Ceramic vs. Carbide Sanding Mandrels

[scdiveteam]

Well, I got a Black ceramic cutting insert, and rubbed it with wet dry paper, all that happen was the paper went dull. I could not put any scratches against the finish on the insert.
With a Gold coated carbide insert, there was some change to the initial look of the coating. But did not manage to sand through it. On the linisher, I could easily cut through the gold coat on a corner and grind some of the carbide away, but with the Black Ceramic, it cut a slot through the belt, but did score the edge a little, but way less than the Gold coated carbide.

The next level is, can this Black Ceramic be purchased as a ring stock material?

Neil,

We can purchase it as a bushing to build the mandrels and have it ground to size with a special diamond grinding process.

I don't know if is black but it is the same material used for tooling.

I don't think this was available machine technology 30 years ago when TW had his made.

Rick

 

[conetip]

My best suggestion is to find a Silicon Carbide ceramic Black-NOT Grey) outer ring of a bearing, 22mm or 7/8
The Si3N4 (silicon Nitride) is not as hard,(most ceramic balls are Si3N4 , grey colour)
Silicon carbide had been made since the 1890's or so for sand paper a grinding wheels.
The only materials that are harder than the SC are diamond compounds.
The way the SC is made, determines it's hardness and tensile strength. The newer processes that are used to making ceramic, is now used in cutting tools. So explains why the insert was not effected by the paper. How to determine which grade is used in an outer bearing shell I do not know, but would take the assumption that if it requires a high hardness and high strength , it will be the better material. These bearings use the Si3N4 balls which are softer than the inner and outer races.
I did see that bushes are made for some turbo's and water pumps, but too big for what we want. I am sure some company is USA is making SC rings that could be used on mandrels. The only other product that is as hard is DLC diamond like coating. but have no data on that at all.