The other Topcon - very similar to the DKL mount. Aperture control is on the camera body.
Today it dawned on me that I had a broken Topcon body. Why not make an adapter from the original mount? Why didn't I think of that before? Well, in fact, I tried this with a Kodak Reflex with DKL mount, but no cigar. The mount is too intricately intertwined with other parts of the body that it was difficult to separate the mount with the aperture control intact. But, what have I got to lose? It didn't take long before sweet success arrived! The mount is much simpler than the DKL and aperture control stays unaffected after mount is removed from the body.
Gruesome body parts. The mount we want is on the right.
After the mount is removed, I JB Welded a 58-49mm filter ring (don't have a 58-52mm handy) to the rear of the mount, added a 49-52mm step up ring, and mounted the adapter to the very thin focus helicoid. Very unfortunately, I can't use my favourite Yeenon helicoid as the mount is about 2mm too thick. How I wish I had a metal lathe to shaved off these two millimeters. But, this will do in the meantime. The mount adapter is not perfect. the filter ring I glued/welded on is slightly jagged and is not completely flat, cause the left side of the picture to be slightly softer than the right side. I will need to find a better solution for this. It's workable for the time being.
UV Topcor 35mm f3.5 with mount on helicoid. Note the filter rings.
The other Topcors: Mount, 53mm f2, 35mm f3.5, 135mm f4.