
Dimensions of Preferred Sizes of Type A Plain Washers
| Nominal Washer Size | Series(1) | A | B | C | ||||||
| Inside Diameter | Outside Diameter | Thickness | ||||||||
| Basic | Tolerance | Basic | Tolerance | |||||||
| Plus | Minus | Plus | Minus | Basic | Max | Min | ||||
| No. 0 (0.060) | ... | 0.078 | 0.000 | 0.005 | 0.188 | 0.000 | 0.005 | 0.020 | 0.025 | 0.016 |
| No. 2 (0.086) | ... | 0.094 | 0.000 | 0.005 | 0.250 | 0.000 | 0.005 | 0.020 | 0.025 | 0.016 |
| No. 4 (0.112) | ... | 0.125 | 0.008 | 0.005 | 0.312 | 0.008 | 0.005 | 0.032 | 0.040 | 0.025 |
| No. 6 (0.138) | ... | 0.156 | 0.008 | 0.005 | 0.375 | 0.015 | 0.005 | 0.049 | 0.065 | 0.036 |
| No. 8 (0.164) | ... | 0.188 | 0.008 | 0.005 | 0.438 | 0.015 | 0.005 | 0.049 | 0.065 | 0.036 |
| No. 10 (0.190) | ... | 0.219 | 0.008 | 0.005 | 0.500 | 0.015 | 0.005 | 0.049 | 0.065 | 0.036 |
| 3/16 (0.188) | ... | 0.250 | 0.015 | 0.005 | 0.562 | 0.015 | 0.005 | 0.049 | 0.065 | 0.036 |
| No. 12 (0.216) | ... | 0.250 | 0.015 | 0.005 | 0.562 | 0.015 | 0.005 | 0.065 | 0.080 | 0.051 |
| 1/4 (0.250) | N | 0.281 | 0.015 | 0.005 | 0.625 | 0.015 | 0.005 | 0.065 | 0.080 | 0.051 |
| 1/4 (0.250) | W | 0.312 | 0.015 | 0.005 | 0.734(2) | 0.015 | 0.007 | 0.065 | 0.080 | 0.051 |
| 5/16 (0.312) | N | 0.344 | 0.015 | 0.005 | 0.688 | 0.015 | 0.007 | 0.065 | 0.080 | 0.051 |
| 5/16 (0.312) | W | 0.375 | 0.015 | 0.005 | 0.875 | 0.030 | 0.007 | 0.083 | 0.104 | 0.064 |
| 3/8 (0.375) | N | 0.406 | 0.015 | 0.005 | 0.812 | 0.015 | 0.007 | 0.065 | 0.080 | 0.051 |
| 3/8 (0.375) | W | 0.438 | 0.015 | 0.005 | 1.000 | 0.030 | 0.007 | 0.083 | 0.104 | 0.064 |
| 7/16 (0.438) | N | 0.469 | 0.015 | 0.005 | 0.922 | 0.015 | 0.007 | 0.065 | 0.080 | 0.051 |
| 7/16 (0.438) | W | 0.500 | 0.015 | 0.005 | 1.250 | 0.030 | 0.007 | 0.083 | 0.104 | 0.064 |
| 1/2 (0.500) | N | 0.531 | 0.015 | 0.005 | 1.062 | 0.030 | 0.007 | 0.095 | 0.121 | 0.074 |
| 1/2 (0.500) | W | 0.562 | 0.015 | 0.005 | 1.375 | 0.030 | 0.007 | 0.109 | 0.132 | 0.086 |
| 9/16 (0.562) | N | 0.594 | 0.015 | 0.005 | 1.156(2) | 0.030 | 0.007 | 0.095 | 0.121 | 0.074 |
| 9/16 (0.562) | W | 0.625 | 0.015 | 0.005 | 1.469(2) | 0.030 | 0.007 | 0.109 | 0.132 | 0.086 |