I thought I’d write something for those who can use it about how and
why a bench pin is used. Conceptually, anyway - I’m not saying, “This
is how to work”. I saw a video lately where the maker was struggling
with the pin, and I visit college classes 2-3 times a year and see
the same, all the time.
It’s all about force. And the bench pin is not just a work surface,
it’s a three dimensional space. Drilling and sawing, two common jobs
on the pin, are pretty easy to understand. It’s the filing that uses
the pin to it’s best advantage.
Let’s suppose that you have sized a ring up by a few sizes, and you
have an oversized chunk of metal that needs to be blended into the
shank by filing. Let’s also suppose that your left hand (lefties can
reverse the hands all the way through - no doubt they’re used to
that) was run over by a car last month. Although it’s healed now,
it’s tender and can’t take much stress. You’re not going to use it
much, anyway…
First, file the inside. Either find a notch or make one in your pin.
Put the ring with the sizing down and put the edge away from you
against the notch. I make a triangle with my left fingers - thumb on
the front, middle finger on the back and index finger on top,
holding the ring down onto the pin surface. File it by pushing the
ring shank against the notch - all your left hand does is hold the
ring in place, and it takes relatively little force. Then do the
sides - hook the top of the ring against a corner of the bench pin,
with the sizing away from you. Hold it there with your left hand
under the bench pin. A single thumb press might do it.
File it on the far side, and you’ll see that the filing action
pushes the ring against the corner of the pin, where the ring stops.
All your left hand does is keep the ring from falling off.
For the outer edge, hook the inside of the ring over a corner with
the filing facing up, left hand underneath. Again, the filing drives
the ring onto the pin, and your left hand is simply holding it up
against gravity. You need to file a design into the shank, so you
hold the ring up against the front edge of the bench pin, so your
filing drives the ring into the pin, not your fingers.
It’s like a vise with only one jaw. The force of your filing is the
other jaw, and with a solid bench pin and proper technique you can
put the full force of your shoulder behind it. It doesn’t matter how
strong you are, your left hand simply can’t withstand that force.
There are millions of individual tasks, but the point is to use the
bench pin as a stop and to allow yourself to exert maximum force. And
thus get maximum work in minimum time. Almost always your left hand
is just a holder, not a source of any great strength. If you need to
use your left hand more than that, probably there’s something you
could be doing better, on and with the bench pin.