Nikkor-H 5cm f3.5 lens won't fit my Bronica S2. Why?

[httpwww.photo.netaj_ch]

From what I can observe, it seems the auto-stop down post that sticks out of the bottom of the lens is contacting the first couple threads inside the helicoid, preventing me from getting the 3 bayonet prongs deep enough to allow me to turn the lens and lock it on. Anyone ever heard of this? I see a shiny spot down inside the helicoid on the first couple of threads and that shiny spot (spots) line up with that stop down post extending out of the neck of the lens. I have removed that threaded post to see what I could see. It seems to have a wide spot on the post like a built in stopper/washer that only allows the the post to be threaded in just so far as that wide spot will allow. When I do try to tighten that brass post it causes the opening/closing of the shutter blades to stick. Barely loosen it and it fixes the problem. Any ideas? Wondering if someone may have worked on it and put in the wrong threaded post from another camera. Anywhere to get a replacement post other than a parts lens?

[peter_fowler]

Do you have access to any of the other lens to verify that's the problem ? Peter

[peter_fowler]

Any luck with getting it working ? Peter