On Thu, 02 Aug 2007 22:52:58 -0400, Kirk Gordon
wrote:
Proctologically Violated©® wrote:
Awl--
I'm starting to get involved with making low-end turning tools, and have a
few Qs regarding how people actually use them, and relative merits of
design.
For example, so far I've made simple left-hand cutting tools, with
triangular screw-type inserts, .600 vertex-to-vertex, about 1/8 thick.
Now I"m making boring bars with clamp-type triangular inserts.
snip
Thoughts?
Dude!
You gotta buy some of these tools and use them, before you get too
deep into trying to reinvent things.
snip lots of good advice
Do diamonds, Dude. Dey's delighful!
KG
==============
Kirks's observations are spot on.
In high volume commercial use, competitive pressures on both the
tool manufacturers and end users have forced development and
deployment of optimal designs, with the important proviso that
the environment is high volume manufacturing with the
requirements of minimal down time (to sharpen tools, etc.),
immediate production with minimal set-up time [think SMED] and
repeatable/consistent results.
"Machine Shop Practice -- Vol I 2ed, Chapter 7 (Single Point
Cutting Tools and their Performance) pages 161-220" by Moltrecht
has a very detailed discussion of lathe type tooling.
Click on
http://www.industrialpress.com/en/Bo...3/Default.aspx
vol II
http://www.industrialpress.com/en/Bo...4/Default.aspx
(Get both volumes - you will use them.) Enco, Amazon and others
have these at discount.
Another useful reference source is the voluminous sales brochures
and web sites of the insert and tooling manufacturers.
Specialty tool and holder development/adaptation/extension for
non-commercial, low volume repair, model, prototype, and
home/hobby shop may be possible. One example is the tangential
type tool holders such as
http://www.bay-com.com/index.php?mai...b5a93620d80b8a
Note that this is a tangential tool *HOLDER*; the cutting action
is still radial. Horner [see below] shows a similar holder using
round tools. It should be possible by selecting the angle of
inclination to produce an 80-degree diamond using a square tool
bit, and even generate back/side rake as long as the top angle is
consistent. Of course the drawback is the use of HSS in a
cnc/carbide operation, but the tooling cost would be lower, and
with a proper jig/fixture quick to sharpen (just take a little
off the end at the proper [compound] angle)
Some of our posters that still operate screw machines (or have
good memories) may wish to comment on true tangential
tooling/tools such as skivers or roller back shave tools. Some
manufacturers are
http://www.championscrew.com/schiltter.htm
http://www.sommatool.com/
You might also take a look at the KRF Omnipost quick-change tool
system, which has a holder, designed to hold large carbide
inserts for use on smaller home/hobby lathes.
http://www.krfcompany.com/holderCarbide.html
http://www.krfcompany.com/
I doubt this is cost effective unless you luck into a cheap/free
supply of inserts, as most of the smaller lathes don't have the
power/speed/rigidity to fully utilize carbide, and most are
happier with high rake tooling.
Another area of information are (reprints of) the older machining
books as these have examples of tools and tooling that have
fallen from favor, but which you may adapt. Many of these are
from the depression era when labor was cheap and tools expensive
so are optimized to use inexpensive forms of tools [i.e.
rounds/rods] and to use up as much as possible of the tool.
One that comes to mind is "Practical Metal Turning p354-370" by
Horner.ISBN1-55918-277-6
A good source of these reprints is
http://lindsaybks.com/prod/allbks.html
Lindsay does not appear to have Horner in stock but you might try
http://www.abebooks.com/servlet/Sear...sts=t&y=5&x=50
Good luck and let us know what you discover/invent.
Unka' George [George McDuffee]
============
Merchants have no country.
The mere spot they stand on
does not constitute so strong an attachment
as that from which they draw their gains.
Thomas Jefferson (1743-1826),
U.S. president. Letter, 17 March 1814.