I have a convertible Symmar 240 f/5.6 mounted in a Copal 3 shutter. i’ve tried mounting my Symmar-S version of the 240 5.6 lens into the shutter and it isn’t even close; the lens is much larger than the threads of the shutter.
I’ve read that the convertible Symmar actually mates to a Compur 2; when these lenses are mounted in a Copal 3, bushings are used to enable them to fit.
Can anyone confirm this? If this is true, can the shutter be returned to a plain Copal 3? I don’t really need the convertible Symmar - what I need is a plane-Jane Copal 3 (not 3s) shutter for another lens.
The 1964 Symmar brochure says that the 240/5.6 -- this is the convertible -- fits a Compur II 5/2.
OP, your 240 convertible's cells may have been made to fit a III or may have been adapted, as you hope, by threaded bushings. Three possibilities: bushings in the #III, bushings on the cells, cells direct fit in a #3. You should be able to decide which it is by examining shutter and cells.
You're a long term lurker here, so you might be aware of "the list." It has links to info on Compur shutter types and their dimensions. If you don't know what the list is, ask.