Maybe a dumb question about switching TPG inserts

[Overland]

I have a boring bar designed for TPG inserts.
The TPG inserts are of course flat top surface. Would it be possible to use TPMT inserts, of same size in this bar ?
I realize TPMT are designed for a center screw, but I'm thinking clamping with the TPG chipbreaker should hold the insert securely. I'm thinking light duty applications in low carbon steel. The advantage I can see is the improved geometry.
Bob

 

[atex57]

TPMR. Pick your chip breaker.

Ed.

 

[CarbideBob]

Yup will fit.
But that M means not ground on the sides.
This means maybe a side that has a bit of a flat area before the 10-11 degree rake.
It is only .003 to.010 wide but can be a problem child.
It is called the pressing land in the carbide world and has to be there when you pop the part out of the die.

Hole/no hole not a problem.
G in that third letter and no problems.
Bob

 

[Limy Sami]

Speaking as a certified Backyard Bodger (that's irony!) it's always worked for me.

 

[Overland]

Excellent, thanks guys !
I didn't realize TPMR existed
I like the "G".
Bob

 

[jims]

Yup will fit.
But that M means not ground on the sides.
This means maybe a side that has a bit of a flat area before the 10-11 degree rake.
It is only .003 to.010 wide but can be a problem child.
It is called the pressing land in the carbide world and has to be there when you pop the part out of the die.

Hole/no hole not a problem.
G in that third letter and no problems.
Bob

Do TPU versus TPG have that flat?

 

[CarbideBob]

Do TPU versus TPG have that flat?

Yup.
One tries to take as much of it as possible when grinding the top and bottom but it will still be there 95 percent of the time.

 

[jims]

Yup.
One tries to take as much of it as possible when grinding the top and bottom but it will still be there 95 percent of the time.

How much does this affect tool life and guality?

 

[Ox]

You guys still burning up TPG inserts?
Seriously?

UGH!

Man I have fought with those POS's for WAY too long before I gave up on them.
I still see a tool surface now and aggin, but it NEVER goes into a machine anymore!

Those inserts are always moving around....

I know they're cheap, but with all the broken tools and junked parts, an upgrade has a pretty quick ROI.

Ugh, I just had a shiver jist thinking about it...


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Think Snow Eh!
Ox

 

[Mtndew]

You guys still burning up TPG inserts?
Seriously?

One of the worst style of inserts ever made.

 

[atex57]

One of the worst style of inserts ever made.

Those things are wrong on several levels. Look at all the shell "mills" that were made for those inserts.

I told one newby that a lot of shops have one of those, very few have two of those.

Ed

 

[Terry Keeley]

These are great for boring:

ISCAR Cutting Tools - Metal Working Tools - ISO-Turning - Int. 60° Triangle 91° Approach - TPGT-SP

ISO-Turning - Int. 60° Triangle 91° Approach - TPGT-SP :

www.iscar.com

 

[eKretz]

I like 'em for finishing on the lathe. Good chip clearance. And I always found Kennametal TPMR with a good chipbreaker are great. TPG/U is not a good roughing insert, obviously...

 

[CarbideBob]

I run a 3 inch TPG-322 milling cutter in the B-port as go to. Made by the big K company long ago.
A 2 and 4 inch of my own design in the super wimpy 30 taper Chiron which does not like tool loads no matter what.
What most encounter is a 0 by 0 rake angle cutter . That does not work well and simply hammers like a madman.
Cheap and super easy to make. Cuts terrible but if you lay the insert back so it works much better you loose the 90 wall. (tradeoffs)
And then there is the insert clamp......some not rigid. Also it is darn triangle so pocking concerns and feed forces, twisting.

Nothing wrong with the base insert, it is the holder it sits in.
Many here are talking molded chipbreaker up top. That might change things going on a bit. (or a lot)

Would this and it's family be the second most common carbide insert made in the world? Why?
It is just a piece of carbide out there trying to do some work.
Bob

 

[Ox]

30 yrs ago maybe


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Think Snow Eh!
Ox

 

[CarbideBob]

30 yrs ago maybe


---------------

Think Snow Eh!
Ox

Snow,.
What is your oldest sled currently working in the barn? Was it poop or did it work?
Once or more went to something here on on a famous lake together. Throw down or shut up.
I so miss those days.
The days of must having the fastest sled in 300 miles are are now gone.
I am now OLD FART.
Back to maching, the kids know jack shit but will take over and pass us.
Bob

 

[Overland]

Long time ago I bought a Shars 2" dia TPG facemill for my BP clone.
That taught me about hammering, horrible thing.
Then got an Iscar 3" dia, 7 insert cutter with some angles to it; can't remember details as I sit here about to winterize my boat.
So much sweeter, in every way.
Bob

 

[eKretz]

Oh, and I forgot to mention, the ones I like for finishing on the lathe are the TPGF. Great chipbreaker geometry on those.