Carbide inserts for lathe tool

JoeyInCali said:
Looks like TCGT inserts.
They come in different corner radius too.
Or is that radii .
Joey~My English needs more learnin'~
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Don't remember....you tell me. I ordered the holder and 50 inserts at the same time from the same place. I'm good for a while. :)
 
conetip said:
While I do agree that a good grade of hss is very good, few now know how to properly sharpen and hone an edge. That aside, there are now very fine grain carbide grades now that will hone to an edge sharper than that achievable for hss. These inserts are used in the plastic seal turning industry, and are extremely sharp. So sharp, you can not rub your finger on the edge without being cut. Iscar in Israel make these special inserts. Maybe there are other companies also making the super sharp inserts for the seal industry as well.
In general , to use on woods and most plastics, get the ground inserts, will have a G in the code, like a CCGT Rhomboid ground insert , or TNGG Triangle ground insert.
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Thanks for the info. I'll look more into it. My knowledge appears not to be up to date. You are absolutely right that the steel is only as good as its edge. It has taken me a long time to get decent at sharpening/honing an edge. And a lot of wasted money. And a good bit of that because I blamed the equipment when the fault was the operator.
 
There area now some new grades of steel that is a hss with carbides in it. They need a special wheel that is a combination of a cbn and diamond, and requires wet grinding or it requires to be edm ground. These materials hold a better edge than traditional hss. But don't have the longevity of the modern carbides, but are used mainly in the knife making and specialised punch and die tools.
 
Well i learned some things and see some possible options as far as wood-turning/cue-making. Thanks for that! :)

On the topic drift re: cutting materials and edge tools.....

There area now some new grades of steel that is a hss with carbides in it.
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All tool steel has carbides in it. Managing them is the crux of tool making. Carbides make the tool brittle, but contribute to longer wear. So heat treating is fundamentally a method of trying to make them very small, and put them in a distribution/% that allows the edge to still be tough enough. I use CPM M4 for some of the woodworking tools i make because the "powdered metallurgy" process makes for fine grains and a tougher edge at the same hardness. Modified by the specific range of hardening and tempering temperatures. (You can harden for max hardness, or give up a smidgeon/ 2 points Rc of absolute hardness and maximize toughness, or somewhere in between).

The idea in an edge tool is that you want enough hardness (hardness is a proxy for tensile strength) so the edge does not fold/bend. But not so much that it is chippy when used in the intended substrate. Carbides add to wear resistance, which is not directly related to hardness; but both tend to make the edge more brittle.

I love commercially made CPM M4 tool bits for my planer when cutting steel. Carbide still can't give anywhere close to the same finish or step over, and often fails by chipping long before the HSS dulls. I do use carbide on harder steels and weldments when the step-over (feed) is small. But gosh, what a time waster (the small steps/higher HP drain of carbide)

OK. back to cues.
:grin-square:

smt
 
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I use an indexable carbide cut off tool. Super sharp and and has super tight corner. I don't want say 90 degrees because it's not as it has a positive cut which allows to get into the shoulder area.

Thanks Ed.
 
This pdf is worth downloading and reading. Explains feed rates, surface finish values etc, also covers wiper insert technology a little. You can create your own wiper insert technology by honing a very small flat on the insert. But then the holder and insert need to be aligned accurately to the flat generated. The easy way is to hone the insert in position on the holder. Large volume shops are using PCD technologies and well. There are pcd inserts that are EDM ground with very sharp geometries and cut wood very well and cool. Cool cutting is a very key aspect that is often over looked. In the VCGX range, are available in the 11, (VCGX110304 AL) and the 16, (VCGX160404 AL) A VCGX will generally fit into a VBGX holder but not normally the other way around. Ideally you should have the correct holder for the insert side angle grade.


https://www.doriantool.com/wp-content/uploads/dorian_tool_TurningTools_CarbideInserts_.pdf
 
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