Abrasive Types:

 

A = aluminum oxide

C = silicon carbide

Z = aluminum-zirconium oxide

Bond Type:

B = resinoid

BF = resinoid reinforced

O = oxychloride

R = rubber

RF = rubber reinforced

S = silicate

V = vitrified

SG = seeded gel

Abrasive Size:

Coarse: 8, 10, 12, 14, 16, 20 and 24 grit

Medium: 30, 36, 46, 54, 60

Fine: 70, 80, 90, 100, 120, 150, 180

Very Fine: 220, 240, 280, 320, 400, 500, 600

Grade Scale:

ABCDEFGHIJKLMNOPQRSTUVWXYZ

Soft...........Medium..............Hard
High Speed..................Mild Steel
Steel

Structure:

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Dense........................................ Open

So, a A80H8V wheel is aluminum oxide, 80 grit, relatively soft, with a medium density of abrasives and is vitrified.

Preferences:

Mike Mahoney and Martin Pidgen use a 46G.
Stuart Batty uses 60 grit for gouges and 80 grit for scrapers

Speed of Grinder:

Mike M, Martin P, Stuart B and Bonnie Klein all use 3400 rpm grinders while Lyle Jamison and John Jordan use 1750 rpm.

From Stuart Batty:

never use side of wheel; don’t remove paper from side, and always stand to the side when you turn on the grinder