Indexable carbide inserts

[kd0afk]

I have been using hss but I'm starting to use indexable turning tooling. It is confusing and frustrating and I'm just talking about the triangle shaped ones.
I bought a set of five 1/2" turning tools and they take a triangular insert but I don't know which one. There are tcmt, tnmg, tnma and just when I start understanding the charts I see there is a "TT" style which doesn't show up on any chart. And to make matters worse, I measured the thickness of the insert and it doesn't match any of the inserts in the catalog. The charts don't tell you the length of one side (which I guess would make it too easy).
I measured from the center of the insert to one side and doubled it and I think the i.c. Is 3/8" but that's as far as I get.
Can someone tell me how to figure out which insert I would need for stainless steel for example?

 

[rodw]

Is this the kit you bought? The insrt code is in the product description otherwise check with your supplier.

 

[kd0afk]

There are different kits that use triangular inserts and I can't remember who I bought it from

 

[dave-in-england]

.

You can download the Sandvik .PDF catalogue which may give you an indication of which type of tip will fit your tool holders.

http://www2.coromant.sandvik.com/coromant/pdf/metalworking_products_061/main_a_1.pdf

.

 

[kd0afk]

How difficult is it to make in insert holder?

 

[Niels Abildgaard]

How difficult is it to make in insert holder?

http://www.homemodelenginemachinist.com/showthread.php?t=10175&page=2

Very easy and result is better than anything You can buy.

 

[rodw]

You don't even need to go to that trouble. You just need to have one flat edge to stop the insert from twisting. This was for a ball turner.

This also works well ( better actually) on a turning tool, just think about the geometry you use and set the angle accordingly.

 

[mc_n_g]

TT is TCMM but you will need to determine your size.
If your insert does not have a countersunk hole but has a chipbreaker then it is a TCMM. If it has a countersink and a chipbreaker is it TCMT.
I would advise you look up 'carbide insert chart' in Google and look at the images and webpages to determine the hows and what of the carbide alphabet.
There is some very good information out there.
The last letter(4th one) tells you if the insert has a chipbreaker, if there is a hole, and if the hole has a countersink and the type of countersink.
The first number is the inscribed circle diameter,
The second number is the thickness in 1/16" (2 = .125; 3 = .187; 2.5 = .156; etc)
The third number is the nose radius is 1/64"

In general cheap inserts will normally end up giving you cheap results. They can be brittle and break the tips easier.
If your number 1 nose is snapping try a 2 nose.
Only use C5 or C6 on steels and stainless. Use C2 on nonferrous.
C6 is finishing and normally does not handle larger cuts well.