Tried 1/2 drop on the mount, repeat many times, but still not able to remove.
The lens+adapter is mounted on a defect pentax body, that had been ripped off for most parts, as opening tool to give a better grip.

I still hope that aceton treatment can slowly release the glue, but that too is risky if I spill on the glass.
It's still working fine when using with a pentax body, so I let it as-is.

---

That DRILL looks overkill for the task
May be I should try

[visualopsins]

Is S-M-C or SMC Takumar with second tiny pin (separate from diaphragm pin) on mount? Adapter jammed by tiny pin?

(I sent your adapter )

[hoanpham]

Thanks a lot for the adapter

No it's not the second pin that cause problem.

It's a pentax M42 adapter that had been glued into a m42 lens.
I drilled away the metal piece that lock the lens in place and it won't stuck in a pentax body.
All the effort is to undo the glue and turn the lens back in m42 state.