HELP: Inserts for MTFNR-103 Lathe Tool Holder

MyLilMule

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Carbide inserts and the designations continue to confuse me. There are so many variations that I still get a little flustered trying to figure it out.

I got this tool holder when I bought a lathe at auction. I figure why not put it to use as a dedicated facing tool.

I googled the tool holder number and came up with a link to this page. The graphic seems to match this holder. The other numbers, I believe, represent the part numbers for the shim, post, clamp and screw.

That page described the insert as being TN__33. I assume a TNMG 332 would probably work.

T - Triangle shape
N - 0 degree clearance (the holder has built in rake angle)
M - Tolerance +/- .002 to .006 (not relevant to the size, I know)
G - Double sided, hole in the middle

3 - 3/8" inscribed circle
3 - 3/16" thickness
2 - 1/32" corner radius (irrelevant, I know this could be almost anything I need it to be, but 1/32" seems fair for starters)

When I measure the insert that's already there, everything seems to match that, except the thickness. Instead of 3/16" (the second 3 in 332) the insert in the holder I have is more like 1/8", which would be a 2. So TNMG 322 maybe? Is it possible the insert I have in there is "wrong" or at least "not right enough"?? Or is it OK to use an insert that is thinner than the one perhaps called for?

In the immortal words of Princess Leia Organa, "Help me Obi-wan Kenobi. You're our only hope."

Thanks in advance!

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My Dorian catalog lists the insert for that size holder to be a 322. The ITSN-333 on the side of the holder is the seat number in case you need to replace that in the future. You need to go up to a 1” shank size for the 332 insert size to be correct.

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You’re welcome! You might want to download the Dorian tool catalog from their website, it is laid out really well and it looks like their tools use the industry numbers for the most part. Their threading catalog is really good too, I use it a lot when I am searching for what part numbers to search ebay when I need something new.
 
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