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ASME B18.22.1 Type B Plain Washers

ASME B18.22.1 standard covers two types of general purpose plain washers designated as Type B.
The inclusion of dimensional data in ASME B18.22.1 standard is not intended to imply that all of the products described herein are production items. Consumers are requested to consult with manufacturers concerning lists of stock production sizes.

ASME B18.22.1 Type B Plain Washers

ASME B18.22.1 Type B Plain Washers Dimensions (mm)

Nominal Size Series Inside Diameter, A Outside Diameter, B Thickness, C
Basic Max. Min. Basic Max. Min. Basic Max. Min.
5/16 0.312 Narrow 8.737 18.414 5.512 15.875 25.552 12.65 1.6 45.796 36.118
5/16 0.312 Regular 8.737 18.414 5.512 22.225 31.902 17.704 1.6 45.796 36.118
5/16 0.312 Wide 8.737 18.414 5.512 28.575 38.252 24.054 1.6 45.796 36.118
3/8 0.375 Narrow 10.312 19.989 7.087 18.643 28.32 14.122 1.6 45.796 36.118
3/8 0.375 Regular 10.312 19.989 7.087 25.4 35.077 20.879 1.6 45.796 36.118
3/8 0.375 Wide 10.312 19.989 7.087 31.75 51.104 27.229 2.54 72.263 58.064
7/16 0.438 Narrow 11.912 21.589 8.687 22.225 31.902 17.704 1.6 45.796 36.118
7/16 0.438 Regular 11.912 21.589 8.687 28.575 38.252 24.054 1.6 45.796 36.118
7/16 0.438 Wide 11.912 21.589 8.687 37.312 56.666 32.791 2.54 72.263 58.064
1/2 0.5 Narrow 13.487 23.164 10.262 25.4 35.077 20.879 1.6 45.796 36.118
1/2 0.5 Regular 13.487 23.164 10.262 31.75 51.104 27.229 2.54 72.263 58.064
1/2 0.5 Wide 13.487 23.164 10.262 44.45 63.804 39.929 2.54 72.263 58.064
9/16 0.562 Narrow 15.087 24.764 11.862 28.575 38.252 24.054 1.6 45.796 36.118
9/16 0.562 Regular 15.087 24.764 11.862 37.312 56.666 32.791 2.54 72.263 58.064
9/16 0.562 Wide 15.087 24.764 11.862 50.8 70.154 46.279 2.54 72.263 58.064
5/8 0.625 Narrow 16.662 36.016 12.141 31.75 51.104 27.229 2.54 72.263 58.064
5/8 0.625 Regular 16.662 36.016 12.141 44.45 63.804 39.929 2.54 72.263 58.064
5/8 0.625 Wide 16.662 36.016 12.141 57.15 76.504 52.629 4.064 112.369 94.183
3/4 0.75 Narrow 20.624 39.978 16.103 34.925 54.279 30.404 2.54 72.263 58.064
3/4 0.75 Regular 20.624 39.978 16.103 50.8 70.154 46.279 2.54 72.263 58.064
3/4 0.75 Wide 20.624 39.978 16.103 63.5 82.854 58.979 4.064 112.369 94.183
7/8 0.875 Narrow 23.825 43.179 19.304 37.312 56.666 32.791 2.54 72.263 58.064
7/8 0.875 Regular 23.825 43.179 19.304 57.15 76.504 52.629 4.064 112.369 94.183
7/8 0.875 Wide 23.825 43.179 19.304 69.85 89.204 65.329 4.064 112.369 94.183
1 1 Narrow 26.974 46.328 22.453 44.45 63.804 39.929 2.54 72.263 58.064
1 1 Regular 26.974 46.328 22.453 63.5 82.854 58.979 4.064 112.369 94.183
1 1 Wide 26.974 46.328 22.453 76.2 95.554 71.679 4.064 112.369 94.183
11/8 1.125 Narrow 30.175 49.529 25.654 50.8 70.154 46.279 2.54 72.263 58.064
11/8 1.125 Regular 30.175 49.529 25.654 69.85 89.204 65.329 4.064 112.369 94.183
11/8 1.125 Wide 30.175 49.529 25.654 82.55 101.904 78.029 4.064 112.369 94.183
11/4 1.25 Narrow 33.324 52.678 28.803 57.15 76.504 52.629 4.064 112.369 94.183
11/4 1.25 Regular 33.324 52.678 28.803 76.2 95.554 71.679 4.064 112.369 94.183
