Nut & Washer Size Chart
Nut & Washer Size Chart
Mutual Screw & Supply · mutualscrew.com · (800) 222-0324
Hex nut dimensions per ASME B18.2.2. Width across flats (WAF) is the wrench size. Width across corners (WAC) is the maximum envelope. All dimensions in inches.
| Bolt Size | TPI (UNC) | Width Across Flats | Width Across Corners | Nut Height | Heavy Hex WAF | Heavy Hex Height |
|---|---|---|---|---|---|---|
| Machine Screw Sizes | ||||||
| #4 | 40 | 5/16" | 0.364" | 7/64" | — | — |
| #6 | 32 | 5/16" | 0.364" | 7/64" | — | — |
| #8 | 32 | 11/32" | 0.404" | 1/8" | — | — |
| #10 | 24 | 3/8" | 0.433" | 1/8" | — | — |
| #12 | 24 | 7/16" | 0.505" | 5/32" | — | — |
| Fractional Sizes | ||||||
| 1/4" | 20 | 7/16" | 0.505" | 7/32" | — | — |
| 5/16" | 18 | 1/2" | 0.577" | 17/64" | — | — |
| 3/8" | 16 | 9/16" | 0.650" | 21/64" | — | — |
| 7/16" | 14 | 11/16" | 0.794" | 3/8" | — | — |
| 1/2" | 13 | 3/4" | 0.866" | 7/16" | 7/8" | 31/64" |
| 9/16" | 12 | 7/8" | 1.010" | 31/64" | 15/16" | 35/64" |
| 5/8" | 11 | 15/16" | 1.083" | 35/64" | 1-1/16" | 39/64" |
| 3/4" | 10 | 1-1/8" | 1.299" | 41/64" | 1-1/4" | 47/64" |
| 7/8" | 9 | 1-5/16" | 1.516" | 3/4" | 1-7/16" | 55/64" |
| 1" | 8 | 1-1/2" | 1.732" | 55/64" | 1-5/8" | 63/64" |
| 1-1/8" | 7 | 1-11/16" | 1.949" | 31/32" | 1-13/16" | 1-7/64" |
| 1-1/4" | 7 | 1-7/8" | 2.165" | 1-1/16" | 2" | 1-7/32" |
| 1-1/2" | 6 | 2-1/4" | 2.598" | 1-9/32" | 2-3/8" | 1-7/16" |
Jam nuts (ASME B18.2.2) are approximately half the height of a standard hex nut. Used as a locking device against a full nut, or in low-clearance applications. Same width across flats as a standard hex nut of the same diameter.
| Bolt Size | TPI (UNC) | Width Across Flats | Width Across Corners | Jam Nut Height | Std. Hex Height (ref.) |
|---|---|---|---|---|---|
| Machine Screw Sizes | |||||
| #4 | 40 | 5/16" | 0.364" | 3/64" | 7/64" |
| #6 | 32 | 5/16" | 0.364" | 3/64" | 7/64" |
| #8 | 32 | 11/32" | 0.404" | 1/16" | 1/8" |
| #10 | 24 | 3/8" | 0.433" | 5/64" | 1/8" |
| #12 | 24 | 7/16" | 0.505" | 5/64" | 5/32" |
| Fractional Sizes | |||||
| 1/4" | 20 | 7/16" | 0.505" | 5/32" | 7/32" |
| 5/16" | 18 | 1/2" | 0.577" | 3/16" | 17/64" |
| 3/8" | 16 | 9/16" | 0.650" | 7/32" | 21/64" |
| 7/16" | 14 | 11/16" | 0.794" | 1/4" | 3/8" |
| 1/2" | 13 | 3/4" | 0.866" | 5/16" | 7/16" |
| 9/16" | 12 | 7/8" | 1.010" | 5/16" | 31/64" |
| 5/8" | 11 | 15/16" | 1.083" | 11/32" | 35/64" |
| 3/4" | 10 | 1-1/8" | 1.299" | 13/32" | 41/64" |
| 7/8" | 9 | 1-5/16" | 1.516" | 29/64" | 3/4" |
| 1" | 8 | 1-1/2" | 1.732" | 1/2" | 55/64" |
| 1-1/8" | 7 | 1-11/16" | 1.949" | 9/16" | 31/32" |
| 1-1/4" | 7 | 1-7/8" | 2.165" | 5/8" | 1-1/16" |
| 1-1/2" | 6 | 2-1/4" | 2.598" | 3/4" | 1-9/32" |
SAE vs. USS washers: SAE washers (ASME B18.21.1) are narrower and thinner — used with machine screws and bolts in close-tolerance applications. USS washers are wider with a larger OD, better for distributing load in wood, soft materials, and rough applications. Both are specified by bolt size, not washer OD.
