T-mount stuck on lens

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).

Before doing anything else: try 2 wide rubber bands. It is amazing how much torque you get when the parts don't slip.

richard ide said:

Before doing anything else: try 2 wide rubber bands. It is amazing how much torque you get when the parts don't slip.

Click to expand...

Or indeed household rubber gloves.

Cheers,

R.

Jeff, Century delivered those lenses in Century mount. This is sort of a super T-mount, with a larger thread and longer back focus. They also sold adapters to other mount systems including T. When I had my 500/5.6 TA II rebuilt by Century I bought a T-mount adapter for it so that I could use it on any old SLR.

If there's just one adapter on yours it probably is a Century-to-Nikon F.

If I were you I'd call Century, now owned by Schneider, for advice. www.schneideroptics.com.

And if I had known better I'd not have bought mine or, having bought it, sunk so much money into a rebuild. After it was all good as new I got a tripod mount adapter from SRB for it -- more expense, but much less expensive than Century's own -- and shot with it. The lens is an achromatic doublet at the front of a long tube, not a telephoto lens, and it suffers from chromatic aberration, which manifests as color fringing.

Good luck, have fun,

Dan

Just to note,the Nikon mount is a "F mount" not a "T mount".

OK, It came apart

Based on many people's advice, I methodically took the t-mount apart. A total of 9 (count 'em, 9) set screws, and when they were loosened, the parts of the t-mount sort of slid apart. The Century Precision t-mount adapter flange (receiver) came off the lens, and then I had total freedom to work with two steel cylinders completely detached from any optics or mechanisms.

Ronsonol lighter fluid (Que-tip applied) soak came first. Then the rubber gloves (Thanks, Roger, they were in the camera toolkit, but I always regarded them as skin protection). Then Liquid Wrench. The again and again until bedtime came and I soaked the joint in Liquid Wrench overnight. This morning, the joint unscrewed.

Dan, as I understand, the Tele-Athenars were doublets, the Tele-Athenar II lenses were triplets (as if I understand the optics). You're right about the Nikon mount -- that's what the seller had used the lens on. I had been in touch with CP, and a very fine fellow who owns some of these lenses sent me scans of a full set of specs on the range of Tele-Athenars that were T-adaptable.