Cutting carbide

[BMad]

Im going to try cutting down an old 3/4 carbide endmill into a ring. Does anyone know if I can cut carbide with carbide or do i need a special tool? Also does anyone know the proper feeds and speeds for it?

Thank you

[jasminder]

as i know about carbides,you cannot cut carbides with carbides,
i use a diamond wheel to cut carbide ,not to cut actually to shape it .

it is a copper wheel with diamond abbrasive just like the diamond dressers for ginders.

[Adamj12b]

My experience with this is, if you have a higher grade carbide as a too it can cut the old end mill, but if its lower, the old end mill will just dull the new cutter in seconds.

-Adam

[beege]

I'd get the hole EDMed out, then finish it with a grinder, CBN or Diamond. Tried turning carbide once with a diamond tool (at the expense of Kennametal, i think it was,,,). Setup wasn't rigid enough. But they told me it could b done.

[CarbideBob]

The only time you can cut carbide is before it's been sintered (whats known as the green state).
Once it's been cooked forget it.

CBN does not grind carbide well, PCD won't cut it either.
It has to be ground with diamond wheels. If you spin it fast enough (3000-5000 SFM) you can use a natural diamond point and somewhat cut it.
Essentially you are grinding with a single point tool.

If you really want to do this you'll need to cut it off with a diamond cut-off wheel and have the hole EDMed in. Grind the ID if you want a smooth finish. This takes a very high speed spindle because the grinding wheel is so small.
If you have enough time on your hands you could lap the inside smooth with diamond paste and a soft steel pin.

Carbide rings are normally molded to size with .010 grind stock, then finish ground and polished.
Bob

[Andre' B]

The only time you can cut carbide is before it's been sintered (whats known as the green state).
Once it's been cooked forget it.

While you could argue that this is a grinding process. The cutting speeds used are very slow compared to those typically used in grinding.
http://news.thomasnet.com/fullstory/9875

[BMad]

Thank you guys for the help.

[dannystooblue]

If I were planning to create a ring from carbide to wear I would machine an electrode from a very high quality graphite and edm it 1/2 from each side leaving the ring complete except the polishing, then I would expect all polishing done with some diamond compound. I would either wire edm off the blank, grind it off, or just sink edm it off with a blade shaped electrode. The reason I would do it like this is because graphite is easy to machine and edm is very trouble free, the guy running the machine is most often capable of doing other things while it is running.


Danny

[MrWild]

If your finger swellsd, you won't be cutting this ring off like a normal ring could be cut.

[dannystooblue]

If your finger swellsd, you won't be cutting this ring off like a normal ring could be cut.

You would just hit it with a hammer, it would bust right off depending on the wall thickness of the remaining carbide.

Danny

[hndswthtshdws]

If your finger swellsd, you won't be cutting this ring off like a normal ring could be cut.

Carbide rings can be broken with vice grips. Hospitals know how to remove them if your worried about it.

[dannystooblue]

check out ebay for carbide rings, they sell in the neighborhood of $20


Danny