# Carbide Insert Questions



## RonWB1957 (Oct 6, 2016)

I have a coupe of different carbide inserts. One , ( phase II ), uses a TCMT 32.51 and the other ( Kennemetal ) uses a CNMG 32.51. They both came with inserts, but failed to mention what type of carbide or coatings. With all the different Carbides and coatings out there, my eyeballs are getting tired of sorting through all of them. None of which really tell you what would work best. All the abbreviations are driving me nuts. 
     So the question: I cut mainly brass, bronze ( 932 ) and stainless, ( 301, 304, and 416 ) on my lathe at this point. What type of carbide inserts or coatings should I be looking at? 
Question 2: Is there a definitive text out there I can read at my leisure, that can clarify the abbreviations, and characteristics. Not that I have that much free time. 
Thank you in advance. Ron


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## Doubleeboy (Oct 6, 2016)

CarbideDepot has lots of info online.


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## Metal (Oct 6, 2016)

Hey ron: i'm just starting with index able tooling myself.
The short answer is: whatever is cheapest, until you get used to the limitations of the tooling getting more expensive coated inserts is probably not the best idea 

uncoated tools are typically much sharper so I prefer them anyway!


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## 4GSR (Oct 6, 2016)

I've hoarded several hundred if not thousands of carbide inserts for all of the cutting tools I use.  If I can't figure out what grade it is, I start cutting with it. If the edge holds up I use it, it it doesn't hold up, I toss it and grab another.
You have two basic grades of carbide. One is C-2 and the other is C-6.  And from that you start branching out to all the others out there plus the endless coatings you can get on carbide.  

C-2 is mainly used for stainless steels, aluminum, nickel based alloys, and cast iron/ductile iron.
C-6 is mainly for Non-ferrous steels like 1018-1026, 1040-1045, 4130, 4140-4145, 6150, 52100 steels.

For C-2, numbers like N22, N25, 883, 570, K-68, KC-910, KC-950, KC-210, H-13, TP-15, TP-25, VC-29, VC-2, CQ-2.
For C-6, numbers like N55, N60, 370, 515, 570, 550,0350, K-21, K-420, KC-810, KC-850, KC-950, GC-1025, TP25, TP, 35,VN-8, V-05, VC-7.
These are older numbers that manufactures used to use.  This is just a tip of the iceberg.  

ISO has come in with their recommendations that use letters P, M, K, N, S, H to designate materials classes the inserts can be used for, too.  This has replace the old system of identification of inserts.  And when dealing with old and new inserts, you have to reference both systems for identifying inserts.  Ken


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## Wreck™Wreck (Oct 6, 2016)

If you have a manual machine and do not require 500 parts from one insert corner, a C5 tool will work well on steel, the various coatings are specific to the material to be turned and at what speed.

Above all understand that the vast majority of insert tooling is not designed for hobbyists but for production at the highest possible speed, feed and depth of cut under ideal conditions, these you will likely never achieve. You will actually find that if you buy a high end tool and can not use it at recommended speed and DOC it will likely fail rapidly or not produce the expected results.

As an example Sumitomo (I use their inserts daily) makes excellent inserts for steel, they recommend 500-750 SFM, at 600 SFM a 1/4" part would be turned at 9000 RPM's, will your lathe run this fast? http://sumicarbide.com/product/ac8025p-series-for-steel/

Paying a good deal of money for insert tooling that is intended for work well above what you can do with it is money not well spent.

The point being that obsessing over tooling that is not intended for what you are doing is simply a waste of money and time.

Choose wisely


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## mikey (Oct 6, 2016)

Wreck™Wreck said:


> If you have a manual machine and do not require 500 parts from one insert corner, a C5 tool will work well on steel, the various coatings are specific to the material to be turned and at what speed.
> 
> Above all understand that the vast majority of insert tooling is not designed for hobbyists but for production at the highest possible speed, feed and depth of cut under ideal conditions, these you will likely never achieve. You will actually find that if you buy a high end tool and can not use it at recommended speed and DOC it will likely fail rapidly or not produce the expected results.
> 
> ...



Well said, Wreck!


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## RonWB1957 (Oct 23, 2016)

Thank you.


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## BGHansen (Oct 23, 2016)

Here's an insert chart that may help.  Has the various sizes, shapes, etc., kind of a Rosetta Stone for inserts.  Doesn't have the ISO numbers (yet).  For example, a DCMT 21.51 is the same as a DCMT0702.

Bruce


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## jdedmon91 (Sep 16, 2018)

RonWB1957 said:


> I have a coupe of different carbide inserts. One , ( phase II ), uses a TCMT 32.51 and the other ( Kennemetal ) uses a CNMG 32.51. They both came with inserts, but failed to mention what type of carbide or coatings. With all the different Carbides and coatings out there, my eyeballs are getting tired of sorting through all of them. None of which really tell you what would work best. All the abbreviations are driving me nuts.
> So the question: I cut mainly brass, bronze ( 932 ) and stainless, ( 301, 304, and 416 ) on my lathe at this point. What type of carbide inserts or coatings should I be looking at?
> Question 2: Is there a definitive text out there I can read at my leisure, that can clarify the abbreviations, and characteristics. Not that I have that much free time.
> Thank you in advance. Ron



First of all most decent coated carbide will work at home shop feeds and speeds. Insert technology keeps evolving but the big things are coatings and chip breakers. I’m partial to the C style inserts because you can face and turn with the same tool. 

I used carbide for years @ the day job and since I was at a large manufacturing plant we made a lot of truck components. That means we had a lot of interest by insert vendors. The bottom line is the difference was slight in different brands or grades of the major companies. If you wish to learn more go to the major vendors and read their technical info. 

My advice is either use the popular CCMT style inserts and tool holders if you want a plug and play solution. I use this type mainly for boring because it works well in small diameter boring bars. My go to turning tool is a modified MCLNR tool that uses CNMG inserts. Mainly because I have a lot of them because of testing and gifts from vendors. Also eBay prices are better in the larger inserts than the CCMT type. I’ve posted several links to YouTube videos that shows me modifying tool holders. 

You will be ok just don’t let insert tooling overwhelm you


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## jdedmon91 (Sep 16, 2018)

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	class="bbCodeBlock bbCodeBlock--expandable bbCodeBlock--quote js-expandWatch">
	
		
WreckWreck said:



			If you have a manual machine and do not require 500 parts from one insert corner, a C5 tool will work well on steel, the various coatings are specific to the material to be turned and at what speed.

Above all understand that the vast majority of insert tooling is not designed for hobbyists but for production at the highest possible speed, feed and depth of cut under ideal conditions, these you will likely never achieve. You will actually find that if you buy a high end tool and can not use it at recommended speed and DOC it will likely fail rapidly or not produce the expected results.

As an example Sumitomo (I use their inserts daily) makes excellent inserts for steel, they recommend 500-750 SFM, at 600 SFM a 1/4" part would be turned at 9000 RPM's, will your lathe run this fast? http://sumicarbide.com/product/ac8025p-series-for-steel/

Paying a good deal of money for insert tooling that is intended for work well above what you can do with it is money not well spent.

The point being that obsessing over tooling that is not intended for what you are doing is simply a waste of money and time.

Choose wisely
		
Click to expand...


That is why I said that the grades of carbide in the home shop isn’t as critical. Heck Banggood carbide will work on most home lathes ok. I use their parting inserts and have good results 


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