# Proper Inserts



## BROCKWOOD (Oct 15, 2019)

I'm running low on these from Grizzly & would like to upgrade to something that has better performance. Any recommendations?


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## NCjeeper (Oct 15, 2019)

My everyday inserts are CNMG 432's. I sometimes will use a 431 if a need a sharper nose radius.


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## Bob Korves (Oct 15, 2019)

NCjeeper said:


> My everyday inserts are CNMG 432's. I sometimes will use a 431 if a need a sharper nose radius.


Which is a completely different style and size than Brockwood was asking for, but it is a triangle...


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## Janderso (Oct 15, 2019)

The TCMT inserts you received from Grizzly are probably of lower quality.
There are plenty of sources that would gladly take your order.
McMaster Carr
Carbide Depot
Travers usually has a value line and a professional line.
And the list goes on.
Is that what you are asking?


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## ezduzit (Oct 15, 2019)

Try MSC for your inserts. Inserts vary depending on what material you're cutting.


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## matthewsx (Oct 15, 2019)

I got these from aliexpress










https://www.aliexpress.com/item/4000063154952.html?spm=a2g0s.9042311.0.0.b2864c4dxMZ3Hw

Was surprised when they showed up and were Mitsubishi made in Japan. Took about a month but the price was right.


John


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## mattthemuppet2 (Oct 15, 2019)

TCGT inserts will get you a sharper and freer cutting edge, at the expense of longevity in steel. Would also be worth getting some turning holders too and keep the boring bar for boring.


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## macardoso (Oct 15, 2019)

I like Shars for my inserts. I usually buy their TIN inserts for steel and their high polished inserts for inserts. 






						shars.com - Indexable Inserts
					

Shop Shars Tool today and see why customers choose our high quality indexable inserts at a great value, same-day shipping and devoted customer support




					www.shars.com


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## matthewsx (Oct 15, 2019)

macardoso said:


> I like Shars for my inserts. I usually buy their TIN inserts for steel and their high polished inserts for inserts.
> 
> 
> 
> ...



You cut inserts with your inserts?


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## macardoso (Oct 15, 2019)

matthewsx said:


> You cut inserts with your inserts?



Meant aluminum! polished inserts for aluminum!


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## Cadillac STS (Oct 16, 2019)

Is there a resource that helps identify what insert you have and gives the cross reference to what insert would work?

For example:  I have a triangle insert and there are no markings.  What type is it?  What is the number for it and what can I replace it with?

*Like for a light bulb or battery a chart of which other insert would help buy what is needed.  Cross reference to other manufacturers numbers for inserts.  *

And which one would cut what surface better.

I know it is out there...  Would someone post a link here.


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## matthewsx (Oct 16, 2019)

Here's one:






						MITSUBISHI MATERIALS CORPORATION
					

This homepage offers Mitsubishi Materials cutting tools information.



					www.mitsubishicarbide.com


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## macardoso (Oct 16, 2019)

Cadillac STS said:


> Is there a resource that helps identify what insert you have and gives the cross reference to what insert would work?



This is a little more complicated of a question than you may realize. There are thousands of insert geometries out in the world and many of them only work with one manufacturer's specific tool.

There are a handful of extremely common inserts which you are likely to stick with. These are often available from top manufacturers in the $10-20 per insert range and all the way down to import ones at less than $1 a pop.

Here is a decent webpage to start the discussion:






						MITSUBISHI MATERIALS CORPORATION
					

This homepage offers Mitsubishi Materials cutting tools information.



					www.mitsubishicarbide.com
				




The easy one is the shape. This is the first letter in your insert "TCMT 32.51". T matches up with "triangular". The 60 degree corner angle is good for light machining and finishing but isn't the strongest insert. The larger the corner angle (up to 135 degrees for an octagonal insert) the larger the imparted cutting forces on your machine, but the more robust the insert - these may be good for roughing. The thin "V" inserts (35 degree) can take extremely light and precise finishing cuts with little forces, but will quickly chip if you cut too hard with them.

The second letter is the relief angle. This determines if the tool is positive or negative rake (although negative rake tools with chipbreakers can act like positive rake tools). A positive rake tool like the TCMT 32.51 in the example above will cut with lower cutting forces and horsepower than a neutral or negative rake tool, but it is single sided and less strong. A neutral insert like CNMG432 will be able to flipped over to double the number of cutting edges. Neither my G0704 or my 12x36 lathe have enough rigidity or power to really make good use of negative rake tools with neutral inserts.

The next letter is the tolerance. I don't pay attention to this since I am always re-zeroing my tools, but if you run highly automated production, it might be worth it to you to pay more for an insert which can be replaced and have the tip end up in the exact same location.

The final letter is the clamping system and whether or not it has a chipbreaker. This is selected to match the holder you are using.

The next numbers 32.5 (in the example TCMT 32.51) give the insert size. They are the size in mm of the largest circle that can be inscribed inside the boundary of the insert when looking from the top. Shown as I.C. in the image below.




