I'm passing this along from another list. It's interesting.
Morgan Hall gave this great post on forging, and tempering tiny jewelers
drill bits. I thought I had better copy it over here cause I think we may
have some fine workers that could use it.
apologies to the double dippers for the extra post.
Date: Tue, 23 Sep 1997 07:26:35 -0700 (PDT)
From: Morgan Hall email@example.com
Ron R. wrote:
It looks like you have lots of advice on the anvil so I will comment on
bits. I have both a post drill, and a drill press that I built
after some of the presses that predate post drills. it uses a brace
with a big ACME screw. I use the "spade bits" in it and I simply make
Ron, could you post a picture of this, please? I have a mental picture
of what's going on, but figure it's not quite right.
I second your notion of making your own bits. Some years ago I used to
teach jewelry making. (Patience please, there really is some
blacksmithing coming up here.)
Jewelers do a lot of pierced work. That is, drill a little hole, thread
the jeweler's saw blade through, saw an interior shape, remove the blade
and repeat until the piece is sawn to shape. A jeweler's saw is tiny.
Shapes are small. This means a small drill (say a #60 or so). 20 years
ago, a #60 drill cost about 80 cents, buying one at a time.
Students tend to break LOTS of these bits. For a while, I simply told
them to supply their own, figuring that they'd be more careful. Finally
I realized that most of them were simply learning fine motor control in
their hands and fingers, and were physically incapable of the control
necessary to work at that scale. I added a demonstration to my teaching
cirriculum -- making tiny drills. Here's about how it goes:
Jeweler's bench block (polished steel)
Jeweler's hammer (chasing hammer OK, I prefer rivetting hammer)
- Light the acohol lamp. Have the bench block next to the lamp.
- Holding the needle by the eye in the pliers, heat the tip to red
hot in the flame of the lamp.
- Forge it flat on the bench block. (if you can't do this in one
heat, you're moving too slow between heating and hammering.)
- Let the needle air cool.
- File the flattened tip of needle to the diameter of the hole and
shape the tip to a spade bit shape. Angle of filing creates the
relief for the cutting edges.
- Prepare a quenching container (I often used a soft drink bottle cap)
and put some 3-in-one oil in it.
- Heat the point to red hot and quench in oil before it loses color.
- Come right out of the oil and hold it in the alcohol lamp flame just
long enough to ignite the oil. Pull it back and let the oil burn
itself out. This draws the temper to just about the right point.
This little demo was really an eye opener to a lot of students. The
look on their faces when they could see two little curls of metal coming
off the point of their drill was amizing.
Guild of Metalsmiths