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View Full Version : Fitting a face plate - need an adapter



jason.weir
04-07-2013, 09:06 PM
my SB 14 1/2 has a 2-1/4-6 spindle thread - somewhat rare when looking for tooling. I bought a faceplate but it has 2-3/8-8 threads any suggestions on adapting it.

Jason

danlb
04-07-2013, 10:07 PM
Unfortunately you went the wrong direction when choosing an alternative mount. The hole is bigger than the major diameter of your spindle thread.

The only thing I cans think of is to bore it out and plug it so you can cut fresh threads.

If you buy a faceplate with a plain 2 inch hole or one with a mount 1 7/8 - 6 you will be abler to bore it and cut new threads.

Dan

Dr Stan
04-07-2013, 10:18 PM
The 14 1/2 SB I had was also one of the odd balls with 2 1/4-6 spindle threads. At the time I also had a 9" SB which allowed me to bore & thread the adapters for the 14 1/2 which I made from castings from SHARS. I just left the adapters in the 4 jaw of the 9", unscrewed the 4 jaw from the lathe and tested the fit on the spindle. I could then screw the chuck back on the 9" and still have registration and continue cutting the thread for the adapter until it fit.

If you have access to another lathe this should also work for you.

Forrest Addy
04-08-2013, 01:31 AM
I'm a believer of consumable faceplates. Ones you drill and tap (or weld to) for each job. Find a round hunk of 1 1/4" plate that just clears your ways. Drill in the ceenter to clear for a piece of all-thread you pass thru the spindle to pull it up to the face of a chuck with the jaws taken out. Face to clean up and clean up the OD. Flip it over, center it up and machine a shoulder the 4 jaw chuck OD x 1/2" for a jaw grip. Remove the all thread restore the jaws and chuck up your new faceplate.

I usually rough set up odd shaped faceplate jobs on the drill press table so I can drill and tap where needed, clamp the work then chuck it up in the lathe.

But this doesn't answer your initial question. Bore out the old threads to a minor dia for 2 1/2 - 12, bore new threads to suit the plug you previously made. LockTite the threaded plug in place and bore it to suit your lathe spingle nose. Oh, make a spindle npse thread gage before you start.

big job
04-08-2013, 05:43 AM
One of my lathes also is oddball. Quick and dirty I just chuck up a drill press
table, Instant faceplate.

gizmo2
04-08-2013, 09:12 AM
Just an idea, never tried it. You have a four jaw? You might be able to take out the jaws and make four plates that fit the slots, tap the plates for something handy. Drill the faceplate and bolt it to the front of the 4 jaw, indicate it in, then you are free to machine the bore. The set up would take awhile, but you could do it on your machine.

jason.weir
04-08-2013, 09:16 AM
Say I thread the plate to 2-5/8-6 (min dia 2.387") and fit a shouldered plug (with bearing retainer loctite) and then bore & thread the plug to 2-1/4-6 (maj dia 2.247") it gives me a minimum wall thickness of .140" - going with Forest's advice 2-1/2-12 (min dia 2.378) gives me a minimum wall thickness of .131" - will either of those be enough wall thickness and which thread pitch would be stronger?

Thanks,
Jason

jason.weir
04-08-2013, 09:18 AM
Just an idea, never tried it. You have a four jaw? You might be able to take out the jaws and make four plates that fit the slots, tap the plates for something handy. Drill the faceplate and bolt it to the front of the 4 jaw, indicate it in, then you are free to machine the bore. The set up would take awhile, but you could do it on your machine.

I think I can hold the plate in the 4 jaw - I'll try to get some pictures up of the process as I go forward - I have to order a bigger boring bar and find some suitable scrap for the plug...

-J