ASME B18.22.1Flat washer

ASME B18.22.1 3/8 Flat washer

ASME B18.22.1 3/8 is a flat washer, sized for 3/8 bolts. The inch-series plain washer in the preferred series. Inside diameters are sized to the nominal bolt diameter plus clearance, matching the inch bolt range rather than metric.

Dimensioned drawing — ASME B18.22.1 3/8d2 0.81⌀0.41h 0.07
ASME B18.22.1 3/8 — Flat washerNominal dimensions in inches · Not to scale
Thread3/8
Inside Ø d10.406 in
Outside Ø d20.812 in
Thickness h0.065 in

Dimensions

Type
Flat washer
Size
3/8
For bolt size
3/8
Total height h
0.065 in
Inside diameter d1
0.406 in
Outside diameter d2
0.812 in

Nominal values in inches as published in ASME B18.22.1. Estimated weight 3.247 g per piece in steel (3.268 g in stainless), calculated from the nominal geometry — real parts vary with tolerance and head chamfers.

Other lengthsASME B18.22.1 3/8

All 3/8 specifications

Choosing and fitting this size

ASME B18.22.1 3/8 is a washer with a 0.406 in inside diameter. It sits under a bolt head or nut to spread the clamping load; the inside diameter matches the bolt it is specified for, so the washer and fastener should always be ordered as a pair.

Hardness is the governing property rather than tensile strength: a washer specified for a Grade 8 bolt must be hard enough not to deform under preload, otherwise the joint loses clamping force quietly. Match the washer grade to the bolt grade rather than picking on inside diameter alone.