Industar collapsible problem on Leica IIIc

<p>I have a 1963 Industar-50 collapsible that will not screw in all the way on my Leica IIIc (whether extended or collapsed). There's about a mm space between the lens flange and camera body after it is as tight as I dare, and, of course, it will not focus properly. Nothing is hitting anything on the outside. It threads in smoothly most of the way, and then stops. Any suggestions?</p>

<p>I bet there's incredibly little wear on this lens, because it probably never fit properly on a camera. The "Five Year Plan" production quotas didn't have a quality clause. Yours must have been made on a Monday (hangover day).<br>

Perhaps they goofed and cut the threads at 1mm pitch, instead of 26 threads per inch, which is what is correct. Canon did that on their first post-war screwmount cameras.</p>

 

<p>Thanks, John. FWIW, the lens fits fine on my Fed-2 and Zorki-4 (and has been used lots on the Fed), so I don't think thread pitch is the problem.</p>