| Bolt Size | SAE ID | SAE OD | SAE Thickness | USS ID | USS OD | USS Thickness |
|---|---|---|---|---|---|---|
| Machine Screw Sizes | ||||||
| #6 | 0.138" | 3/8" | 0.049" | — | — | — |
| #8 | 0.164" | 7/16" | 0.049" | — | — | — |
| #10 | 0.190" | 1/2" | 0.049" | — | — | — |
| Fractional Sizes | ||||||
| 1/4" | 0.281" | 5/8" | 0.065" | 0.281" | 3/4" | 0.065" |
| 5/16" | 0.344" | 11/16" | 0.065" | 0.344" | 7/8" | 0.083" |
| 3/8" | 0.406" | 13/16" | 0.065" | 0.406" | 1" | 0.083" |
| 7/16" | 0.469" | 59/64" | 0.065" | 0.469" | 1-1/4" | 0.083" |
| 1/2" | 0.531" | 1-1/16" | 0.095" | 0.531" | 1-3/8" | 0.109" |
| 9/16" | 0.594" | 1-3/16" | 0.095" | 0.594" | 1-1/2" | 0.109" |
| 5/8" | 0.656" | 1-5/16" | 0.095" | 0.656" | 1-3/4" | 0.134" |
| 3/4" | 0.812" | 1-1/2" | 0.134" | 0.812" | 2" | 0.148" |
| 7/8" | 0.938" | 1-3/4" | 0.134" | 0.938" | 2-1/4" | 0.165" |
| 1" | 1.062" | 2" | 0.134" | 1.062" | 2-1/2" | 0.165" |
| 1-1/4" | 1.312" | 2-1/2" | 0.165" | 1.312" | 3" | 0.165" |
| 1-1/2" | 1.562" | 3" | 0.165" | 1.562" | 3-1/2" | 0.180" |
Split lock washers (helical spring) resist loosening by biting into both the nut and bearing surface. Internal tooth washers grip more evenly on small-diameter heads. External tooth washers provide maximum bite and are preferred on larger fasteners and sheet metal. All dimensions per ASME B18.21.1, in inches.
| Bolt Size | Split Lock ID | Split Lock OD | Split Lock Thickness | Int. Tooth OD | Ext. Tooth OD | Tooth Thickness |
|---|---|---|---|---|---|---|
| Machine Screw Sizes | ||||||
| #4 | 0.120" | 0.209" | 0.022" | 0.270" | 0.260" | 0.019" |
| #6 | 0.148" | 0.250" | 0.030" | 0.323" | 0.320" | 0.022" |
| #8 | 0.174" | 0.293" | 0.040" | 0.376" | 0.381" | 0.023" |
| #10 | 0.200" | 0.334" | 0.047" | 0.433" | 0.440" | 0.025" |
| #12 | 0.227" | 0.377" | 0.056" | 0.510" | 0.510" | 0.028" |
| Fractional Sizes | ||||||
| 1/4" | 0.255" | 0.489" | 0.062" | 0.510" | 0.510" | 0.028" |
| 5/16" | 0.318" | 0.586" | 0.078" | 0.610" | 0.610" | 0.034" |
| 3/8" | 0.382" | 0.683" | 0.094" | 0.694" | 0.694" | 0.040" |
| 7/16" | 0.446" | 0.779" | 0.109" | 0.760" | 0.760" | 0.040" |
| 1/2" | 0.509" | 0.873" | 0.125" | 0.900" | 0.900" | 0.045" |
| 9/16" | 0.572" | 0.971" | 0.141" | — | 1.010" | 0.045" |
| 5/8" | 0.636" | 1.079" | 0.156" | — | 1.100" | 0.050" |
| 3/4" | 0.763" | 1.271" | 0.188" | — | 1.320" | 0.055" |
| 7/8" | 0.890" | 1.464" | 0.219" | — | 1.540" | 0.060" |
| 1" | 1.017" | 1.661" | 0.250" | — | 1.740" | 0.067" |
Fender washers have an extra-large OD relative to their ID — significantly larger than USS washers. Originally designed for automotive sheet metal, they're used anywhere load must be distributed over a very wide area: drywall, foam, rubber gaskets, and soft or oversize holes. Per ASME B18.21.1.
| Bolt Size | Inner Diameter | Outer Diameter | Thickness | Typical Use |
|---|---|---|---|---|
| #6 | 0.148" | 1/2" | 0.040" | Light sheet metal, plastic panels |
| #8 | 0.174" | 1/2" | 0.040" | Light sheet metal, plastic panels |
| #10 | 0.200" | 1" | 0.050" | Thin sheet metal, automotive trim |
| 1/4" | 0.281" | 1-1/4" | 0.051" | General automotive, HVAC panels |
| 5/16" | 0.344" | 1-1/2" | 0.065" | Automotive bodywork, equipment panels |
| 3/8" | 0.406" | 1-3/4" | 0.065" | Structural attachment to thin material |
| 7/16" | 0.469" | 2" | 0.083" | Deck ledger, dock hardware |
| 1/2" | 0.531" | 2" | 0.095" | Most common fender washer size. General purpose. |
| 9/16" | 0.594" | 2-1/2" | 0.095" | Larger structural panels |
| 5/8" | 0.656" | 2-1/2" | 0.095" | Heavy-duty automotive, trailer hitches |
| 3/4" | 0.812" | 3" | 0.134" | Large structural, post bases |
| 1" | 1.062" | 3" | 0.134" | Post bases, anchor bolt plates |
Shop Nuts & Washers at Mutual Screw & Supply
We stock hex nuts, jam nuts, lock nuts, flat washers, lock washers, and fender washers in US and metric sizes across all grades and finishes. Family owned since 1947.
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Dimensions per ASME B18.2.2, B18.21.1, ISO 4032, ISO 4035, ISO 7089, ISO 7093, and DIN 127/6797. Verify with product datasheets for critical applications.