I just acquired a 500mm f/5.6 Century Precision Tele-Athenar lens with a t-mount for SLRs. The mount that is currrently on it is probably a Nikon t-mount. Set screws came out neatly, but the t-mount to flange threads are on VERY solidly. I am hesitant to force it, obviously. Can someone give me suggestions. The only thing I can think of it a set of flexible wrap-around wrenches (which would force it and possibly deform one of the ends) and Liquid Wrench (which tends to spead a lot once it gets going. Maybe lighter fluid lightly applied at the join of the thread. I want to be very, very careful about this. The base of the lens is pictured. At the end is a Nikon lens cap. Then the T-mount. The longer smooth length above the knurled part of the t-mount is the Century Precision flange that provides the t-mount thread. With the t-mount disassembled, I've got two basic smooth cylinders to unscrew from each other. I also am assuming that the t-mount unscrews counterclockwise (that is, normally).