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View Full Version : 5/16 x 32 thread, or something else?



andy_b
07-21-2008, 11:08 AM
i have a 1935 South Bend 11" lathe and want to replace the tiny oil cups on the spindle bearings with some larger drip oilers (the kind with the sight glass). the original oil cups seem to be a 5/16 x 32 thread. according to my thread pitch gages, it is definitely 32 tpi. was South Bend using any strange English or metric threads back in 1935?
the reason i ask is because all the oilers i find seem to be no smaller than 1/8 pipe thread. there is enough meat to re-machine them smaller, but i just want to be sure what i am machining them into before i do it. 5/16 x 32 dies don't seem to be available so i'm just wondering if that is what the actual thread is.

i guess another option would be to open the spindle bearing caps up to take the 1/8" thread, but i hate to make any mods to an old machine that can't be reversed.

thanks,

andy b.

SGW
07-21-2008, 12:40 PM
5/16-32 is a NEF (National extra fine) thread. Taps and dies are available for it. MSC www.mscdirect.com or Travers www.travers.com ought to have them, but if they don't these guys http://www.victornet.com/cgi-bin/victor/subdepartments.html?did=100&id=tuEidYgd definitely will.

Your more general question, did South Bend use "strange" threads...yes, they did. The gib adjusting screws on my 10K cross slide are 10-28.