"Bob La Londe" wrote in message
...
Alright... I've been using carbide tools in set screw tool holders
for years. I've made my own for smaller tools when I was using
nonstandard collet nose spindles for tools that were to small for
the spindle. I've also made my own solid one piece tool holders
with a setscrew.

I have to be honest. I've never really had an issue with using
carbide round tools in set screw tool holders, but I am told that
set screw tool holders "should only be used for tools with a flat."
I do put the tool holder in a fixture and tighten the set screw with
the maximum tool pressure I can put on a long arm hex key without
stripping the screw (and sometimes stripping the screw LOL).

So, is it what I have been told true? Should I only use tools with
a flat on them in set screw tool holders? If I do that then am I
reduced to finding a way to put a flat on those tools? How would
one go about that?

I'll probably ignore all that and just keep doing what I am doing,
but I thought I'd ask.

P.S. I use almost exclusively carbide tools except for drills. I
even have some carbide drills in sizes that see a lot of use. I
have a few HSS mills, but I rarely use them.

In my experience with mostly HSS, grinding a flat reduces mushrooming
on the end of the screw because it doesn't need to be as tight, and
the screw makes area instead of line contact.

If I can't easily surface-grind the flat or dog-point the screw on the
lathe, hand grinding them is usually good enough.

If you can remove a mushroomed setscrew through the center hole it may
not matter.