Precision vs. "Regular" collets
On Jul 7, 1:36*am, "DoN. Nichols" wrote:
On 2010-07-07, Searcher7 wrote:
...
(Like I mentioned, the ability to flip the work around, center, and
machine it seamlessly to match the opposite half is what I'm after).
* * * * Then you want to turn between centers. *I don't think that you
will get seamless with *any* collet system.
...
If I pull a part out of the collet to test the fit and then put it
back in the same way to shave off a few more ten-thousandths there is
always a high spot where the bit rubs first. The new cutting pattern
is visible as a fresh cut part way around.
Reversing the work is the same, I can always see where the two cuts
come together, even if the difference in diameter is barely
measureable. This is on a good South Bend lathe whose spindle
indicates less than 0.0001" of runout.
A file quickly erases the pattern, at the risk of distorting the
cylindrical geometry. When that matters I use a good-quality pillar or
hand file and watch the disappearing tool marks as a guide.
Turning between centers works best for appearance, though the
tailstock on my lathe is difficult to keep aligned. It came from a
trade school where it received relatively little use but much abuse.
jsw
|