"Terry Coombs" wrote in message
...
F. George McDuffee wrote:

PAYDIRT ! Between you and Jim I now have enough info to build a
fixture to set the angles and index the EM's . Just made a boring
head , also put the finishing touches on a ball turner . I figger to
make as much stuff as I can to be self-sufficient as I can get ...
and the idea to use a die grinder was excellent , but maybe a router
with a speed control ? I can visualize a small surface grinder type
setup based on a Porter-Cable laminate trimmer .
--
Snag

When I salvage a chipped end mill I first rough it to shape on a bench
grinder, first squaring the end and then relieving behind the cutting
edges. I can hand-sharpen a two-flute well enough to cut, they are
easier than drill bits, but haven't tried to make the two edges cut
evenly since I can do the finishing passes much more accurately,
though slowly, on my surface grinder.

The workpiece on a surface grinder is literally caught between a rock
and a hard place, and if it shifts slightly and jams the wheel can
break. I don't grind more than 0.002" per pass and usually take
0.0005" or less. That makes the job very slow without roughing it
first on a more forgiving bench grinder. Also the surface grinder
heats sharp edges blue in an instant unless you take very light cuts.
This is more of an issue on planer blades than HSS endmills.

If the spindle you use has any end play it will round off the edge as
the stone passes off it and drops.
jsw