nightjar nightjar@ wrote:

A broach would be the usual way to make an odd-shaped hole.

http://www.culvertool.com/Products.htm

shows some of the shapes you can make with a broach.

Yup that looks like the job... in fact the wikipedia entry
(http://en.wikipedia.org/wiki/Broach) explicitly cites making keyways
and splines on gear wheels etc.

Not a technique I had come across before though - Hence why I was having
difficulty working out how you would get an end mill in there ;-)

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/