Hi William
I assume there are always exceptions, however that has been my
experience, (metal lathes having a groove for a setscrew, to keep the
chuck from unwinding) Of course the machining is done in forward and
no forces are applied to the setscrew, as for the chucks, when we
would get a new chuck, they where just plain back chucks and the semi
machined back plates, we'd have to machine those for the lathe and the
chuck, and yes drill and tap for a setscrew, of course no camlock
spindle noses.
I use the large #5 MT on my chuck so there is no unscrewing with that,
(I can flip it from outboard to inboard as I have only thread on the
inboard side, but taper on both sides), however if I had a 100/150
pound piece of wood starting to unscrew the chuck because my lathe was
stopping to fast, I would not expect the sliding resistance of a
tailstock to keep it from doing so, and a good setscrew would be a
more appropriate way of not having this happen IMO.
It would be nice though if all the wood lathe manufacturers could come
to a common position for a groove in their lathe spindles, but I guess
I shouldn't hold my breath for that.
Have fun and take care
Leo Van Der Loo


On Mar 6, 1:42 am, "William Noble" wrote:
leo is right as to the purpose. But he is mistaken in that not all metal
lathes have a groove for such a use - for example my metal lathe does not -
it has 2 1/4X8 threads but no groove - and the chucks that go with it don't
have the set screw either (and a little setscrew wouldn't do much against
the forces a metal lathe sees anyway)

My wood lathe will turn in reverse, and I have not had any problem with the
chuck unscrewing with a finished piece on it - so I'm not convinced the
little screw is needed - I have had the chuck start to unscrew if I brake
too fast with a heavy piece on the lathe (e.g. 50 pounds or 100 pounds), but
that's a different matter, and it's why I keep the tailstock in place when
roughing big pieces.

wrote in message

oups.com...



Hi Bob

The treaded hole is for keeping the chuck spinning off of the
headstock when you have a lathe that can turn reverse or one that can
be stopped quickly.
These lathes have a groove turned for the setscrew to tightened to,
metal lathes all have those grooves.
As your lathe does not have a flat groove, you probably don't need the
setscrew, but if you want to use one than the easiest way would be to
use a nylon/plastick setscrew, it will not damage the spindle thread,
or you could use a plastic plug between the setscrew and the spindle.

Have fun and take care
Leo Van Der Loo

On Mar 4, 2:44 pm, "Bob Daun" wrote:
I have used my chuck for quite awhile but I was just wondering why there
is
a threaded hole in the back end of the adaptor (the side facing the
headstock when mounted). The threads in the hole are quite fine but
there
is nothing in the hole. If I shine a flashlight into the hole I can see
the
threads from my headstock. Is this meant to use as and additional hold
down? I would hesitate to do that as it would ruin the headstock
threads.
Any thoughts on this?

--
Bob Daun

--
Posted via a free Usenet account fromhttp://www.teranews.com