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Parallel Key and Keyway Sizes and Tolerances

Last updated:18 June 2019

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JIS (Excerpt from JIS B 1301-1996)Unit [mm]

Nominal key size b × h Applied shaft diameter d Key size Keyway size
b h c or r Standard size of b1 and b2 Tightening type Normal type r1 and r2 t1 t2
Standard size Tolerance （h9） Standard size Tolerance b1/b2 tolerance（P9） b1 tolerance（N9） b2 tolerance（Js9） Standard size Tolerance Standard size Tolerance
2×2 6~8 2 0      
-0.025		 2 0      
-0.025		 h9 0.16~0.25 2 -0.006 -0.031 -0.004 -0.029 ±0.0125 0.08~0.16 1.2 +0.1
0 		 1.0 +0.1
0 
3×3 8~10 3 3 3 1.8 1.4
4×4 10~12 4 0      
-0.030		 4 0      
-0.030		 4 -0.012 -0.042 0      
-0.030		 ±0.0150 2.5 1.8
5×5 12~17 5 5 0.25~0.40 5 0.16~0.25 3.0 2.3
6×6 17~22 6 6 6 3.5 2.8
8×7 22~30 8 0      
-0.036		 7 0      
-0.090		 h11 8 -0.015 -0.051 0      
-0.036		 ±0.0180 4.0 +0.2
0     		 3.3 +0.2
0     
10×8 30~38 10 8 0.40~0.60 10 0.25~0.40 5.0 3.3
12×8 38~44 12 0      
-0.043		 8 12 -0.018 -0.061 0      
-0.043		 ±0.0215 5.0 3.3
14×9 44~50 14 9 14 5.5 3.8
16×10 50~58 16 10 16 6.0 4.3
18×11 58~65 18 11 0      
-0.110		 18 7.0 4.4
20×12 65~75 20 0      
-0.052		 12 0.60~0.80 20 -0.022 -0.074 0      
-0.052		 ± 0.0260 0.40~0.60 7.5 4.9
22×14 75~85 22 14 22 9.0 5.4
25×14 85~95 25 14 25 9.0 5.4
28×16 95~110 28 16 28 10.0 6.4
32×18 110~130 32 0      
-0.062		 18 32 -0.026 -0.088 0      
-0.062		 ±0.0310 11.0 7.4

Old JIS

Old JIS Class 1 (Excerpt from JIS B 1301-1959) Unit [mm]

Nominal key size b × h Applied shaft diameter d Key size Keyway size
b h c or r Standard size of b1 and b2 b1 tolerance （H8） b2 tolerance （F7） r1 and r2 t1 t2
Standard size Tolerance（p7） Standard size Tolerance （h9） Standard size Tolerance Standard size Tolerance
4×4 10 or more and 13 or below 4 +0.024 +0.012 4 0      
-0.030		 0.5 4 +0.018
0     		 +0.022 +0.010 0.4 2.5 +0.05
0   		 1.5 +0.05
0   
5×5 Over 13 and 20 or below 5 5 5 3 2
7×7 Over 20 and 30 or below 7 +0.030 +0.015 7 0      
-0.036		 7 +0.022
0     		 +0.028 +0.013 4 3
10×8 Over 30 and 40 or below 10 8 0.8 10 0.6 4.5 3.5
12×8 Over 40 and 50 or below 12 +0.036 +0.018 8 12 +0.027
0     		 +0.034 +0.016 4.5 3.5
15×10 Over 50 and 60 or below 15 10 15 5 5
18×12 Over 60 and 70 or below 18 12 0      
-0.043		 1.2 18 1.0 6 6
20×13 Over 70 and 80 or below 20 +0.043 +0.022 13 20 +0.033
0     		 +0.041 +0.020 7 6
24×16 Over 80 and 95 or below 24 16 24 8 8
28×18 Over 95 and 110 or below 28 18 28 9 9
32×20 Over 110 and 125 or below 32 +0.051 +0.026 20 0      
-0.052		 2 32 +0.039
0     		 +0.050 +0.025 1.6 10 10

Old JIS Class 2 (Excerpt from JIS B 1301-1959) Unit [mm]

Nominal key size b × h Applied shaft diameter d Key size Keyway size
b h c or r Standard size of b1 and b2 b1Tolerance （h9） b2 tolerance （E9） r1 and r2 t1 t2
Standard size Tolerance（h8） Standard size Tolerance(h10) Standard size Tolerance Standard size Tolerance
4×4 10 or more and 13 or below 4 0      
-0.018		 4 0      
-0.048		 0.5 4 +0.030
0     		 +0.050 +0.020 0.4 2.5 +0.1
0 		 1.5 +0.1
0 
5×5 Over 13 and 20 or below 5 5 5 3 2
7×7 Over 20 and 30 or below 7 0      
-0.022		 7 0      
-0.058		 7 +0.036
0     		 +0.061 +0.025 4 3
10×8 Over 30 and 40 or below 10 8 0.8 10 0.6 4.5 3.5
12×8 Over 40 and 50 or below 12 0      
-0.027		 8 12 +0.043
0     		 +0.075 +0.032 4.5 3.5
15×10 Over 50 and 60 or below 15 10 15 5 5
18×12 Over 60 and 70 or below 18 12 0      
-0.070		 1.2 18 1.0 6 6
20×13 Over 70 and 80 or below 20 0      
-0.033		 13 20 +0.052
0     		 +0.092 +0.040 7 6
24×16 Over 80 and 95 or below 24 16 24 8 8
28×18 Over 95 and 110 or below 28 18 28 9 9
32×20 Over 110 and 125 or below 32 0      
-0.039		 20 0      
-0.084		 2 32 +0.062
0     		 +0.112 +0.050 1.6 10 10

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