11/4 1.25 Wide 33.324 62.356 26.873 88.9 117.932 82.449 6.35 171.602 150.977
13/8 1.375 Narrow 36.525 55.879 32.004 63.5 82.854 58.979 4.064 112.369 94.183
13/8 1.375 Regular 36.525 55.879 32.004 82.55 101.904 78.029 4.064 112.369 94.183
13/8 1.375 Wide 36.525 65.557 30.074 95.25 124.282 88.799 6.35 171.602 150.977
11/2 1.5 Narrow 39.674 59.028 35.153 69.85 89.204 65.329 4.064 112.369 94.183
11/2 1.5 Regular 39.674 68.706 33.223 88.9 117.932 82.449 6.35 171.602 150.977
11/2 1.5 Wide 39.674 68.706 33.223 101.6 130.632 95.149 6.35 171.602 150.977
15/8 1.625 Narrow 44.45 63.804 39.929 76.2 95.554 71.679 4.064 112.369 94.183
15/8 1.625 Regular 44.45 73.482 37.999 95.25 124.282 88.799 6.35 171.602 150.977
15/8 1.625 Wide 44.45 73.482 37.999 107.95 136.982 101.499 6.35 171.602 150.977
13/4 1.75 Narrow 47.625 66.979 43.104 82.55 101.904 78.029 4.064 112.369 94.183
13/4 1.75 Regular 47.625 76.657 41.174 101.6 130.632 95.149 6.35 171.602 150.977
13/4 1.75 Wide 47.625 76.657 41.174 114.3 143.332 107.849 6.35 171.602 150.977
17/8 1.875 Narrow 50.8 79.832 44.349 88.9 117.932 82.449 6.35 171.602 150.977
17/8 1.875 Regular 50.8 79.832 44.349 107.95 136.982 101.499 6.35 171.602 150.977
17/8 1.875 Wide 50.8 79.832 44.349 120.65 149.682 114.199 6.35 171.602 150.977
2 2 Narrow 53.975 83.007 47.524 95.25 124.282 88.799 6.35 171.602 150.977
2 2 Regular 53.975 83.007 47.524 114.3 143.332 107.849 6.35 171.602 150.977
2 2 Wide 53.975 83.007 47.524 127 156.032 120.549 6.35 171.602 150.977
21/4 2.25 Narrow 60.325 89.357 53.874 101.6 130.632 95.149 6.35 171.602 150.977
21/4 2.25 Regular 60.325 89.357 53.874 127 156.032 120.549 6.35 171.602 150.977
21/4 2.25 Wide 60.325 102.26 53.874 139.7 181.635 133.249 9.525 253.542 230.327
21/2 2.5 Narrow 66.675 95.707 60.224 114.3 143.332 107.849 6.35 171.602 150.977
21/2 2.5 Regular 66.675 108.61 60.224 139.7 181.635 133.249 9.525 253.542 230.327
21/2 2.5 Wide 66.675 108.61 60.224 152.4 194.335 145.949 9.525 253.542 230.327
23/4 2.75 Narrow 73.025 102.057 66.574 127 156.032 120.549 6.35 171.602 150.977
23/4 2.75 Regular 73.025 114.96 66.574 152.4 194.335 145.949 9.525 253.542 230.327
23/4 2.75 Wide 73.025 114.96 66.574 165.1 207.035 158.649 9.525 253.542 230.327
3 3 Narrow 79.375 121.31 72.924 139.7 181.635 133.249 9.525 253.542 230.327
3 3 Regular 79.375 121.31 72.924 165.1 207.035 158.649 9.525 253.542 230.327
3 3 Wide 79.375 121.31 72.924 177.8 219.735 171.349 9.525 253.542 230.327
  • a Nominal washer sizes are intended for use with comparable nominal screw or bolt sizes.
  • b N indicates Narrow; R, Regular; and W, Wide Series.
  • c The 18.644 mm and 37.313 mm outside diameter avoids washers which could be used in coin operated devices.
  • All dimensions are in millimeters.
  • Inside and outside diameters shall be concentric within at least the inside diameter tolerance.
  • Washers shall be flat within 0.127 mm for basic outside diameters up through 22.225 mm and within 0.254 mm for larger outside diameters.
  • For 2 1/4-, 2 1/2- , 2 3/4-, and 3-inch sizes see ASME B18.22.1-1965 (R1998).

