Originally Posted by DareBee Carbide is harder. So it can be ground to a sharper cutting edge. It also is way more ridgid (no cutter flex). The guys doing hard-milling even use carbide bodied insert cutters for their PVD inserts. |
The point I was making was that the carbide itself does not actually seem to be capable of doing any cutting, and I have noticed that when the Titanium Nitride (or whatever) coating wears off, it's cutting ability is almost gone. This leads me to believe that it must be an inferior grade of carbide (hardness wise) underneath.
I agree on rigidity, perhaps because carbide doesn't have the "ring" you get from steel - it seems more "dead" - this would be desirable.
I've heard that carbide tooling is made by the sintering process, and I would have thought that this would have made them much easier to break than steel.
Going way back, working on a centre lathe and manual milling machine, I remember using grey tungsten carbide tips ( insert type as opposed to cemented or brazed on) on both the lathe and mill, they appeared to me to be uncoated and I was able to sharpen them (very successfully) on a soft green stone, or on a diamond impregnated stone.
Nowadays this would be impossible on the coated modern inserts, and I realize that it would be highly impractical in a high volume CNC shop.
I guess what I'm really asking is, where to get those high grade uncoated carbide inserts we used to have? - (for my home workshop when I retire soon). I don't want to have to be paying out continually on replacements for chipped coated lathe insert/milling cutters when doing one off experiments.
These (in my opionion) are useless in this type of situation.
Any young salesmen that I ask, just stare blankly at me - "uncoated???
whaddyamean uncoated??"
