Are there advantages to using "too big" holders milled down to size?

I understand that some have machined holders so they can use them in
their specific tool posts, but if I were to mill, for instance, a BXA
holder into AXA holder would there be any advantages over an original
AXA holder?

I assume that any change in strength and rigidity would be
insignificant, but would there be a benefit as far as the option of
using better or more easily gotten inserts?

Experiences would be appreciated.

Thanks a lot.

Darren Harris
Staten Island, New York.

wrote in message
oups.com...
Are there advantages to using "too big" holders milled down to size?

I understand that some have machined holders so they can use them in
their specific tool posts, but if I were to mill, for instance, a BXA
holder into AXA holder would there be any advantages over an original
AXA holder?

I assume that any change in strength and rigidity would be
insignificant, but would there be a benefit as far as the option of
using better or more easily gotten inserts?

Experiences would be appreciated.

Thanks a lot.

Darren Harris
Staten Island, New York.


I'm of the opinion that unless you gain the use of an insert holder that
otherwise may not have been available to you, there is no good reason to
mill them down. Size of insert goes up with larger holders, so the
potential cost is greater, but there's often no benefit in using larger
inserts. The exception can be where one has a center distance that
precludes using a reasonable sized holder, so milling makes it possible.
My Graziano lathe, equipped with an OK Rubber Welders square indexing tool
holder (by choice---I like that particular design) is an example. The
largest tool that the machine will accommodate with that setup is only 1/2".
Many of the 1/2" holders use a tiny insert, which are ill suited to the
horsepower I have at my disposal (3 horse), so I have milled down a 5/8"
holder for running negative rake TNMG-322 inserts. They're very popular and
available reasonably priced. I gained something in the process. You may
or may not, but if you have something going that makes it attractive,
there's certainly no harm in doing so. Depending on the nature of the
inserts in question, you may find that larger inserts may not offer the
small tip radius that you desire. All depends on the inserts. Do your
homework before investing.

Harold

I ran a company years ago that had German made peg board machines for
production work. [pre CNC]
They were automatic turret lathes , that we ran 3 shifts a day and they had
metric tool holders.
We took heavy roughing cuts and broke lots of insert tools in the process.
We were using Kennametal
tooling and I changed from using 1 inch insert tools to some huge Kennametal
insert tools .I think they
were about 2 1/2 shank size . Any way I milled the bottom of these huge
tools to center line and drilled
and bolted to them table to replace the tool holders that came with the
machines. Making them tool posts
with built in inserts. Our tooling cost and breakage went way down . I think
it was because they were so rigid.
Jim


"Harold and Susan Vordos" wrote in message
...

wrote in message
oups.com...
Are there advantages to using "too big" holders milled down to size?

I understand that some have machined holders so they can use them in
their specific tool posts, but if I were to mill, for instance, a BXA
holder into AXA holder would there be any advantages over an original
AXA holder?

I assume that any change in strength and rigidity would be
insignificant, but would there be a benefit as far as the option of
using better or more easily gotten inserts?

Experiences would be appreciated.

Thanks a lot.

Darren Harris
Staten Island, New York.


I'm of the opinion that unless you gain the use of an insert holder that
otherwise may not have been available to you, there is no good reason to
mill them down. Size of insert goes up with larger holders, so the
potential cost is greater, but there's often no benefit in using larger
inserts. The exception can be where one has a center distance that
precludes using a reasonable sized holder, so milling makes it possible.
My Graziano lathe, equipped with an OK Rubber Welders square indexing tool
holder (by choice---I like that particular design) is an example. The
largest tool that the machine will accommodate with that setup is only
1/2".
Many of the 1/2" holders use a tiny insert, which are ill suited to the
horsepower I have at my disposal (3 horse), so I have milled down a 5/8"
holder for running negative rake TNMG-322 inserts. They're very popular
and
available reasonably priced. I gained something in the process. You may
or may not, but if you have something going that makes it attractive,
there's certainly no harm in doing so. Depending on the nature of the
inserts in question, you may find that larger inserts may not offer the
small tip radius that you desire. All depends on the inserts. Do your
homework before investing.

Harold

" Jim Sehr" wrote in message
...
I ran a company years ago that had German made peg board machines for
production work. [pre CNC]
They were automatic turret lathes , that we ran 3 shifts a day and they
had
metric tool holders.
We took heavy roughing cuts and broke lots of insert tools in the
process.
We were using Kennametal
tooling and I changed from using 1 inch insert tools to some huge
Kennametal
insert tools .I think they
were about 2 1/2 shank size . Any way I milled the bottom of these huge
tools to center line and drilled
and bolted to them table to replace the tool holders that came with the
machines. Making them tool posts
with built in inserts. Our tooling cost and breakage went way down . I
think
it was because they were so rigid.
Jim

Jim,

An excellent example of benefiting from the upgrade, to which I had
alluded. There are times when small inserts just don't cut it (no pun
intended) and modifying larger insert holders so avoid breakage is the order
of the day.

Yours is a very impressive story.

Harold