Standard ANSI Type B Flat Washer Sizes
Stamped metal washers measure typically 0.005 to 0.250 in. thick, with outside diameters to 5 in. Metalforming companies stamp them on presses from 5 to 200 tons from sheetmetal blanks fed manually or automatically, or often from coil stock on progressive dies. Press lines may include automatic uncoiling, feeding and injection systems.
Washers can be stamped from any punchable materials, including spring steel, carbon steel, stainless steel, brass and aluminum alloys. Washer designs include wavy, bowed and slotted. Typical styles include fender washers (light, medium and heavy), high-strength structural washers, U-bolt washers, split-lock styles, dock washers and automotive body shims. Order quantities typically start at 100 pieces, although many suppliers will satisfy special requests for smaller quantities.
Value-added services offered by washer manufacturers include flat or tumble deburring, heat treating and plating (cadmium, phosphate, mechanical galvanizing and hot-dip galvanizing). Some washer manufacturers also offer fully-equipped A2LA laboratories and meet quality standards for nuclear construction, MIL-Spec work, and SAE and ANSI specs.
Two types of flat washers are defined for general use. Type A is a series of steel washers with broad tolerances, where design refinement is not important. They range from No. 6 to 3-in. hole size and from 3/16 to 5½-in. OD. Type A washers are satisfactory for most assemblies. Type B washers are of higher quality and are specified in Narrow, Regular, and Wide diameters for each screw size from No. 0 to 3 in. However, many other standard sizes are available.
Series Designations -- N-Narrow, R-Regular, W-Wide
American National Standard (ANSI)
Type B Plain Washers |
Nominal
Size |
Decimal
Equiv. Size |
Series |
Inside
Diameter |
Outside
Diameter |
Thickness |
| No. 0 |
0.060" |
N |
0.0680 |
0.1250 |
0.0250 |
| R |
0.0680 |
0.1880 |
0.0250 |
| W |
0.0680 |
0.2500 |
0.0250 |
| No. 1 |
0.073" |
N |
0.0840 |
0.1560 |
0.0250 |
| R |
0.0840 |
0.2190 |
0.0250 |
| W |
0.0840 |
0.2810 |
0.0320 |
| No. 2 |
0.086" |
N |
0.0940 |
0.1880 |
0.0250 |
| R |
0.0940 |
0.2500 |
0.0320 |
| W |
0.0940 |
0.3440 |
0.0320 |
| No. 3 |
0.099" |
N |
0.1090 |
0.2190 |
0.0250 |
| R |
0.1090 |
0.3120 |
0.0320 |
| W |
0.1090 |
0.4060 |
0.0400 |
| No. 4 |
0.112" |
N |
0.1250 |
0.2500 |
0.0320 |
| R |
0.1250 |
0.3750 |
0.0400 |
| W |
0.1250 |
0.4380 |
0.0400 |
| No. 5 |
0.125" |
N |
0.1410 |
0.2810 |
0.0320 |
| R |
0.1410 |
0.4060 |
0.0400 |
| W |
0.1410 |
0.5000 |
0.0400 |
| No. 6 |
0.138" |
N |
0.1560 |
0.3120 |
0.0320 |
| R |
0.1560 |
0.4380 |
0.0400 |
| W |
0.1560 |
0.5620 |
0.0400 |
Nominal
Size |
Decimal
Equiv. Size |
Series |
Inside
Diameter |
Outside
Diameter |
Thickness |
| No. 8 |
0.164" |
N |
0.1880 |
0.3750 |
0.0400 |
| R |
0.1880 |
0.5000 |
0.0400 |
| W |
0.1880 |
0.6250 |
0.0630 |
| No. 10 |
0.190" |
N |
0.2030 |
0.4060 |
0.0400 |
| R |
0.2030 |
0.5620 |
0.0400 |
| W |
0.2030 |
0.7340 |
0.0630 |
| No. 12 |
0.216" |
N |
0.2340 |
0.4380 |
0.0400 |
| R |
0.2340 |
0.6250 |
0.0630 |
| W |
0.2340 |
0.8750 |
0.0630 |
| .25 |
0.25" |
N |
0.2810 |
0.5000 |
0.0630 |
| R |
0.2810 |
0.7340 |
0.0630 |
| W |
0.2810 |
1.0000 |
0.0630 |
| .3125 |
0.312" |
N |
0.3440 |
0.6250 |
0.0630 |
| R |
0.3440 |
