Excessive Chuck Runout

My SuperNova chuck runs true on an old Delta lathe (1"x8tpi), but when a new adapter is used on a new Powermatic (1 1/4"x8tpi) the chuck wobbles. A new Talon has no problem on the Powermatic, nor does the faceplate sent with the lathe.

A second new insert from Teknatool did not fix the problem. When just the insert is screwed to the arbor and the setscrew secured, it will not run true.

Rick Smith posted a similar problem in 2007 on a Delta 1440, but my chuck runs true on one lathe, but not the other.

Thoughts?

Yeah, it's a bad insert. I assume your replacement came from the same store ... and the same batch of inserts which are probably all bad. This seems to be a problem with Teknatool that they occasionally have bad batches of inserts. I have a bunch of their inserts and haven't had any problem with any of them, but I have heard lots of people mention the same thing.

Try getting an insert from a different source so it will be from a different batch. You know the chuck is fine because it ran true with the Delta insert. You know the Powermatic is fine with the Talon. Find a good insert and you should be in good shape.

Your tests have proven it's the insert.

Very thoroughy troubleshot, I will add.

Make sure your new insert is bottoming out on shoulder of the PM lathe spindle. If not, it will wobble.

The Teknatool adapter may not have been machined deeply enough for the PM or it may have been just been machined poorly.

You might also try one of the nylon washers on the spindle behind the insert. I have a new 12" Don Pencil buffing mandrel that had lots of wobble when I first screwed it on my DVR xp. Almost all the wobble went away after I put a nylon washer on the spindle behind the mandrel. I know some folks claim the washers increase the runout, but it sure cured my issue.

I make my washers out of plastic in the recycle bin.
Milk containers-thin
Glad type food tainers-thicker
Cottage cheese lids-thicker yet

Expensive but worth it

Mike, Jim and Dick, I am using a washer (milk carton material) between the headstock and the chuck insert. Reduces the incidence of chuck locking on the arbor.

The insert is fully seated against the headstock; with the Talon, SuperNova chuck and SN insert alone.

Dick, as to the insert not being machined deep enough, I cannot answer to this as my machinist training is sore lacking. The set screw does engage behind the arbor threads when seated against the headstock.

Ken and Ryan, a note has been sent to the original supplier of the chuck in hopes they have an insert in stock. My current supplier is sending a 3rd insert and I am returning the 2nd, accompanied with a CD containing several video files showing the problem and lack of problem -- just for their information.

Thanks to all for the information.

Charles