"jim rozen" wrote in message
...
In article , Harold and Susan Vordos says...

My point in
getting you to try chip breakers is to learn about them and have them
firmly
entrenched in your mind, so when the need arises you don't have to go
through the learning curve.

Something I never did. LOL. Might be time to investigate, eh?

It's one of those things that you can go a life time without and swear it
makes no difference.. Bottom line is how much you expect from your machine,
your setup, your ability. I've always carried a definite edge over others
because I cared enough to learn early on. You're likely to find someone
that has the opinion that it doesn't matter. I think it does. I may
sound like an ass, but I can tell you all I need to know about a guy's
ability on a machine by looking at his lathe tools. When they look like
they've been gnawed out by a gopher, I rarely expect anything of substance
to come from the person, and I'm rarely disappointed.


I seem to recall teenut saying something about the chipbreaker
groove on a HSS tool could be done with a tiny cutoff wheel
and a die grinder.


I don't claim to be teenut, but I sure agree with him in this instance.
However, I don't limit myself to that. I can hand grind the vast majority
of my chip breakers using the corner of the wheel. Only when I get involved
with tricky form tools do I usually turn to anything else.


Understand that some aluminums cut without making strings. It's the
nature
of the material. Amongst them are 2024 and 7075, each of which will
gladly
cut string free under the right conditions, including the absence of a
proper chip breaker. 6061 is another story, and is generally more than
happy to generate strings, although generally very easy to control.

6061 is like turning silly putty. 2024T6 is more like steel than
aluminum. I love that stuff. Too bad you can't weld it.

It is a pleasure. During the period that we built the missile, and shortly
thereafter, it was the only choice of aircraft quality material we used. My
first introduction to 7075 was when I had already started my business and
had bid on some helmet gun sights for helicopters. Needless to say, I was
impressed. While you claim 2024 machines like steel, 7075 really does,
and emulates it in tensile strength. I liken it to leaded steel in how it
machines.

One of my favorite memories of being self employed was building a wave guide
for Univac. They never came in large quantities, sometimes as many as four
or five, but more often than not, one at a time. They were made from 2024
T351, a real pleasure to machine. Inside the guide a double ended plastic
component that came to a .005" flat end (wedge shaped) was installed, held
in place by four pins, also made of the same plastic. The job brought out
the best of my ability, with it's tight tolerance and exacting demands for
generating the proper configuration of the plastic insert.


... I use a
square tool block (my choice) so I shim all my tools. You get used to
having a small box of shims handy and it takes almost no time to set up
your
tools. You get to the point where you can pick up a tool and know what
shim
is required to hit center. I use anything for shims, including
strapping
material, which comes in a myriad of thicknesses. Old feeler gages are
fine, too, just expensive. And then there's always shim stock!

This is one reason I avoid back rake - because it means that sharpening
the tool requires resetting center height.

Not a very good reason, Jim. I'm the first to step forward and suggest
that you can machine with or without rake, with or without a chip breaker,
but the best work comes from the proper combination of each. It really
jumps out at you when you have more than a couple parts to make. You've
done yourself a disservice, something you'll slowly come to understand. I
guarantee you, your tools don't cut nearly as well as they can. Chip
control is as important as chip generating.

One thing I don't use is a tool rest. Never. Not for grinding tool bits.
They get in the way and restrict your ability. You likely won't be able
to
do that at school, but keep it in mind for home use. Have a special
grinder
that you use exclusively for sharpening toolbits, and have it mounted
such
that you can stand erect and grind at a comfortable level. It takes
some
getting used to, but once you master it, you'll never go back to a
conventional pedestal grinder for grinding toolbits. Knowing how to
properly dress the wheel becomes quite important when you grind this way.
It must run smooth and true, for it becomes your reference point.

Toolrests are OK for roughing stuff out, but I agree that 90 percent
of the lathe tool grinding I do is offhand, no rest. You have to be
able to get the angles right. Good lighting is vital. My grinder
is tucked away in a far corner of my shop, to keep grit off the machines.
The lighting sucks there, it's one more of those roundtuit items.

Jim

Chuckle! All in good time, eh Jim? Just don't let your entire life time
slip away, putting up with the bad setup as it is. It's almost impossible
for me to properly sharpen tools right now, what with our living in the
shop. My (rough) grinding section , roughly 30 feet from my precision
machines, happens to be the cloths drying station while we're living here,
so my grinder isn't properly set up. Of all the things I can't use as
desired, I miss it more than any of them. Especially the diamond wheel,
for touching up brazed carbide tools. I'm still a strong believer in them.
Old habits die hard.

Harold