Series 21 - Classic V-Belt Fixed Center Drives
3C - 6C, 3M - 6M, & 350 Control
 
Speed Selector home page

M-type spring loaded pulley
3M
4M
5M
6M
A
1-21-32
1-7/16
1-11/16
2-1/8
B
1-1/2
1-9/32
1-3/8
1-3/4
C
1-1/4
1-11/16
1-11/16
2-1/4
D
3-1/8
4
5
6
E
1-7/8
2-3/16
2-15/16
3-13/16
L
2-7/16
2-1/4
3-5/8
4-11/16
Std. Bore
1/2 | 5/8
1/2 | 5/8, 3/4
1/2 | 5/8, 3/4
5/8 | 3/4, 7/8 | 1
Keyway
1/8 | 3/16
1/8 | 3/16
1/8 | 3/16
3/16 | 3/16 | 1/4
Bore Depth
Through
Through
Through
2-1/2 | 3 | 3
Max. Bore
3/4
3/4
3/4
1
Belt Size
A
A
A
A
Max P.D.
2.8
3.7
4.7
5.7
Min P.D.
1.4
1.85
1.85
2.15
Weight
1 lb.
2.5 lbs.
2.375 lbs.
4.75 lbs.

C-type controllable pulley
3C
4C
5C
6C
A
3/4
3/4
3/4
7/8
B
29/32
15/16
1-1/8
1-5/16
C
3-7/16
3-3/4
4-7/8
5-1/2
D
3-1/8
4
5
6
E
3 Min.
3-1/4 Min.
4-3/8 Min.
5 Min.
F
1-1/4
1-1/2
1-1/2
2-3/8
H
3/8
3/8
3/8
1/2
L
7
7-1/4
8-3/8
9
Std. Bore
1/2 | 5/8
1/2 | 5/8, 3/4
1/2 | 5/8, 3/4
1/2, 5/8, 3/4,
7/8 | 1
Keyway
1/8 | 3/16
1/8 | 3/16
1/8 | 3/16
3/16 | 1/4
Bore Depth
2-1/8
2-3/8
3
3-5/8
Max. Bore
3/4
3/4
3/4
1-1/8
Belt Size
A
A
A
A
Max P.D.
2.8
3.7
4.7
5.7
Min P.D.
1.4
1.85
1.85
2.15
Weight
1.5 lb.
2.75 lbs.
2.5 lbs.
4.75 lbs.