Stuck adapter or M mount ?

[srtiwari]

Just bagged a Summarit 5cm f1.5 in lovely shape. The seller on EBay had indicated that he thought it was LTM with an adapter (rather than M mount), but did not want to turn it too forcefully to avoid damaging it. To me it looks like a stuck adapter, but cannot turn it at all.
Any easy way to- a) tell if it is M Mount rather than an adapter, and, b) How one might try to remove it safely- (WD40 sounds way to crude, and some will likely leak in.) ? 😱

Could someone more "handy" than me at this, please advise ?
I can provide pictures if that would help...

 

[karlori]

Stay away from WD40... That thing ruined enough good lenses and cameras in its time.
I unscrewed my voigtlander when it got stuck by mounting the lens on one parts/broken camera that i have pre heated and holding the lens in place while rotating the camera body...

 

[Graham Line]

Did you check for locking set screws?

Sometimes you can loosen adapters by freezing a lens and then twisting the adapter off using either a body or back cap with the internal gripping lugs. A tiny tiny tiny amount of very thin oil applied with a toothpick tip and allowed to sit for a day or two might help.

 

[crispy12]

Stay away from WD40... That thing ruined enough good lenses and cameras in its time.
I unscrewed my voigtlander when it got stuck by mounting the lens on one parts/broken camera that i have pre heated and holding the lens in place while rotating the camera body...

This is the method quoted by voigtlander for their own LTM adapters. Works very well. If you're unscrewing the lens, make sure it's not in the locked position to avoid damaging the mount assembly, just in place but not locked (clicked in)