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Burr is not spinning true

I would greatly appreciate some input regarding a problem that
occurred suddenly with my flex shaft hand piece.

I have a Grobet hand piece that is essentially a knock off of the
Fordom #30 hand piece that is about two years old.

The other day I was using it and noticed that the burr I was using
was not spinning true.

I thought that I must have dropped the hand piece on my bench with
the burr in the chuck, thus slightly bending the burr out of true. I
tried several other new; never before used burrs with the same
result, therefore I think the problem is in the hand piece rather
than the burrs.

I have tried opening and closing the Jacobs chuck several times and
looking into the chuck for obstructions in the jaws and found

I am a hobbyist jeweler/knife maker so I do not subject the hand
piece to the rigors of constant production work.

I am very interested if anyone has hade a similar issue with a hand
piece and if so is it correctible.

I know that this is not a very expensive tool in the grand scheme of
things, and I could easily buy another; but right now I would rather
put my money into finding some very nice ox blood corral.

Scott Damschen
Pima College
West Campus Plant Manager
Tucson AZ

Before you blame the handpiece, Scott, try putting an eigth inch or
so drill bit in the chuck and see how it runs. Burs are notoriously
poorly made now and I often find runnot a problem with them.

If the tip of the bit is wobbling around then the handpiece is the
problem and, as you say, probably the better move just to replace it
although there are people around (I’m sure you’ll get names in
response to your post) who can fix it.

Les Brown
L.F.Brown Goldwork

Hi Scott,

One possible cause is that your handpiece’s 3-jawed chuck is no
longer seated properly in the handpiece housing. Occasionally a
handpiece will get dropped or wacked just right to knock the chuck
off its seat. This will skew the chuck and make the burs wobble. You
should send it back to the manufacturer to get your handpiece back
to running true. They have the proper jig to seat the chuck, anything
else will give you partial concentricity.

Mike Zagielski
Foredom Sales Manager