ASME B18.22.1 Type B Plain Washers Dimensions (Inch)

Nominal Size Series Inside Diameter, A Outside Diameter, B Thickness, C
Basic Max. Min. Basic Max. Min. Basic Max. Min.
5/16 0.312 Narrow 0.34 0.725 0.217 0.63 1.006 0.498 0.06 1.803 1.422
5/16 0.312 Regular 0.34 0.725 0.217 0.88 1.256 0.697 0.06 1.803 1.422
5/16 0.312 Wide 0.34 0.725 0.217 1.13 1.506 0.947 0.06 1.803 1.422
3/8 0.375 Narrow 0.41 0.787 0.279 0.73 1.115 0.556 0.06 1.803 1.422
3/8 0.375 Regular 0.41 0.787 0.279 1.00 1.381 0.822 0.06 1.803 1.422
3/8 0.375 Wide 0.41 0.787 0.279 1.25 2.012 1.072 0.10 2.845 2.286
7/16 0.438 Narrow 0.47 0.850 0.342 0.88 1.256 0.697 0.06 1.803 1.422
7/16 0.438 Regular 0.47 0.850 0.342 1.13 1.506 0.947 0.06 1.803 1.422
7/16 0.438 Wide 0.47 0.850 0.342 1.47 2.231 1.291 0.10 2.845 2.286
1/2 0.5 Narrow 0.53 0.912 0.404 1.00 1.381 0.822 0.06 1.803 1.422
1/2 0.5 Regular 0.53 0.912 0.404 1.25 2.012 1.072 0.10 2.845 2.286
1/2 0.5 Wide 0.53 0.912 0.404 1.75 2.512 1.572 0.10 2.845 2.286
9/16 0.562 Narrow 0.59 0.975 0.467 1.13 1.506 0.947 0.06 1.803 1.422
9/16 0.562 Regular 0.59 0.975 0.467 1.47 2.231 1.291 0.10 2.845 2.286
9/16 0.562 Wide 0.59 0.975 0.467 2.00 2.762 1.822 0.10 2.845 2.286
5/8 0.625 Narrow 0.66 1.418 0.478 1.25 2.012 1.072 0.10 2.845 2.286
5/8 0.625 Regular 0.66 1.418 0.478 1.75 2.512 1.572 0.10 2.845 2.286
5/8 0.625 Wide 0.66 1.418 0.478 2.25 3.012 2.072 0.16 4.424 3.708
3/4 0.75 Narrow 0.81 1.574 0.634 1.38 2.137 1.197 0.10 2.845 2.286
3/4 0.75 Regular 0.81 1.574 0.634 2.00 2.762 1.822 0.10 2.845 2.286
3/4 0.75 Wide 0.81 1.574 0.634 2.50 3.262 2.322 0.16 4.424 3.708
7/8 0.875 Narrow 0.94 1.700 0.760 1.47 2.231 1.291 0.10 2.845 2.286
7/8 0.875 Regular 0.94 1.700 0.760 2.25 3.012 2.072 0.16 4.424 3.708
7/8 0.875 Wide 0.94 1.700 0.760 2.75 3.512 2.572 0.16 4.424 3.708
1 1 Narrow 1.06 1.824 0.884 1.75 2.512 1.572 0.10 2.845 2.286
1 1 Regular 1.06 1.824 0.884 2.50 3.262 2.322 0.16 4.424 3.708
1 1 Wide 1.06 1.824 0.884 3.00 3.762 2.822 0.16 4.424 3.708
11/8 1.125 Narrow 1.19 1.950 1.010 2.00 2.762 1.822 0.10 2.845 2.286
11/8 1.125 Regular 1.19 1.950 1.010 2.75 3.512 2.572 0.16 4.424 3.708
11/8 1.125 Wide 1.19 1.950 1.010 3.25 4.012 3.072 0.16 4.424 3.708
11/4 1.25 Narrow 1.31 2.074 1.134 2.25 3.012 2.072 0.16 4.424 3.708
11/4 1.25 Regular 1.31 2.074 1.134 3.00 3.762 2.822 0.16 4.424 3.708
11/4 1.25 Wide 1.31 2.455 1.058 3.50 4.643 3.246 0.25 6.756 5.944
13/8 1.375 Narrow 1.44 2.200 1.260 2.50 3.262 2.322 0.16 4.424 3.708
13/8 1.375 Regular 1.44 2.200 1.260 3.25 4.012 3.072 0.16 4.424 3.708
13/8 1.375 Wide 1.44 2.581 1.184 3.75 4.893 3.496 0.25 6.756 5.944
11/2 1.5 Narrow 1.56 2.324 1.384 2.75 3.512 2.572 0.16 4.424 3.708
11/2 1.5 Regular 1.56 2.705 1.308 3.50 4.643 3.246 0.25 6.756 5.944
