Series 21 - Classic V-Belt Fixed Center Drives
7C - 8-1-C, 7M - 8-1-M & 750 Control
 
Speed Selector home page

M-type spring loaded pulley
 
7M
8-1-M
Belt Size
A
B
B
C
Max P.D.
6.75
6.7
7.78
7.7
Min P.D.
2.4
2.5
2.8
3.0
A
2-9/16
2-17/32
3-5/16
3-3/16
B
2-1/16
2
2-5/8
2-1/2
D
7
8-1/8
E
3
3-5/8
G
2-3/8
2-7/8
L
4-21/32
6-7/16
Std. Bore
5/8 | 3/4, 7/8, 1 | 1-1/8
7/8 | 1 | 1-1/8, 1-1/4 | 1-3/8
Keyway
3/16 | 3/16 | 1/4
3/16 | 1/4 | 1/4 | 1/4
Bore Depth
2-1/2 | 3 | 3
3 | 3 | 3-1/4 | 4
Max. Bore
1-1/8
1-3/8
Weight
5.5 lbs.
9.5 lbs.

C-type controllable pulley
 
7C
8-1-C
Belt Size
A
B
B
C
Max P.D.
6.75
6.7
7.78
7.7
Min P.D.
2.4
2.5
2.8
3.0
A
15/16
1
1-15/16
1-7/16
B
1-1/12
1-9/16
2
2-1/8
C
6-21/32
6-15/16
D
7
8-1/8
E
6-3/4
6-15/16
F
2-3/8
2-7/8
G
2-3/8
2-7/8
H
9/16
13/16
L
11-1/8
11-5/16
Std. Bore
7/8 | 1 | 1-1/8
7/8 | 1 | 1-1/8, 1-1/4 | 1-3/8
Keyway
3/16 | 3/16 | 1/4
3/16 | 1/4 | 1/4 | 1/4
Bore Depth
2-5/8 | 2-5/8 | 2-5/8
3 | 3 | 3-1/4 | 4
Max. Bore
1-1/8
1-3/8
Weight
6.0 lbs.
8.5 lbs.