On Fri, 2 Dec 2016 09:02:06 -0500, "Jim Wilkins"
wrote:

"Larry Jaques" wrote in message
.. .
On Fri, 2 Dec 2016 07:17:31 -0500, "Jim Wilkins"
wrote:

"Michael A. Terrell" wrote in message
news Jim Wilkins wrote:
...
The frames broke on these, near the die. I wore out a lot of
punches, before the frame died of metal fatigue. I used to do a
lot
of prototyping, with hand tools. Trimming fiberglass circuit
boards
to fit into a case was the worst for wearing out the tool.

I've worked at a few places, notably Mitre, that had good facilities
for both electronic and mechanical prototyping but that wasn't the
case at smaller startups developing some new idea on a tight budget.
I've nibbled, filed and sanded a lot of circuit boards to size
including the mechanical-fit models for the Segway balance sensor
assembly. At one place when the Dremel died I cobbled up a pump
drill
to finish a circuit board. Unlike a bow drill it applied no side
force
to the fragile carbide bit.

http://cart.occpaleo.com/stonetippedpumpdrill.aspx

For that price they could at least have found a prettier smoothed
river stone for the weight.

Do those rely on the inertial force of the spinning stone to work?
Wind 'em up, push down, and they spin until wound the other way.
Rinse, repeat?

Yep, push down, let it rise, push down...., while steadying the top
end with the other hand. It's less awkward and tiring than a bow
drill. Since it spins both ways a blunt spear point with flats on the
edges works well for the drill bit, and is easy to resharpen. You
could drill your first counterweight with a bow drill that doesn't
need one.

I wondered about the bit end. Dual flats, eh? Spoon bits are
interestingly shape, too.


http://www.lowtechmagazine.com/2010/...-machines.html

Cool article.


When I was little we moved into an 1830 house that had a chest of
those old "cordless" tools, which I used until I was old enough for
power tools. The tricky part was learning how to keep them sharp.

Ah, Eric Sloane: a great author with a bevy of very good books under
his wing. I have a copy of his _A Reverence For Wood_ and it's
marvelous. George Sturt wrote _The Wheelwright's Shop_, which is also
an excellent and detailed stroll through yesteryear.

As a Neanderthal wooddorker, I have either used, and/or made, dozens
and dozens of old tools like that, but never a pump drill. I made
fire with a bow drill just once, then immediately declared the end of
my enthusiasm for them. They're a lot of work. Those pipe augers look
like a whole lot more of the same. Ugh! Breast drills are a joy to
use, compared to pumps, bows, braces, Yankees, and little egg-beaters.
Ditto post drills.

And now, with metal, I'm finding much more ease with a drill press.
Who'd have guessed? A mill is a pain to set up, comparatively, but is
sure is accurate. Having come from a woodworking past, my time with
Glenn in his metalworking shop was a real eye opener on most fronts.
That's why I'm he to continue learning with all you good teachers.

--
We cannot but pity the boy who has never fired a gun; he is
no more humane, while his education has been sadly neglected.
--Henry David Thoreau