- Joined
- Apr 29, 2019
- Messages
- 2,045
A way to make that shape.
For the punch start with a round bar in the lathe. turn it to .808 dia at the end and taper it about 20°. Now tilt it at about 15° in the mill and cut the big end flat. this will give you the cutting end of the punch in an ellipse that is .808 x .838. now take that part and place the cutting edge down flat and mill the other end parallel to the first cut and you will have a nice punch with about 5° of relief.
Now do the same for the die, start with a bored hole with the 20° taper getting bigger from the .808 dia. Tilt it on the mill to make the elliptical hole then flip it to make it back into a plate.
If you are using soft brass you will probably get away without heat treat. If it is a harder brass you may want to heat it up to a dull red and drop in oil.
Make a round punch for the holes and punch them first, have a pin slightly smaller than the hole to use a a centering guide to punch the ovel.
This will not make a perfect ellipse, but it will be within a couple thou.
For the punch start with a round bar in the lathe. turn it to .808 dia at the end and taper it about 20°. Now tilt it at about 15° in the mill and cut the big end flat. this will give you the cutting end of the punch in an ellipse that is .808 x .838. now take that part and place the cutting edge down flat and mill the other end parallel to the first cut and you will have a nice punch with about 5° of relief.
Now do the same for the die, start with a bored hole with the 20° taper getting bigger from the .808 dia. Tilt it on the mill to make the elliptical hole then flip it to make it back into a plate.
If you are using soft brass you will probably get away without heat treat. If it is a harder brass you may want to heat it up to a dull red and drop in oil.
Make a round punch for the holes and punch them first, have a pin slightly smaller than the hole to use a a centering guide to punch the ovel.
This will not make a perfect ellipse, but it will be within a couple thou.