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Replacing inserts

jucasan

Plastic
Joined
Mar 18, 2017
Looking to get new inserts and don't really know exactly what to get. The holder has a NCLNR-083A NE7 engraved.

Looked on MCMaster and found MCLN code. Then the option is CNGG or CNMG and I don't know the difference. Can anybody tell me what to pick. Maybe a link that explain what all this nomenclature means.

Thanks
 
XXGX/XXMG are the same insert the only difference being the tolerance to which it's made. M will be a moulded and sintered insert and a G insert will be a moulded, sintered and ground insert which will be more dimensionally accurate. If you are making one piece it doesn't really matter however changing inserts during a production run can directly affect a part feature and may require walking the dimension in again.

Edit: I was just heading to grab the carbide depot link and Rob beat me to it.
 
XXGX/XXMG are the same insert the only difference being the tolerance to which it's made. M will be a moulded and sintered insert and a G insert will be....... ground

For my own interest.. Maybe carbide Bob, or an Ex-KENNAmetal salesman would know.

That third letter, as far as I know only denotes the tolerance. BUT it seems, as you've said,
M for molded, G for ground.. That's how I remember it. I know there are some other letters in there also.

T for Triangle.
D for Diamond
V for Very Sharp Diamond
R for Round
S for Square
C for Corta a squished square... Cinda a diamond, but not really?


How did it all start? And what did it all mean at the beginning??
 
I have just always ass-u-me'd that the only way to hold the tolerance was to grind it so G might as well stand for ground? Either way like you said, it's a nifty little mnemonic device to remember the difference.

You left out W for a lumpy... triangle? Also called a trigon insert.
 
Last edited:
Log this under....I don't want to know.:)

Yup trigon, a much latter addition.

Original spec drawn up by the Cemented Carbide Producers Association and submitted to ANSI. (Carboloy, Firth, Kennametal and a few others)
Easy at first as there where Squares, Diamonds, Rounds, Triangles .
(interesting on Corta, thinking more grab a letter below the D)
Eight letters/numbers:
Shape, clearance angle, class, type, size, thickness, cutting point, other.
Then manufacturers started adding new stuff. Some became part of standard, others industry standards, and some just bastard.
The eight position or tail of the size number being other became a wild card for any insert maker.

In the third is also U which is utility, R which is rough molded with grind stock all over and S which is grind stock top and bottom with IC pressed to sized.
SNR-430 makes perfect sense to me and on many of my POs, not so much sense to end users as it becomes something else once processed.
Tolerance of the class in M and U depend on ic size.

Simple once it is all very confusing now and while I can look at most and tell you the basic I often have to go searching more information.

Much has been added on since the late 50s and the letters sometimes are just free letters to use.
The tail end of the number can be anything from milling cutter flats to nose wipers, edge preps or special chipbreaker geometry.

A G or P in the fourth maybe radically different or maybe spelled out in number 8 as you may make 5 G's and a few P's.
It's all so confusing.....Life was easier in the day of SPG-322A.

I "get" about 80% of insert callouts, can look at most and know the letters and numbers, have to go searching many times.
Know any two chipbreakers from different companies with the same letters are not the same but I've only been exposed to this madness for a while.

Part of the deal is you want a patent on your insert. The Pez dispenser is free with some candy, but only our candy will fit.
The big K hit me on this one to the tune of $90,000 lawsuit on top-notch a ways back so gun shy here with propriety designs.

Still wondering about the OP "N" holder and if it is a "M". A picture would be nice.
Bob
 
Part of the deal is you want a patent on your insert. The Pez dispenser is free with some candy, but only our candy will fit.
The big K hit me on this one to the tune of $90,000 lawsuit on top-notch a ways back so gun shy here with propriety designs.

Still wondering about the OP "N" holder and if it is a "M". A picture would be nice.
Bob

OUCH!

So does this impair rebuilding at all, or is that just repair work and therefor ok.

Gotta love the way the world works. I mean, I get it, but holy crap.
 
OUCH!

So does this impair rebuilding at all, or is that just repair work and therefor ok.

Gotta love the way the world works. I mean, I get it, but holy crap.

Repair or rework is fine. No legal problems.
Same with regrinding of used inserts.
You will also get away with small scale copying of designs and flying "under the radar".
Only once you become a pain in the pocketbook or a risk of it spreading wide will they come after you.

Understand that I am still friends with those who came after me and won here. I walked the line and got spanked.
Throughout the legal process we talked often to each other very informally.
I lost, have no qualms or complaints and for sure think they are a stand up company.
I also won a similar sized suit against a Japaneses tool company for screwing my contract so yes the world works strangely.
One gets big wins and big loses. Hopefully you come out even.
Bob
 








 
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