On 2010-03-05, Louis Ohland wrote:
Got a reply from the chuck manufacturer (they made the chuck and adapter
plate). They want me to return it. The bolt circles ain't raaht.
O.K. If all from the same maker, yes it is certain that they
are not right -- not just that the backplate was designed for a
different chuck.
I measured the bolt hole spacing with a pair of centerline points and
was able to reach the bolt hole passage inside the counterbore on top.
O.K. Good enough.
When my first attempts to assemble the chuck and plate didn't pan out, I
started to measure the bolt circles. Remember Sesame Street, "this one
is like the others, this one doesn't belong"?
Actually -- I was too old to watch it when Sesame Street
started, and never had kids to watch it with.
The thread gauge was rock steady. It had full contact on all teeth, top
to bottom.
O.K. Good enough -- but this still leaves the question of why
it is behaving like a slight thread pitch mismatch (the three turns and
stop is typical of that). Did you mention that to them as well?
Perhaps the backplate has the metric thread instead of the spindle.
And you probably should also try measuring the pitch diameter of
the spindle thread. Do you have a set of thread pitch diameter
measuring wires? If so, look up the right ones to use for 8 TPI, and
measure over the wires and apply the correction from the information
sheet with the wire set -- or look it up in _Machinery's Handbook_,
which will also tell you how to calculate the right correction factor
for wires which are close but not quite the supplied size for 8 TPI.
I do have the longer bed lathe, the Zangzhou Supermachine Company Bench
Lathe CQ6128AŚ660 http://www.yangzhoumachine.com/e-cp-7.htm shows a
550mm as well. Does not even mention spindle thread.
Interesting .
Funny, one of the messages on the home page was "Our Pinnacle: Customer
is Our God", you don't see that every day.
And if they treat you right, then this suggests that this is the
truth. (Or is this the lathe maker, not the chuck?)
Good Luck,
DoN.
--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. |
http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---