1915 carbo

[Baldy]

I seem to have developed a barber hone aquisition dissorder lately (3 this month). Its not my fault, you dont see many on ebay in Australia but lately there has been a few and no one else seems to want them so I've got them pretty cheap.
Anyway just wondering if anybody can tell me anything about this one. It was a little dished in the middle and man it took a while to lap it. Very hard from my limited experience.

 

[SliceOfLife]

I'd assume it's carborundum. No clue who made it, but as you noted, very, very, very hard. The high grit ones are painful to lap (worse than swaty's in my experience. Carborundum is a bit harder than Corundum as I recall.