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TNMG Iron Root

I bought a couple straight holders and some TNMG 1604 (Iron Root) inserts a while back. Shipped from China. I bought a bunch of bright and some coated ones. So far I have just used one point on one bright insert. Its turned some stainless 304 pens before Christmas. A few days ago I used it to turn down the hard HSS shank on a carbide chucking reamer. Today I was turn a roughly 2 x 2 square aluminum assembly with stainless pins and screws through it down to a 1 inch round. Not much feed, but a lot of depth of cut. I had it going THUNK THUNK THUNK pretty darned hard to get the corners off, and when I got into the pins I was still taking off a lot. I'm going to have to finish to final dimension with the insert, because I no amount of polishing could match the finish I am seeing. I've put aluminum on the buffing wheel that doesn't look that shiny.

So, I guess my question is this. Can I run this same insert in a right hand, left hand, and boring holder and expect similar results? Obviously insert tools set up for them at the proper angle. Not just any old insert tool.

Just one point so far, and there are six of them on each insert. Holy crap! I bought two boxes of them because they were cheap and I figured I'd go through them pretty quick.

Haven't even tried the coated ones yet. In fact I forgot I had them until I dug in the lathe tool cart to look up what these inserts are. DANG!

Reply to
Bob La Londe
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Since no one else has replied............... I think you can use the same insert on both right and left holders. And in a boring bar, but would not expect the boring bar to be as stiff. Carbide comes in different grades. Some are harder, some less likely to chip. So what you have may not be th e best for a job, but I think it can be used.

Now for something completely diffecent. Can anyone explain why they use th e shape they use. I have a couple of holders that use triangle inserts. W hy would I want a different shape? Why is as 86 degree so popular? Why is a Square not as popular? Where is there information on choosing an insert shape. CarbideDepot.com has a pretty good chart on insert designations, but not on choosing an insert shape.

Dan

Reply to
dcaster

On Thursday, July 5, 2018 at 8:37:20 AM UTC-4, Gunner Asch wrote: .

Thanks. That is a great selection of information on inserts. It will take me some time to absorb all of what you posted.

Dan

************* The first video "Inserts for Noobs by a Noob" was ok, but it didn't really do anything for insert selection. I already knew most of the letter designations, and I have a copy of the Engineer's Black Book next to the keyboard on my desk with a nice lookup table for the rest. Found a table of usage (choosing an insert) for the various shapes on the Carbide Depot site. That was really useful. Interestingly a triangle (T) had more boxes checked in usage than any other shape. Roughing was not listed as high as others, but it was checked. Hard materials was not checked, but maybe a zero rake angle (N) makes the triangle insert I was using just strong enough since I have used it for 4140QT (medium hard) and HSS (harder) with good results. I may print a copy of that table and add it to my "Pink Book." The Pink Book is a 3 ring binder my daughter gave me that I keep copies of useful tables in on the shop floor. It provides faster reference than the Machinery's Handbook (my copy is circa WWII) or even my more current Engineer's Black Book.

I have not yet gone through all the provided material, but there is atleast one jewel in the mix already. Its enough to tell me I may want to pick up atleast a right hand and left hand TNMG insert holder in the same size as my straight holder, and take a couple other less often used tools out of my tool holders.

Reply to
Bob La Londe

This one?

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Reply to
Jim Wilkins

This one?

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Yep, that's the one.

Reply to
Bob La Londe

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