On Tuesday, 17 Dec 1996, John Loftin wrote:
> When I said "bore gauge," I did not mean "snap gauge" or "T-gauges."
Right. The "T-gauges" to which I referred are the spring-loaded locking
gizmos somebody reported buying for $25 or something. Mine are
Starrett, and I imagine a set is over $50 now, but I don't know. They
are shaped like a letter "T". The name also comes from their more proper
name of "telescoping gauges". The idea is that you set the locks snug
with the gauge askew in the bore, than drag the handle through the axis
of the bore. The telescoping part then retracts while the tools
automatically aligns itself to the diameter of the bore. Then you get
out the tenth-reading outside micrometer or the vernier caliper and
measure the gauge. Since the gauge measures at only two points, it will
not detect the classic three- or five-corner out-of-round condition
common in holes made with a twist drill.
> BTW, the 2-3" Mitutoyo I purchased measures "tenths" of thousandths.
> A very high quality tool. I used these extensively as an
> engineer over a "bank" of CNC machine centers.
Yes. I have found Mitutoyo to be very nice. When I was in the trade,
they had an 8" vernier caliper which was a bit handier than the typical
6". If they still offer it, I'd recommend it as a basic tool. I sold
all my stuff. All I have now is a truly crappy 1" mic and fairly decent
6" vernier caliper. And those Starrett T-gauges.
Phil
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