Originally posted by dcshooter I have seen conflicting reports as to whether this lens ever came out in an m42 version. If yes, then do yourself a favor and sell the K and buy the m42. The headaches entailed in switching out a mount will far outstrip any money lost in the transaction. Otherwise, look for another Tokina m42 lens of the same vintage. While it might not be a 1:1 fit, the rear mount may use a similar screw configuration and be easier to shoehorn on. Alternately, buy a T mount to m42 adapter and start working on your lathe and milling machine skills. Also, try to avoid any mods to the lens barrel or original mount, since you will want to be able to reassemble it if you ever want to resell it in original condition.
I have plenty of K-mount bodies and another copy of that lens. It definitely exists in M42 (saw it go in fleabay) but, alas, very rare and extremely expensive.
Comparing it to other M42 Tokinas the screws holding the mount are in the same place and the mount itself seems to occupy a similar amount of length. My idea was to try to get the mount from an otherwise defective Tokina M42 lens and try to fit it. If it doesn't fit, the K mount can easily be put back. But I was hoping someone out there would have tried this already...