How to remove lens cells from 360mm APO Ronar in black copal 3 shutter?

[OKAROB]

I have a 360mm Apo Ronar in a black copal 3 shutter. I can remove both front and rear cells but there appears to be a threaded insert/adapter to make them fit in a copal 3 shutter. It is these threaded inserts that I cannot remove. They barely stick above the rim of the copal 3 shutter's collar so getting a grip on them is very difficult. Does any one know if they are removable or did the manufacture use loctite or something on them? Appreciate any information /help on how to remove the threaded inserts, I want to stick my 480mm APO ronar cells in my copal 3 shutter. Thank You.

[Jason Greenberg Motamedi]

Years ago I removed a 360/9 Apo-Ronar from a Sinar DB lensboard and encountered the same threaded insert in the rear. I took mine to a local machine shop and they cut small notches into the insert and easily removed it with a lens wrench.

[mdarnton]

How about using a rubber ball as a wrench? Make sure the shutter and diaphragm are fully open so you don't hurt them, and don't get so extreme that you start shredding the ball, getting bits in the works. Something harder like a super ball and about tennis ball size. . . .

The general rule about this kind of stuff is that if you squeeze from opposite sides you make rings oval, and they bind in their slots, which is the why of slotted wrench fittings, all-touching rubber, or collett-type filter wrenches, none of which will distort the ring. Grabbing just one edge, fingers inside and out, works well on filters, but there's more to hold on to than you probably have in your case.

[Arne Croell]

Yes, rubber is right. Even better than a ball is a rubber stopper of the right size. Years ago I bought a set at micro-tools (http://www.micro-tools.com/store/P-LR-KIT/Lens-Ring-Tool--Kit-Gum-Rubber-10-Pc.aspx) and it has been quite helpful in removing, filters, rings, lens cells etc.

[OKAROB]

Hey guys,
Thanks, I will go the hardware store and get a hard rubber stopper and give that a try. They are all great ideas thanks.

[Struan Gray]

A kitchen store might be just as much help. One of those kitchen gripper pads for opening difficult cans works well. Rubber band it over the opening of a suitably-sized jar or sauce bottle, then just press evenly and turn.