Some manufacturers will add an extra code here (TCMT32.5^1) to denote the insert thickness, but it is often dropped in lower cost insert designations.

Finally the last number is the insert corner radius. To me, this is the most important number since it determines how the tool cuts. Large radii force you to take large depths of cut, but are strong and want to remove lots of material. Small radii allow you to take whisker thin finishing cuts, but are not strong enough to handle heavy material removal.

Two more somewhat import things to cover are insert grade and coating. The grade is the designation for the actual carbide material. Each manufacturer will have then own, but some are suited to high temperatures, some to highly abrasive materials, some to very hard materials, etc. On top of that, the coating will offer additional protection from heat and wear. Use a coating (even just TIN) on steel, and try to avoid using coatings on aluminum (unless it is specifically made for aluminum).

My commonly used inserts in my home shop are:

TCMT21.50 (small fine finishing)
TCMT32.51 (light boring on lathe)
CCMT32.50 (Finishing in steel)
CCMT32.51 (Roughing in steel)
CCGX32.50 (Finishing in aluminum)
CCGX32.52 (Roughing in aluminum)
16ER           (External threading)
16IR            (Internal threading)
11IR            (Internal threading for small holes)

There is a lot more to indexable tools, but this is a starting place. I strongly suggest buying indexable tools with the required insert and hardware marked on the tool. Shars does this with all of their tools as well as most big name manufacturers.


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## mattthemuppet2 (Oct 16, 2019)

macardoso said:


> The next letter is the tolerance. I don't pay attention to this since I am always re-zeroing my tools, but if you run highly automated production, it might be worth it to you to pay more for an insert which can be replaced and have the tip end up in the exact same location.



that letter also signifies ground vs. molded. eg. TCMT is a molded insert, good for steel, cast etc with a sufficient depth of cut. TCGT is a ground insert, good for aluminium or light cuts in steel. It can also take off very shallow cuts of 0.001" or even less sometimes.


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## Mitch Alsup (Oct 16, 2019)

BROCKWOOD said:


> I'm running low on these from Grizzly & would like to upgrade to something that has better performance. Any recommendations?



I got most of my inserts (along with the insert holding tools) through AliExpress.


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## BROCKWOOD (Oct 17, 2019)

Cadillac STS asked the right question, which got Matthewsx to share the chart & Macardoso to explain the chart!!!

I tried to get the chart to all fit on 1 page - but it still won't be readable in a 8 1/2 x 11 print.




Time to digest & cross reference all this so that I can ask better questions. Thanks Guys!!!


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## MrWhoopee (Oct 21, 2019)

Mitch Alsup said:


> I got most of my inserts (along with the insert holding tools) through AliExpress.



Same for me. I have bought a full assortment of boring, turning and threading tools (internal and external) and have yet to be disappointed.


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## BROCKWOOD (Oct 21, 2019)

So, Matthewsx bought from Aliexpress inserts made by Mitsubishi (the creator of the chart above) & the 2nd half of the part number or type doesn't match their own published info? At least I'm learning a few things!

1. Mine is a weak import lathe, so that even with a 10" 4 jaw chuck there will not be any hogging out steel. 
2. I was using an insert that likes to take very fine cuts regardless of material being cut.
3. Interrupted cuts on hardened steel in the 3.5 - 4 inch range is at the limits of my lathe's abilities. 

But, I did reach my target reduction & the part is done even without running out of inserts! Several noticed my use of a boring bar for outside turning. I have a few of the correct square insert holders that I began cutting on this project with, but was just experimenting. This boring type tool holder gave a better cutting angle that allowed me to put off the problem I was having. See, the top nut on my Shars sold QCTP got stuck & I could no longer change the angle on it.

Now that the part is complete, the tool post is apart & upgrades will be covered in another thread!

Thank you all for helping!


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## MrWhoopee (Oct 21, 2019)

I suspect the Mitsubishi branded inserts from Aliexpress were counterfeit. There's a lot of that going around.


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## Jimsehr (Oct 21, 2019)

MrWhoopee said:


> I suspect the Mitsubishi branded inserts from Aliexpress were counterfeit. There's a lot of that going around.


I think inserts are better suited for production. Most home shops only make one piece at a time. That said cnmg inserts give you 4 sharp edges. So it might be worth trying . And if you buy another tool you can also use the other 4 cutting edges for facing After you have dulled the first 4 edges.
Me , I‘m so cheap I often sharpen dull inserts.
Jim


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## MrWhoopee (Oct 21, 2019)

Jimsehr said:


> I think inserts are better suited for production. Most home shops only make one piece at a time. That said cnmg inserts give you 4 sharp edges. So it might be worth trying . And if you buy another tool you can also use the other 4 cutting edges for facing After you have dulled the first 4 edges.
> Me , I‘m so cheap I often sharpen dull inserts.
> Jim



I'm as cheap as they come, just ask my wife. If I were paying $10-$20 per insert, I would agree that they are not justified in a home shop. Priced at somewhere around $1 per, it's just too easy to just drop in a fresh edge. The inserts the OP was using are 78 cents each with free shipping.








