Removing a stuck retaining ring

I'm trying to open up a Canonet - either front or back - to fix a stuck shutter.

Neither the front or rear rings budge. I picked up a spanner kit from microtools with the hope that proper tools would help. No luck. I'm new at this so I tried removing the rings on a few other cameras just to be sure I wasn't making a mistake. They moved with little force so I don't think I'm missing anything basic.

I'm stopped when I realized that I was starting to strip the rings themselves. The camera is dead as it is but I want to step up the potentially destructive techniques slowly. I'm not looking to have the camera profesisonally CLA'd; I want to learn about this stuff and am saving the CLAs for higher end cameras.

Does anyone have tricks, suggestions or links with info they've found useful? I've looked around at solutions for a few days but haven't found anything yet. I haven't tried drilling yet (mostly lack of gear) but that is something I'm holding off on that for now.

Try a drop of 'Liquid Wrench' on the threads. Let it sit several hours, it should penetrate by capallary action. If this was a good camera, you would then have to clean it all off so it doesn't get into any other parts. It could affect lens coatings.

I just recently tried liquid wrench on a trio of set screws on a lens barrel & it worked really well. better than mucking them up.
Does the Canonet have the very narrow ring in the front, between the filter ring & decorator plate?
I've sometimes loosened them by inserting a pin on the spanner in one slot & beat(I mean tapped) it with a hammer.
OK maybe not a hammer, but a screwdriver handle or similar. Once it's loosened it should come right off.

Thank you both for the suggestions, I'll definitely give Liquid Wrench a shot.

John, correct on the narrow ring comment. I'll give that that a shot if the Liquid Wrench doesn't do it.

A mix of Bolt Off (similar to Liquid Wrench) and a little light tapping did it.

I still have one more ring to go buried deep inside the assembly before I'll know if i can fix the shutter, but it has already been a great learning experience.

After 23 years of doing camera reair I can tell you "NO NO NO ON LIQUID WRENCH OR WD-40, ETC." These will tend to migrate into areas not intended and really screw things up. Anytime a customer would bring in a camera (and I mean top of the line Nikon, Canon, etc.) and I smelled WD-40 I would tell them to throw the camera in the trash. Game over. Best bet for loosening retainer rings is a light application of acetone and really light! combined with heat from a blow dryer. The heat will cause expansion and contraction of the metal and loosen any adhesive. You may not even need the acetone. DO NOT get the acetone anyway near plastic surfaces!

pounder35

When I retired from camera repair 10 years ago the Canonet had already been uneconomic to repair for many, many years.
I think few repairers will have any experience of that camera.
Some general points to make here though...
Drilling as an aid to dismantling? Not in my experience.
Cheaper cameras weren't often designed with a view to future repairs - during warranty a replacement would be more common than a repair. On the rare occasions when money was no object (usually for sentimental reasons) and I've been persuaded to undertake a repair to such a camera I've found adhesives, barb-locks, welded plastic, aluminium screws (!) and other unspeakable atrocities. Once I found a lump of metal the only purpose of which was to add weight to a flimsy camera made to look like an SLR but which had a single element lens and a curved film plane. Had a name intended to be confused with Nikon no less!
I would suggest that if anyone wants to learn camera repair basics they buy a "spares or repair" decent make of SLR film camera and dismantle that. Nothing of much use will be learned from a cheap camera.
Apologies to Canonet lovers everywhere - or anywhere.

A few tricks I use on stubborn rings and ratty lenses. I found one ring on a like new modern lens 'locked' in place by paint or some other substance soluble in acetone. After dripping actone in the threads, the ring came off easily.

A second very very stubborn ring on an older 210mm enlarging lens was freed by heating the lens. I had to get it pretty hot, but the lens was otherwise nearly opaque and junk unless the ring could be freed. Thus the drastic measures. BTW the lens elements cleaned up very nice.