j/b,
First, a Torx head is composed of two radiuses.
I'll call one the Root, and for a T10, that's about .020" radius.
The other is the Tip, and I don't know what that radius is, but for
argument lets say its the same as the Root.
There is no flat surface anywhere, it's a blended radius, from one to
the other. Also called a hexalobular.

If you use a slot cutter, and make straight edges, there will be very
high stresses at the Tip of your part, which will be resting on the
radiused section of the female receiver. Unless you use hardened
tool steel, it will deform, or wear very fast.

You could have a cutter made, but to find the exact shape you need to
buy a copy of ISO 10664, that provides the proper dimensions. (~$150)

Dave


On Dec 28, 1:59 pm, "jusme" wrote:
Gunner,

I just replied to MM that I had found another way.

Just as a learning exercise, why couldn't one chuck up a thin cutter in a
vert. mill, and cut a slot length-wise, index the stock and do the same
until all sides finished?

That must be fraught with Murphies but I have to ask to learn or try it to
learn.

Thanks for enlightening me on how hard it is.

j/b"Gunner Asch" wrote in message