Please, please, please don’t use Jet live centers on the Powermatic lathe

Woodshop
#1

Came in today to a Jet live center stuck in the Powermatic tail stock (ie I couldn’t get the jet live center out by backing out the quill). Right below the sign that says “don’t do this”.

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The jet live centers are too short to be extricated by turning the handle and drawing the quill back. Turning the handle back to pull the quill back will NEVER work in getting a Jet live center out – they are too short to be engaged with the stop inside the tailstock housing. The MT2 base on a jet center drive is about 1/2" shorter than the black center drive that came with the powermatic lathe and other center drives we have that work with the powermatic lathe (see sign above the powermatic lathe for a picture and description of each of the center drives we have).

To make matters worse – someone (perhaps multiple someones) tried to force the handle to pull the quill back which resulted in the handle coming loose and jamming the quill into the end of the lead screw. A hammer was on the lathe bed when I walked in.

Fixing this is a royal pain in the butt. The first thing to try is a bar to tap out the Jet live center (much like we take out center drives in the headstock). This works sometimes (about 25% of the time) but more often than not the head comes off the live center leaving the Mt2 base in the tail stock. The quill and lead screw have to be removed from the tail stock and taken to a vise for manual removal using large pliers. Then it has to be reassembled. Not a fun job and a total waste of an hour. This is the fourth time I’ve had to perform this major surgery.

And yes, I tried knock out rods to get the entire jet center drive out – they do not work on getting the entire jet center drive out, but are good at getting the head off the jet center drive. Apparently the outer diameter of the jet center drive is <= the inner diameter of the Powermatic tail stock. And yes the end of the MT2 base is hollow on a jet center drive which allows you to run a bar all the way through to take the head off.

Please, please, please don’t use Jet live centers on the Powermatic lathe, I’m begging you for the love of woodworking! Please review the sign for which live centers are ok and which are not.

7 Likes
#2

Think a sign on the barrel of the tail stock leading people to the wall sign might help? Thanks for removing it!

#3

I already added a temporary sign (blue tape and hand writing) - will make it nicer later.

#4

Thanks for making the post.

Brainstorming a bit, will the powermatic center work properly in the Jet Lathe with it’s longer taper?
I wonder if there is a universal option that can be institute so that the new and less experienced don’t have the option to make this mistake? If we are lucky and the powermatic works on both, replacing the Jet parts with powermatic or similar parts could save experienced volunteer hours on this difficult repair and possibly remove this problem going forward.

Thanks again for fixing this and leaving the shop better than you found it!

#5

Or if the Jet live centers are hollow could we press a short hollow pin in the back to make it longer but still have a way to knock the center off of the morse taper if needed. Downside is we would lose a little travel on the Jet tailstock.

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#6

Also, we could, in theory, tap the end and put a removeable screw in. But the Jet live centers were designed to handle the loads associated with 110 v motor and max 12" blank on a Jet 1221, I don’t think they were designed to handle loads generated by a 220v motor and up to 20" blank on the Powermatic Lathe.

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