1/4 inch wheels
M
1/8 inch wheels
N
O
4-1/2 inch (115mm) Grinding Wheels
Type 27 guard
Unthreaded backing flange
Type 27 depressed center
wheel
Threaded clamp nut
Threaded clamp nut
Backing flange
Threaded clamp nut
Backing flange
20˚-30˚
Type 27 guard
Type 27 hubbed wheel
P
Q
14
13
R
5˚- 15˚
4-1/2 inch (115mm) Sanding Flap Discs
Type 27 guard
Hubbed sanding flap disc
10
5˚- 10˚
8
S
5˚- 10˚
Type 27 guard
Unthreaded backing flange
non-hubbed sanding flap disc
Threaded clamp nut