# Replacement TP 22 Carbide insert?



## StrikerDown (Feb 16, 2009)

I have some older indexable tool holders that use a TP 22 Carbide insert. 

I need to find some replacement inserts.

All I can figure out is that T= triangle, P= 11 deg relief after that I'm lost.

I'm down to my last insert so it's time to find replacement inserts preferably or new holders and inserts.

Also eBay has an end mill with R8 shank that uses TP 22 inserts... that could be handy to have with interchangeable inserts.


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## precisionworks (Feb 16, 2009)

I believe that TP22 refers to the coating type, but not the insert shape or the IC size. Here's a Seco insert that's TP22 in a square shape:

http://cgi.ebay.com/SCMT-070308-F2-TP22-SECO-INSERT_W0QQitemZ350117596363QQcmdZViewItem

Any chance you have the box in which the inserts came? If not, an accurate drawing would help narrow down what you have.


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## StrikerDown (Feb 16, 2009)

You are probably correct but here is why I was thinking this was the insert ID.

1. The tool holder is stamped "Insert - TP 22"

2. the End mill on eBay Says it uses Insert TP 22. See the link:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=180323053318&ssPageName=MERC_VI_RCRX_Pr4_PcY_BIN_Stores_IT&refitem=180319381474&itemcount=4&refwidgetloc=active_view_item&usedrule1=CrossSell_LogicX&refwidgettype=cross_promot_widget&_trksid=p284.m184&_trkparms=algo%3DCRX%26its%3DS%252BI%252BSS%26itu%3DISS%252BUCI%252BSI%26otn%3D4

It is hard the see the insert on the end mill but that is what they look like and judging by the size of the R8 shank it's also about the right size. 

I found an insert retailer on the web that lists all the sizes and specs for their inserts so I will measure my remaining insert and try to locate a generic replacement.

It could be that since these are so old the inserts were identified differently back then. They were not new when I got them over 25-30 years ago!


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## Anglepoise (Feb 16, 2009)

I suspect its a TPG 220. ( or 221,222 )
This is a triangle insert, no hole, 11° and was the old description system used years ago. I can't remember exactly but I think 220 has to do with nose radius,thickness and inscribed circle dimension.

If yours are triangle and no hole, try and do a search for the cross reference to the above.


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## precisionworks (Feb 16, 2009)

Another way to narrow it down is to measure the IC (inscribed circle).

IC is a circle that fits exactly within the boundaries of another shape.







The easiest way (at least for me) to find the IC, is to lay a circle template over the insert.







The hard part is that there isn't much difference in sizes between a 220, 320 and 420:thumbsdow


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## larry117 (Feb 16, 2009)

This link should help you out:
http://www.pgstools.com/servlet/the-template/carbideinsertidentification/Page#Cutting

Imagine that your toolholder reads TP_ 22_ The first blank is probably gonna be a G. The second blank is the nose radius of the insert, the larger the number the larger the radius, so you decide what you want for this. 

I buy a lot of cheap TPG inserts off ebay for rough milling and they work great. 

If its a more specific insert you need try MSC or somewhere like that. 
http://www1.mscdirect.com/CGI/N2DRVSH?PACACHE=000000085041378


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## StrikerDown (Feb 16, 2009)

How do you spell BINGO!

TPG 220	TPG110301 1/4 1/8 0	
TPG 221	TPG110304 1/4 1/8 1/64	
TPG 222	TPG110308 1/4 1/8 1/32

Measurement from my insert:
IC=.25
T= .130
NR= Idunno!

I don't want a 0 nose radius (sharp) But I'm not sure which of the other two would be the best for turning steel, SS and/or Aluminum?

Seems like the larger radius would be more durable and possibly render a smoother finish.

Thanks for the help, you guys are the best! :wave:

Ray


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## gadget_lover (Feb 16, 2009)

I use them this way;

220 for threading
221 for harder materials, inside corners, etc.
222 for a nice smooth finish, especially on 6061.


