On Nov 14, 9:00 pm, "Michael Koblic" wrote:
.....
*** I think the first decision that had to be made was to keep or not to
keep. Once the decision to keep has been made, all sorts of follow-up
actions are possible.

I suggest you keep it and learn its capabilities and limitations by
using it. If you eventually find that it's inadequate you will know
much more about what you really need, and what to look for.

Most of my commercial machine shop work has been for electronics and
optics, typically sheet metal or thin aluminum plates, rarely as much
as 2" high, and not usually requiring better than 0.005" accuracy. I
did some of it on a mill drill, some on my Clausing, some on a similar
Enco 100-5100 knee mill (http://grizzly.com/products/Vertical-Mill/
G3102), and some on a CNC Bridgeport. Generally if I set the head
height so a drill bit would almost reach the bed of the vise and used
end mill holders the mill drill would do fine, and I didn't need to
move the knee which would lose the Z axis zero on the EZ Trak CNC.

My home projects are more 3-dimensional and really need the extra
vertical travel of the knee. If I had the space I'd buy a Bridgeport.

Don't give up on the chipped end mill. It probably still works for
facing if you feed slower, since only one flute is cutting. The
chipped edge got shorter, not longer, and shouldn't scratch the work.
You can salvage a broken one by grinding the end flat, then copying
the 5 degree and 30 degree (roughly) angles of another end mill
freehand on a bench grinder or belt sander. The cutting edges should
slope slightly inwards towards the center so only the tips cut as you
feed sideways. One flute will of course be longer than the other and
do all the work at the bottom of the cut, so feed slowly.

If you need to mill a blind pocket with it, drill a starting hole
almost full depth and then run the end mill down it. You can deepen
the pocket slightly to reach finish depth by lowering the end mill
very slowly as you feed it sideways.

Once I have a replacement I use these degraded end mills for roughing
out deep slots and steps, and taking the first cut on mystery metal. I
can resharpen them correctly on my surface grinder and have been using
one pair of salvaged high-quality end mills for 15 years, saving the
new ones for finish cuts. I only hand-grind broken ones when it's a
rush job, someone broke the size I need, and a purchase order to
replace it takes 3 weeks. Small company shops can be even more
restricted than a home shop because both time and money are limited.

If you can't follow Harold's valuable advice on clamping, pad the
moving jaw with a piece of wood to spread the grip area and keep the
cuts light. I do the end facing first and use the cut-off remainder of
the stock to balance the vise.

Jim Wilkins