The focusing helical is from the Medalist, but the FD mount is from the defunct Tokina lens. Since the registration distance on the Medalist is much longer than the FD registration distance, it was no problem keeping infinity focus.

I use it occasionally, but I'm not shooting as much 35mm as I used to.

There is a LTM adapter to FD, but infinity focus can be a problem, depending on the lens. Enlarging lenses can work fairly well with this arrangement. You can focus adapted lenses with a bellows or one of the FD variable extension tubes (which are hard to find, but really neat if you can turn one up).

There's a lot of info on lens hacking on Bob Monaghan's website. I had an article on lens adaptations on at one time, but I think it's not there anymore. It might be on some internet archive somewhere (waybackmachine or some such).