Dan


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## StrikerDown (Feb 16, 2009)

Hmmm, I guess I can use 0 nose after all, had not thought about using it for threading.

Thanks Dan


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## precisionworks (Feb 16, 2009)

> Seems like the larger radius would be more durable


The larger radius is a good, general purpose choice. My 'normal' insert is a CNMG XX2, and they can leave a glassy smooth finish with the right inputs.



> best for turning steel, SS and/or Aluminum?


You're looking at a few really different materials, as far as machinability goes.

'Steel' usually refers to low carbon content, plain vanilla material. SAE 1020 & A36 are a couple of mild steels. Any steel with less than 25 carbon points (0.25%) cannot be hardened, no matter what you choose for machine settings, so a 'general machining' grade insert is fine.

Tool steel, or alloy steel, is tougher and needs an insert with a harder substrate that better supports the cutting edge. TiN coatings are common.

Titanium & stainless steel share many similarities - nearly the same material hardness, both generate tremendous heat at the cutting edge, both will work harden in the blink of an eye, both try to build up on the cutting edge. An even harder substrate is needed, along with a high temp coating like TiAlN.

Aluminum is the softest of the bunch, but it's sticky or gummy, and wants to build up on the edge. Aluminum inserts are often highly polished, and have a sharp, high positive rake face. If you ever machine aluminum with one of these, you'll never use anything else.

See what you can find on eBay, since you won't be out much if a particular choice doesn't work as well as expected. One good source for new inserts (in certain shapes & sizes) is http://www.latheinserts.com/main.sc Service is pretty fast, price is low compared to retail, and they stock quite a few specialty inserts.


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## StrikerDown (Feb 17, 2009)

Barry,

Are the CNMG inserts you use like the ones that come with the tool holder that Will got? 

Are the "special shinny" ones he also picked up what you suggest for aluminum?

If I were to pick up one of those Holder/Insert sets is the shank something I can mill down on my RF 31?

Thanks,

Ray


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## precisionworks (Feb 17, 2009)

Ray,

That's exactly the insert size & shape that goes in the tool holder Will purchased. I purchased a package of ten "aluminum specific" inserts from latheinserts.com (Will got a package also). 

http://www.latheinserts.com/category.sc?categoryId=43

The tool holder shanks are both hard & tough, which means that HSS end mills - even M42 Cobalt - will not work. You'll need either a solid carbide end mill, of a face mill with carbide inserts. I ran my 2" face mill at 350 rpm, .100" DOC, slow feed, and the chips were nicely blue You may want to try .050" DOC just to see how it feels, then move up to .075" or .100" as you get used to the operation.

A top brand tool holder (Iscar, Kenna, Valenite, Dolfa, etc.) is almost as tough to mill as a chunk of Ti-6-4:huh:


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## StrikerDown (Feb 17, 2009)

Might just pick up one of the tool holders, it's like a free holder with a pack of inserts. 

Those aluminum specific insert are a bit spendy compared to eBay's stuff. The inserts that come with the holder are not alum specific but will they work OK on alum with maybe a little bue?

Ray


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## precisionworks (Feb 17, 2009)

> not alum specific but will they work OK on alum with maybe a little bue?


They'll work fine, and I used to run a general machining insert on aluminum before the special inserts came out. The Al insert cuts with less pressure on the work, which can help on some jobs where the part is stuck out from the chuck & you can't use a steady rest or tailstock support. In most aluminum alloys, it provides a broken chip, instead of the long unbroken curl from a normal insert. You can still get BUE in some alloys, depending on machine settings, but the buildup is less than with a regular insert.


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## StrikerDown (Feb 17, 2009)

Cool, thats what I was hoping for, trying to keep costs down til I get some of the big hardware paid for.

My indexable insert face mill arrived today so I should be all set for when the mill arrives and gets set up! 

I've never run a mill before so this should be fun! 

lovecpf

Thanks Barry.

Ray


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