0.8750 |
0.0630 |
| W |
0.3440 |
1.1250 |
0.0630 |
| .375 |
0.375" |
N |
0.4060 |
0.7340 |
0.0630 |
| R |
0.4060 |
1.0000 |
0.0630 |
| W |
0.4060 |
1.2500 |
0.1000 |
| .4375 |
0.438" |
N |
0.4690 |
0.8750 |
0.0630 |
| R |
0.4690 |
1.1250 |
0.0630 |
| W |
0.4690 |
1.4690 |
0.1000 |
Nominal
Size |
Decimal
Equiv. Size |
Series |
Inside
Diameter |
Outside
Diameter |
Thickness |
| .5 |
0.500" |
N |
0.5310 |
1.0000 |
0.0630 |
| R |
0.5310 |
1.2500 |
0.1000 |
| W |
0.5310 |
1.7500 |
0.1000 |
| .5625 |
0.562" |
N |
0.5940 |
1.1250 |
0.0630 |
| R |
0.5940 |
1.4690 |
0.1000 |
| W |
0.5940 |
2.0000 |
0.1000 |
| .625 |
0.625" |
N |
0.6560 |
1.2500 |
0.1000 |
| R |
0.6560 |
1.7500 |
0.1000 |
| W |
0.6560 |
2.2500 |
0.1600 |
| .75 |
0.750" |
N |
0.8120 |
1.3750 |
0.1000 |
| R |
0.8120 |
2.0000 |
0.1000 |
| W |
0.8120 |
2.5000 |
0.1600 |
| .875 |
0.875" |
N |
0.9380 |
1.4690 |
0.1000 |
| R |
0.9380 |
2.2500 |
0.1600 |
| W |
0.9380 |
2.7500 |
0.1600 |
| 1 |
1.000" |
N |
1.0620 |
1.7500 |
0.1000 |
| R |
1.0620 |
2.5000 |
0.1600 |
| W |
1.0620 |
3.0000 |
0.1600 |
| 1.125 |
1.125" |
N |
1.1880 |
2.0000 |
0.1000 |
| R |
1.1880 |
2.7500 |
0.1600 |
| W |
1.1880 |
3.2500 |
0.1600 |
Nominal
Size |
Decimal
Equiv. Size |
Series |
Inside
Diameter |
Outside
Diameter |
Thickness |
| 1.25 |
1.250" |
N |
1.3120 |
2.2500 |
0.1600 |
| R |
1.3120 |
3.0000 |
0.1600 |
| W |
1.3120 |
3.5000 |
0.2500 |
| 1.375 |
1.375" |
N |
1.4380 |
2.5000 |
0.1600 |
| R |
1.4380 |
3.2500 |
0.1600 |
| W |
1.4380 |
3.7500 |
0.2500 |
| 1.5 |
1.500" |
N |
1.5620 |
2.7500 |
0.1600 |
| R |
1.5620 |
3.5000 |
0.2500 |
| W |
1.5620 |
4.0000 |
0.2500 |
| 1.625 |
1.625" |
N |
1.7500 |
3.0000 |
0.1600 |
| R |
1.7500 |
3.7500 |
0.2500 |
| W |
1.7500 |
4.2500 |
0.2500 |
| 1.75 |
1.750" |
N |
1.8750 |
3.2500 |
0.1600 |
| R |
1.8750 |
4.0000 |
0.2500 |
| W |
1.8750 |
4.5000 |
0.2500 |
| 1.875 |
1.875" |
N |
2.0000 |
3.5000 |
0.2500 |
| R |
2.0000 |
4.2500 |
0.2500 |
| W |
2.0000 |
4.7500 |
0.2500 |
| 2 |
2.000" |
N |
2.1250 |
3.7500 |
0.2500 |
| R |
2.1250 |
4.5000 |
0.2500 |
| W |
2.1250 |
5.0000 |
0.2500 |
Nominal
Size |
Decimal
Equiv. Size |
Series |
Inside
Diameter |
Outside
Diameter |
Thickness |
| 2.25 |
2.250" |
N |
2.3750 |
4.0000 |
0.2500 |
| R |
2.3750 |
5.0000 |
0.2500 |
| W |
2.3750 |
5.5000 |
0.3750 |
| 2.5 |
2.500" |
N |
2.6250 |
4.5000 |
0.2500 |
| R |
2.6250 |
5.5000 |
0.3750 |
| W |
2.6250 |
6.0000 |
0.3750 |
| 2.75 |
2.750" |
N |
2.8750 |
5.0000 |
0.2500 |
| R |
2.8750 |
6.0000 |
0.3750 |
| W |
2.8750 |
6.5000 |
0.3750 |
| 3 |
3.000" |
N |
3.1250 |
5.5000 |
0.3750 |
| R |
3.1250 |
6.5000 |
0.3750 |
W |
3.1250 |
7.0000 |
0.3750 |
N-Narrow, R-Regular, W-Wide
Related References:
Screw Thread Limits Table
UNC UNF Threads Per Inch TPI Threads Per Inch
Wood Screw Pilot Hole Sizes Table
Standard NPT National Pipe Thread Tap Drill Sizes Table
ASTM ISO Metric Thread Sizes and Tap Drill Table
Metric Thread Size Tap Drill Table
Standard Tap Drills Clearance Holes Table
Standard Drill Sizes Decimal Equivalents Table
Socket Head Cap Screw Sizes Dimension Table
SAE Grade ASTM Bolt Identify Marks Mechanical Properties
Steel Bolt Torque Specifications Table
Finished Hex Nut Dimensions
Heavy Hex Nut Dimensions Table
Standard ANSI Type B Flat Washer Sizes
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