11/2 1.5 Wide 1.56 2.705 1.308 4.00 5.143 3.746 0.25 6.756 5.944
15/8 1.625 Narrow 1.75 2.512 1.572 3.00 3.762 2.822 0.16 4.424 3.708
15/8 1.625 Regular 1.75 2.893 1.496 3.75 4.893 3.496 0.25 6.756 5.944
15/8 1.625 Wide 1.75 2.893 1.496 4.25 5.393 3.996 0.25 6.756 5.944
13/4 1.75 Narrow 1.88 2.637 1.697 3.25 4.012 3.072 0.16 4.424 3.708
13/4 1.75 Regular 1.88 3.018 1.621 4.00 5.143 3.746 0.25 6.756 5.944
13/4 1.75 Wide 1.88 3.018 1.621 4.50 5.643 4.246 0.25 6.756 5.944
17/8 1.875 Narrow 2.00 3.143 1.746 3.50 4.643 3.246 0.25 6.756 5.944
17/8 1.875 Regular 2.00 3.143 1.746 4.25 5.393 3.996 0.25 6.756 5.944
17/8 1.875 Wide 2.00 3.143 1.746 4.75 5.893 4.496 0.25 6.756 5.944
2 2 Narrow 2.13 3.268 1.871 3.75 4.893 3.496 0.25 6.756 5.944
2 2 Regular 2.13 3.268 1.871 4.50 5.643 4.246 0.25 6.756 5.944
2 2 Wide 2.13 3.268 1.871 5.00 6.143 4.746 0.25 6.756 5.944
21/4 2.25 Narrow 2.38 3.518 2.121 4.00 5.143 3.746 0.25 6.756 5.944
21/4 2.25 Regular 2.38 3.518 2.121 5.00 6.143 4.746 0.25 6.756 5.944
21/4 2.25 Wide 2.38 4.026 2.121 5.50 7.151 5.246 0.38 9.982 9.068
21/2 2.5 Narrow 2.63 3.768 2.371 4.50 5.643 4.246 0.25 6.756 5.944
21/2 2.5 Regular 2.63 4.276 2.371 5.50 7.151 5.246 0.38 9.982 9.068
21/2 2.5 Wide 2.63 4.276 2.371 6.00 7.651 5.746 0.38 9.982 9.068
23/4 2.75 Narrow 2.88 4.018 2.621 5.00 6.143 4.746 0.25 6.756 5.944
23/4 2.75 Regular 2.88 4.526 2.621 6.00 7.651 5.746 0.38 9.982 9.068
23/4 2.75 Wide 2.88 4.526 2.621 6.50 8.151 6.246 0.38 9.982 9.068
3 3 Narrow 3.13 4.776 2.871 5.50 7.151 5.246 0.38 9.982 9.068
3 3 Regular 3.13 4.776 2.871 6.50 8.151 6.246 0.38 9.982 9.068
3 3 Wide 3.13 4.776 2.871 7.00 8.651 6.746 0.38 9.982 9.068
  • a Nominal washer sizes are intended for use with comparable nominal screw or bolt sizes.
  • b N indicates Narrow; R, Regular; and W, Wide Series.
  • c The 0.734-inch and 1.469-inch outside diameter avoids washers which could be used in coin operated devices.
  • All dimensions are in inches.
  • Inside and outside diameters shall be concentric within at least the inside diameter tolerance.
  • Washers shall be flat within 0.005-inch for basic outside diameters up through 0.875-inch and within 0.010 inch for larger outside diameters.
  • For 21 ⁄ 4-, 21 ⁄ 2- , 23 ⁄ 4-, and 3-inch sizes see ASME B18.22.1-1965 (R1998).

ASME Material Specifications

ASTM A693 Washers
ASTM F436/F436M Washers
ASTM F959/959M Direct Tension Squirter DTI Washers
ASTM F2437/2437M Direct Tension Squirter DTI Washers
ASTM F844 Washers
ISO 898-3 Washers
ASTM A36 Washers
ASTM A240 Washers, Spacer, Flange
ASTM B96 Washers
ASTM B127 Washers
ASTM B162 Washers
ASTM B168 Washers
ASTM B171 Washers
ASTM B265 Washers
ASTM B409 Washers
ASTM B424 Washers
ASTM B551 Washers
ASTM B708 Washers

EN Material Specifications

ISO Material Specifications