Larry G. Nelson Sr. wrote:

> The problem with these is the tooling cost. The drills are OK but the
> special mills that outlinre the traces are expensive. They do last quite a
> while. The tools with a short life are if you want to do a board rubout of
> unused copper or another "outline" with the end mill to make a wider
> isolation path. The end mills in that size are expensive and wear out fast.

Actually, what you need to do is learn to sharpen the things. I used a
diamond hone and a "vision aid" to see the edge. Most of the machines
I've seen use a pointed bit, and the tip geometry is so simple that
sharpening is pretty easy.

-- Tom Rogers  Time Tech Inc.