I found making plug gauges of smaller diameters way too much work, so I
started making the handle out of 12L14 knurled to suit, drilled holes into
each end, then crossdrilled and tapped for setscrews to hold appropriate
flatted pieces of either drill blank, or reamer blank. One of them is
supplied with plus tolerances, and the other is supplied with minus
tolerances. By choosing what I need, along with metric sizes available, I
have been able to all but eliminate scratch making most of the gauges we
use. Depths for hole testing can be established by grinding a V ring around
the blanks at the proper depth on the "go" end. It's heartbreaking to spend
a lot of time on a scratch built gauge, then have someone drop it onto a
concrete floor.

RJ

--
"Have no one say it, and say it to your shame, that all was well here, until
YOU came."




"Harold & Susan Vordos" wrote in message
...

"Jeffrey Lindemuth" wrote in message
...
I want to make a plug gauge using O1 tool steel. I am going to harden,
grind and lap the gauge and knurl the handle. So if I harden the entire
piece, how do I get the scale out of the knurls? Or do I heat the entire
piece, only quench the plug end, let the handle cool slowly keeping the
handle annealed, remove the scale and knurl? Or do I not have a clue
what
I
am talking about?

Jeff Lindemuth



If I was making the plug gage, and I didn't have a controlled atmosphere
furnace ( which I don't), I'd bead blast the entire gage after heat treat,
just before grinding. I'd heat treat the entire gage, not just the plug
end. Bead blasting removes all the scale and leaves a very pleasing
finish. All depends on the size of the media you use, of course. Very
fine sand (aluminum oxide, really) does a bang up job, too.

Harold