"phi117" wrote in message
oups.com...
I just purchased Teknatool's Nova Midi Chuck to go on my Harbor Freight
lathe (HF 34706). My problem I'm having is that I can't get the chuck
to run true because the spindle is so long that the chuck can not
thread all the way onto the spindle and seat against the spindle's
shoulder. Without a good solid surface to seat up against, the natural
slop in the threads causes the chuck to run way out of true when the
lathe is running. I'm looking for any ideas that folks may have on how
to fix this.

The owner's 'manual' for the nova midi chuck clearly says that the
chuck must seat firmly against a solid surface in order for the chuck
to run true.

What I think I need is something that I can use as a spacer between the
shoulder of the spindle and the chuck. I need to take up about a half
an inch of space between the shoulder and the chuck. The lathe uses 1 x
8 threads on the spindle so the outside diameter of the threads is
right at 1". Also, the two faces of the spacer need to be VERY
parallel in order to allow the face of the chuck to seat squarely and
run true.

My initial idea was just to get a couple of washers with an inside
diameter of 1" that I could just slip over the spindle. A trip to the
Home Depot last night did not turn up any suitably sized washers in the
hardware section.

My second thought was to cut down a 1" PVC pipe coupling and use it as
a spacer, but I was unable to get good results from that. The coupling
was the perfect size, but I think the problem there was that I could
not get the ends sufficiently parallel on the cut, or the pressure from
tightening the chuck caused the PVC to warp a little. Either way, it
didn't work.

My next idea is to make my own 1/2" MDF 'washer' to go between the
chuck and the spindle shoulder but I'm worried that the MDF may dent
and cause the chuck to run untrue. I'm going to try this out tonight
and see how it goes.

Has anyone else had this problem? If so, what did you do about it? I
imagine that it must be a fairly common problem for people trying to
thread small chucks and faceplates onto a full size lathe. Does anyone
make some type of spacer ring with a 1" ID that is machined flat enough
on both faces to allow the chuck to seat firmly and squarely aginst it?

PS - I should probably note that the chuck does thread all the way onto
the spindle. Its just that when it does, the spindle prohibits the
chuck jaws from tightening fully. The chuck runs very smoothly with no
noticeable run-out when it is allowed to thread all the way down the
spindle and seat against the spindle's shoulder.

best answer would be to machineor have machined a spacer with a
1 x 8 threaded id and a shoulder with ad od equal to the "cavity" in the
back of your chuck
face off the front of the shoulder and you should be in business

HTH
Otto
t