On 12/18/22 18:54, andy pugh wrote:
On Sun, 18 Dec 2022 at 17:54, gene heskett <ghesk...@shentel.net> wrote:
So, what jig or machine do you all use to sharpen drill bits in the
below 5mm categories?
I freehand them on the diamond wheel of the D-bit grinder.
And then try again if I have made it worse. :-)
Chuckle, BTDT in recent years. Embarrassing even
I still recall when I was a bench tech at Oceanographic Engineering in
'58. We were making a tv camera small enough to tow thru even small 4"
sewer pipes looking for leaks and such, had plans to rent it out to
municipalities to inspect systems. A whole bunch of Navy gold and silver
walked in the door one Monday morning and wanted to see what we had and
how well it worked in low light. Joe Petit, the head EE of the outfit
cleared out a bench drawer and very carefully laid our first one, still
in breadboard dress with parts hanging out, laid it in the drawer and
closed the drawer on the rg59 cable that was both power and output. The
autotarget took a couple seconds to ramp up the target voltage but it
about 2 seconds had a decent view of the wood grain in the drawer back
panel on the monitor, The admiral said sold, let go talk price in your
office. An hour later we had a contract to put two of them on the
Trieste for a dive into the mohole.
We hired a machinist, bought a 16"x72" LeBlond lathe the factory guys
spent two weeks making it bore straight holes. The Navy gave us drawings
for the camera cases, and quartz windows for the camera to see out of.
The drawings started with a bronze rod 8" in diameter and 3 feet long.
When the bronze arrived, the machinist got a little motorized brass disk
out of his tool cabinet, put a couple drops of diamond dust in oil on
top of the disk, stuck a fresh stick of HSS in a holder that had quite a
few holes at various angles drilled thru it. He fooled around half an
hour dropping that jig over the central guide post until the tool was
sharpened. I was as usual curious but each one of those holes was made
at an angle that properly shaped the tool. And I was very impressed when
he finally put it in a boring bar to drill the last cuts of a 2.75" hole
thru the center of that ton+ of bronze. The extra .25" was what they
calculated would be enough for the external pressure of about 18,000 psi
at the bottom of the mohole.
They both worked, and the rest of this story is in the history books.
We needed healthy pan and tilt gizmos, so we milled the tops off a pair
of Halomar units, filled them with light oil, drilled holes in the top
to let the pressure in, putting a rubber gasket between the oil and the
sea water, but should have pulled a vacuum before oiling them. Trapped
an air pocket in one of them and the rubber gasket was pushed into the
gears, grinding a hole in it, but it worked ok anyway for no longer than
they were on the bottom. Some might say I stretched the truth a bit, but
I literally had fingerprints in those two cameras that went down in the
mohole the first time.
Cheers, Gene Heskett.
--
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.
- Louis D. Brandeis
Genes Web page <http://geneslinuxbox.net:6309/>
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