Here's a really cool trick I discovered while overthinking a solution for tungsten grinding.
It's just a small block of 1/2 Al with a 7/64 hole drilled in it and a pin vise. The grinder is a Home Depot 50.00 special.
I did 10 2% lanth's in 5 minutes. The block is not mounted so you just hold it with one hand and spin the pin vise with the other.