Adjustable Center Drives
Series 21 Standard V-Belt Drives: 8-1-M

 
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8-1-M - 2.78:1 Speed Ratio
H.P.: 4 Motor Speed: 1800 RPM
H.P.: 2 1/2 Motor Speed: 1200 RPM
series 21 dimensional drawing
A
3-5/16
B
2-5/8
C
2-7/8
D
8-1/8
E
3-5/8
L
6-7/16
Std. bore
7/8 | 1 | 1-1/8 | 1-1/4 | 1-3/8
keyway
3/16 | 1/4 | 1/4 | 1/4
bore depth
3 | 3 | 3-1/4 | 4
max bore
1-3/8
belt size
B
max. p.d.
7.78
min p.d.
2.8
weight
9.5 lb.
Driven Speeds
Driven
Sheave
Pitch
Diameter
Belt vs Minimum Center Distance
1800 RPM Motor
1200 RPM Motor
B 26
B 31
B 35
B 38
B 46
B 55
B 68
B 80
B 85
B 96
B 105
Max.
Min.
Max.
Min.
2005
721
1336
480
7.0
10.3
12.3
14.8
16.8
19.3
23.3
26.8
29.8
31.8
37.8
41.8
1755
631
1170
420
8.0
9.5
11.5
14.0
16.0
18.5
22.5
26.0
29.0
31.0
37.0
41.0
1560
561
1040
376
9.0
10.7
13.2
15.2
17.7
21.7
25.2
28.2
30.2
36.2
40.2
1400
503
933
335
10.0
9.9
12.4
14.4
16.9
20.9
24.4
27.4
29.4
35.4
39.4
1276
459
850
305
11.0
11.5
13.6
16.1
20.1
23.6
26.6
28.6
34.6
38.6
1170
420
780
280
12.0
12.7
15.2
19.3
22.8
25.8
27.8
33.8
37.8
936
336
624
224
15.0
12.5
16.6
20.2
23.2
25.3
31.3
35.3
780
280
520
187
18.0
13.7
12.4
20.5
22.6
28.7
32.8

WARNING: All open belt drives must be adequately guarded for personal safety during operation.