						US $7.75 59% OFF|CCGT09T304 AK H01 CCGT 09T304 Aluminum cutter blade Insert Cutting Tool turning tool CNC Tools AL +TIN Alloy wood Tungsten|turning tool|cutting toolcnc turning tools - AliExpress
					

Smarter Shopping, Better Living!  Aliexpress.com




					www.aliexpress.com


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## Jimsehr (Oct 21, 2019)

MrWhoopee said:


> I'm as cheap as they come, just ask my wife. If I were paying $10-$20 per insert, I would agree that they are not justified in a home shop. Priced at somewhere around $1 per, it's just too easy to just drop in a fresh edge. The inserts the OP asked about are 78 cents each with free shipping.
> 
> 
> 
> ...


I would sure try inserts at 78 cents each . But the post said he was getting them from Grizzly. And they want $8.95 ea for g6706 tcmi 21.51 inserts.


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## matthewsx (Oct 21, 2019)

MrWhoopee said:


> I suspect the Mitsubishi branded inserts from Aliexpress were counterfeit. There's a lot of that going around.



They might be but I fail to understand why someone would go to the trouble of counterfeiting them and not sell them as such. I didn’t order Mitsubishi or Korloy so I’ll try them and see how they work out.


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## MrWhoopee (Oct 21, 2019)

Jimsehr said:


> I would sure try inserts at 78 cents each . But the post said he was getting them from Grizzly. And they want $8.95 ea for g6706 tcmi 21.51 inserts.



Yeah, I'm not sure how I got pulled off to the CCMT inserts, the TCMT 21.51 inserts seem to range from 27 cents to $1.50 depending on grade and coating.









						13.0US $ |TCMT110204 TM HP1025 Metal Internal Turning Tool  Carbide Inserts Cutter CNC Lathe Turning Tools|Turning Tool|   - AliExpress
					

Smarter Shopping, Better Living!  Aliexpress.com




					www.aliexpress.com


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## mksj (Oct 22, 2019)

There are a few US based eBay sellers that seem to sell surplus non-counterfeit inserts, I also purchase some from European sellers. Often hard to detect the difference of OEM vs. counterfeit but  often it can be detected by the the labeling and enclosure differences if you know what you are looking for. The Mitsubishi, Sandvik and Korloy seem to be in abundance from Chinese sellers, not saying they are all counterfeit as some state that they aren't. I have purchased from a few of these sellers who guarantee OEM and performance wise they seem to hold up well. There is (and will continue) to be quite a debate as to using inserts vs. HSS on smaller lathes, they each have their merits. But smaller less rigid machines do better with HSS. A lot also depends on the tool holder, geometry, and type of insert. A positive or neutral rake insert pocket can produce some very nice cutting performance with reduce Hp requirements.

I would not recommend a negative rake insert geometry for smaller lathes, with a few exceptions. I would avoid unbranded or generic brands like Cobra, Rishet, NWP, tried some Cobra inserts years ago and they would break very quickly. So you are not saving any money in the long run if the insert is not durable and the cutting performance is poor.

I usually recommend finding insert brands/configurations/coating that work for you and then sticking with those. Inserts, in particular many of the older traditional styles, can be picked up for  around $2 a piece. Example below would be for general turning in ferrous materials, the Mit's VP15TF coating holds up very well. Seco, Kennametal are  more expensive, but seem to be rarely counterfeited.








						10 pcs MITSUBISHI Carbide inserts TCMT 21.51 / TCMT 110204 Grade VP15TF  | eBay
					

Find many great new & used options and get the best deals for 10 pcs MITSUBISHI Carbide inserts TCMT 21.51 / TCMT 110204 Grade VP15TF at the best online prices at eBay! Free shipping for many products!



					www.ebay.com
				



Seco, more expensive, TP2500 coating is a durable general machining coating for ferrous metals.








						TCMT 21.51 MF2 110204 TP2500 SECO ** 10 INSERTS *** FACTORY PACK ***  | eBay
					

Find many great new & used options and get the best deals for TCMT 21.51 MF2 110204 TP2500 SECO ** 10 INSERTS *** FACTORY PACK *** at the best online prices at eBay! Free shipping for many products!



					www.ebay.com
				




TCGT (ground edge as opposed to molded) would be used for softer materials like aluminum. I have purchased inserts from this Chinese seller and the same to be authentic.








						KORLOY TCGT110204-AK H01 TCGT21.51-AK Carbide Insert 10PCS/Box for sale online | eBay
					

Find many great new & used options and get the best deals for KORLOY TCGT110204-AK H01 TCGT21.51-AK Carbide Insert 10PCS/Box at the best online prices at eBay! Free shipping for many products!



					www.ebay.com
				




Some US seller's like Shar's seem to be trying to carry a bit better quality on some items, so also may be worth a try. Inserts for me can last 2-3 months, so a cheap investment even if they cost a bit more for a quality insert. I tend to also standardize on inserts for different holders, for ferrous materials I mostly use CCMT inserts, and also use the same insert for my boring bars.


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