Chesapeake Area Metalworking Society
Review of 27 March
Mason District Governmental Center
6507 Columbia Pike
Falls Church, VA
We managed 18 folks at the March meeting, counting a guest, Jim Schwitters, from Fayetteville, NC.
After a little gentle prodding, Dave Welser got up and started the meeting.
The main program item
was by Don Nichols who showed us a
Dumore #21 precision
drill sharpener for small drill bits. By small, we mean 1/4" down to #70. He had
acquired this unit from Terry Elder and had restored it. In addition to the usual de-rusting,
cleaning, and lubrication, he also had to make own collets and magnifier lens assembly.
For comparison, Steve
Stallings had brought in a Rockwell
drill grinding jig
which is used with a bench grinder, but works on much the same principal.
There was also a SRD
brand drill grinder which used the
inside radius of
a cup wheel, instead of a cam motion, to provide the relief on the drill.
Don also brought
several rotational speed measuring
devices. Here he is showing
a Jones/Motorola mechanical RPM gage and one of the interchangeable tips for it.
Here is a close-up of the Jones gage itself.
He also brought a
General Radio strobe-o-scope which can
be seen to
the left of the Dumore drill sharpener in the photo above. This unit works
by adjusting the flash rate of a strobe tube to make the rotating unit appear
to stand still. The speed is then read from the control dial on the strobe-o-scope.
Our other program item
was a presentation by Tony Wikrent of
Nation Builder Books.
Tony told us about some of the many old texts about metalworking and about Lindsay's
many reprints of old books, manuals, and catalogs.
Tony brought along a
good selection of books and many of us
to take advantage of the convenient opportunity and purchase a "few".
We had a lot of show
and tell this meeting. First up was Dave
Bluett who told us
about a local company that was liquidating its shop and had many cabinets, vises,
surface plates, and some measuring gear for sale.
Then Chris Helgesen
had several items to show. First was a
large lathe toolholder
from our Tuckahoe museum project. He had used electrolytic de-rusting to clean it,
and gave a description of how it was done.
Next Chris told us
about a surface roughness gage that he
acquired. The picture above shows the stylus/probe from the unit. We
had an interesting discussion about how the unit works and alternative
methods to judge surface finish.
Then Chris told us
about a electromagnetic surface grinder
he was rebuilding. It was purchased with known bad guts and he was
investigating how to rewind the coils. Picture above is one of the two
coils from the unit.
Last, Chris had
brought in an optical centering scope
for use in a
milling machine. It works by aligning cross-hairs over the scribe
line, punch mark, or other feature on the workpiece. Here he is
showing the position of the scope above the work and describing
the angled metal piece that serves as a mirror to deflect light onto
the workpiece to make seeing the marks easier.
Chris's scope was in
need of repair and Tom Hubin, an optical
who recently joined CAMS, was able to help us with evaluating the condition
of Chris's scope and some others that were brought in as parts donors.
The meeting broke up around 11:30 PM and an unusually large contingent of
eight descended on IHOP for late night nourishment and storytelling.
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