Subject: Carbide toolholders

From: [email-masked] (Rich Klopp)
Date: 18 Sep 1996 23:23:47 GMT

I want to buy a carbide insert toolholder or two for my Jet 12" lathe. I'm
considering Acra (made by HB Rouse), USA and "Quality Import" copies, and
something similar made by US Borite. I'm thinking that the 3/8" shank size
ought to be about right; it uses 1/4" inside-circle triangular inserts.
These are listed in the MSC catalog and the Rutland Tool catalog.

I'll be using these for garage shop work on carbon steel & aluminum, not
for production work. I have a good Chinese knockoff Aloris toolpost that
makes for a reasonably rigid setup.

Can anyone recommend any one of these over the other? It looks like the
Borite uses somewhat different inserts. Are the inserts widely available?
They don't seem to list them according to industry standard codes. (Where
have I seen an explanation of those codes? They look something like
"TPMG".) I'd hate to buy something that you can't get inserts for 3 years
>from  now. Can I use these same inserts in somebody's boring bar?

Thanks in advance!

-- 
Rich Klopp

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From: [email-masked] (Scott Logan)
Date: 19 Sep 1996 12:59:49 GMT

In article <[email-masked]. 30.31> , From 
[email-masked] (Rich Klopp), the following was written:
> Can anyone recommend any one of these over the other? It looks like 
> the Borite uses somewhat different inserts. Are the inserts widely 
> available? They don't seem to list them according to industry standard
  > codes. (Where have I seen an explanation of those codes? They look 
> something like "TPMG".) I'd hate to buy something that you can't get 
> inserts for 3 years from now. Can I use these same inserts in 
> somebody's boring bar?> ?

Rich,

Try to stick with toolholders which use inserts that start with TPG TNG
or TNMG.  These are standard and VERY available inserts.  You should be
able to find a turning, facing, and boring tool which will all use the
same insert, and therefore greatly cut down your investment in inserts.

Also, don't skimp on the toolholders or inserts.  Try to get the best
quality you can possibly afford.  We generally use Kennametal brand here
in our shop, but that is admittedly like the Cadillac of toolholders and
inserts.  Some of the other brands which are excellent are Sandvik,
Carboloy, Valenite and Teledyne, in no particular order.

If you can get it to fit, you might also consider moving up to 1/2"
tooling.  This would be more available, and more rugged.  

--
 ----------------------------------------
 Scott Logan [email-masked]
 09/19/96 07:59
 http://www.loganact.com

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From: [email-masked] (Bruce Holder)
Date: 20 Sep 1996 03:28:04 GMT

Rich Klopp ([email-masked]) wrote:
> I want to buy a carbide insert toolholder or two for my Jet 12" lathe.

[snip]

> from now. Can I use these same inserts in somebody's boring bar?

  I can't address boring bars specifically, but I had similar questions
about inserts for turning tools. I was looking at a no brand import
line and a no brand USA line on the same catalog page with a prominent
statement that the inserts were not interchangeable. For some reason
lost in the mists of time, I ended up with both kinds off tool holders
and/or both kinds of inserts. YMMV, but in my shop the only detectable
difference was that the screw in one of them seated a little deeper
with the wrong kind of inserts and the screw in the other one seated a
little proud with the wrong kind of inserts.

  "Something like TPMG" is industry standard. It is the generic
terminology prescribed by the ANSI standard for carbide and other kinds
of ultra hard cutting tool inserts. The MSC catalog has many pages of
all kinds of inserts specified by this nomenclature, as well as charts
>from  several manufacturers showing, typically, subsets of the complete
terminology. Machinery's Handbook has a substantial section on carbide
inserts, including a complete description of the generic parts of the
standard, i.e. the parts that are not subject to vendor options.

  TPMG describes a triangular insert with 11 degree clearance angle on
the sides, fairly broad tolerance on the dimensions, and a countersunk
screw hole and chip breakers on both surfaces. An insert with a
non-zero clearance angle and chip breakers on both sides doesn't make
sense, but , for instance, TCMM and TCMT are the two inserts in the
turning tool story above. The trailing M and T denote differences in
the clamping holes, which correspond exactly to the difference I saw
in screw seating depth.

  A quick scan through the MSC catalog showed boring bars that take
TNG, TNU, TPG, TPU, TNMA, TNMG, TDAB, TPGB, TPGH, TPGC, TPMT, TPEE and
TBEE inserts. You may have to do some research to get behind the
vendors' numbering systems, but as far as I can tell, essentially all
of the commercially available carbide inserts fit into this structure
and can be cross referenced. All the vendors would love to get you
locked into their system, but they would also love to take your
business away from whoever you're buying from now, so they typically
provide cross references to make it easy for you to find replacements
for somebody else's inserts.

  As you noted about the Borite boring bars, the Borite lathe tool
holders took a different size insert that may not have a substitute.
That's one reason I didn't buy Borite, along with the fact that they
charge correspondingly more for the inserts and significantly more for
the tool holders. On the other hand, if I had bought Borite, I wouldn't
worry very much about about them going out of business and leaving me
stranded without a supply of inserts.

Bruce

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From: [email-masked] (J. Kimberlin)
Date: 20 Sep 1996 18:08:22 -0700

In article <[email-masked]>,
>ought to be about right; it uses 1/4" inside-circle triangular inserts.

I have a 13" x 36 Jet belt drive with an Armstrong toolpost.  I use the 
1/2" Rouse tool holder using TNMG inserts.  These cost about $1.00 each 
but are 3/8" IC.  The 3/8" shank size is a little small for ridgidity I 
would think.  I try to get all my tool holders to use the TNMG insert.

>from now. Can I use these same inserts in somebody's boring bar?

The industry codes are usually found in about any catalogue somewhere.  
They are probably in the FAQ.  I can't recommend Rouse over any of the 
other brands sold by MSC, Travers, Rutland, and others.  Mostly they are 
all the same.  If you have a good vertical mill you can make your own.

>Thanks in advance!

JerryK