We discussed the case of high alloy (13% Cr, 9HRC) which harden itself
during threading and higher Vc is beneficial. Really hard having
leading screw without a special clutch.
Now question to the experienced guys:
1) I'm trying to translate "compound". Now having access to ftp look
's a angle scale or the name of an action?
2) What's your experience, benefits with top of the line inserts. For
example - renowned Sandvik, Iscar insert cost 10$ and more or less the
same on the market about 0.5$. Picture:
I looking for experience in everyday work and what means "more or less
the same" here. Everything except that top of the line insert is able
to work on very high Vc, mass productions etc. and with rare
materials. So the question would be: are Iscar or Sandvik or ... worth
of buying for typical materials and Vc200 RPM?
For D. Nichols - I've sent two mails - one came back and another from
another server wasn't bounced. This is my very first part that was
turned as a subject of this article - just in case:
"Compound" is a lathe term that means "the slide that can feed
the cutting tool at an adjust able angle to the lathe axes."
In your photograph the angle has been adjusted to be parallel
with the long bed axis of the lathe.
In this photo it is at approximately 30 degree angle:
At the bottom of the photo there is a large handwheel (partly
obscured) which moves the carriage along the bed.
Above that there is a smaller dial which moves the cutting
tool across the bed, the "crossfeed dial."
Above that is an even smaller dial which is the "compound dial"
which moves the tool in an angular motion. In the photo it
is sort of under my elbow.
Threading often uses the compound to infeed the tool because
it permits the 60 degree tool to cut on only *one* edge,
which simplifies the chip feed and also makes the final
thread form insensitive to the exact tool shape.
Check the files again. They should work.
Yes an insert has basically even 6 sides :)
In good tools you have the tolerances tight but resetting dials or not
is important is mass production. Any lathes with wear compensation so
far :) ? So no benefits of using renowned inserts ? You know the
fortune spent by Sandvik, ISCAR for research etc.
Yes - thanks a lot. I think I got enough advices for threads. What
left is a trapezium thread but everything in due time :)
Jack Zagaja - photographer, designer, programmer
free photoshop plugins, photographic assistance
opinions and much more ... email@example.com
They do, now.
Depends on whether it is positive rake or negative rake.
The larger of the ones in your photo appears to be a negative
rake design, with the addition of a special chipbreaker groove to turn
it into a positive rake at the cutting edge. That one, in the proper
holder, should be excellent. The proper holder mounts it at an angle,
so the bottom edge is somewhat away from the workpiece, leaving the top
edge to do the work. It can be turned upside down when all three
corners are worn, to provide another three -- assuming that the wear or
damage does not extend to the other side of the insert.
The two smaller ones are positive rake inserts -- see the taper
on the edges (one right-side up, the other upside down). That provides
the relief, so the insert can be mounted either totally flat (zero
rake), or with the edge angled up a bit, to produce a positive rake.
Those can only be used one side up, so they are only three sides. But
the angle makes the insert somewhat more fragile when doing heavy
cutting. And the fact that they are smaller overall adds to that
weakness. Those need an overhanging clamp to secure them.
The larger one can use either a screw, or a guide post and a
clamp, depending on the holder's design. Overall, a much stronger
Note, of course, that *none* of these are threading inserts.
(The larger one even seems to have greater than 60 degrees between
sides, so it would not work anyway.)
A threading insert has a different appearance. I'll attempt to draw on
side, and a part of the other two to show you what they look like:
\ ( ) /
The sharp spurs on the corners are what actually does the threading.
The rest is support only.
I find the inserts speed my work, even when not doing production
work. But I do grind my own HSS tools at need. The most recent example
was a set of inside and outside threading tools for Acme threads of a
size a bit too large for the largest insert tool which my lathe and
toolpost can handle.
Looking at the drawing in the other URL, I would include what
you have labeled the "angle scale" as a part of the compound. Your
arrow for "compound" points only to the dial and crank for the compound
feed. That, the ways, the T-slot in the top, and the angle scale are
all part of what is known as "the compound".
Looking again, I don't see a T-slot in the top of the compound
to accept the toolpost. Instead, there appears to be a single-sided
tool holder secured by a single bolt threaded directly into the top of
the slide of the compound.