# Plain washers, inch Type B (narrow, regular, wide): #0 to 3 in ID, OD, thickness + 12 washer files

> What are the dimensions of a Type B narrow, regular or wide flat washer, and what is the OD of a 3/8 wide washer?

- Category: Hardware › Fasteners
- Kind: Standard part
- Basis: Tubing China's ANSI Type B flat washer table (#0 to 3 in), checked against Portland Bolt's Type B table (1/4 to 3 in, same ID, OD and thickness on every row read) and Fastener SuperStore's narrow-series limits; twelve washer files
- Page: https://xemstudio.com/objects/plain-washers-inch-type-b/ · JSON: https://xemstudio.com/api/geometry?object=plain-washers-inch-type-b · Plain text: https://xemstudio.com/objects/plain-washers-inch-type-b/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); files CC BY 4.0 or their publisher's license
- Use in every chat: add https://xemstudio.com/mcp as a connector (https://xemstudio.com/use-with-ai/)

## Overall (mm)

| length | width | height |
|---|---|---|
| 63.5 | 63.5 | 4.1 |

**Exact dimensions.** Every file is drawn at true size with no tolerance added. The holes and pins that meet another part are listed below under Mating features, with the fit each joint needs; open those by your process's clearance before making the part.

## Notes

- Type B plain washers come in three series for each screw size: narrow (N), regular (R) and wide (W), with a bore that is the same across the three. Dimensions are basic inches with computed mm columns. Basic ID, OD and thickness are the same in Tubing China's and Portland Bolt's tables for every size from 1/4 to 3 in. Fastener SuperStore's narrow-series table (labelled ASME B18.21.1-2009) prints limits that fit the same basics: 1/4 in ID 0.296 / 0.276 around 0.281, OD 0.515 / 0.495 around 0.500, thickness 0.071 / 0.056 around 0.063 (and the same pattern at 3/8, 1/2 in). Standard naming varies by source: Portland Bolt's page is titled 'Type B plain washers', Fastener SuperStore cites ASME B18.21.1-2009, and Engineers Edge's Type A table is credited to ANSI/ASME B18.22.1. Check the edition you buy to.
- Portland Bolt prints some obvious slips (a tolerance of 0.303 and a 1-in narrow maximum thickness of 0.122); basic values are used, not tolerances. The Portland Bolt table has the thickness header shifted by one column; its 'basic' thickness (0.063 for 1/4 narrow) is the one used. Portland Bolt's 7/8 and 1 in series rows and the extra half sizes were not all compared.
- Type A (SAE narrow / USS wide) washers, 1/4 to 3/4 in, are on flat-washers-inch. Type B is the series with a bore that is about 0.031 in over the screw for the same series, so the 1/4 in Type B wide washer (ID 0.281, OD 1.000) is not the 1/4 in USS Type A washer (ID 0.312, OD 0.734).
- Files are Xem-drawn flat annuli at the basic sizes for 1/4, 3/8, 1/2 and 3/4 in in all three series; thickness is the basic value. McMaster-Carr sells these washers with per-part STEP; no category URL could be verified, so none is linked.

## Mating features (exact size; open press / slide / run / socket by your process clearance, leave designed and clamp as drawn)

| feature | exact | mates with | fit | files |
|---|---|---|---|---|
| bore | 1/4 in 0.281 (7.14 mm), 3/8 in 0.406 (10.31), 1/2 in 0.531 (13.49), 3/4 in 0.812 (20.62) | bolt of the nominal size; plain cylinder at the major diameter | designed | washer-type-b-* |
| outside | N/R/W: 1/4 in 0.500 / 0.734 / 1.000, 3/8 in 0.734 / 1.000 / 1.250, 1/2 in 1.000 / 1.250 / 1.750, 3/4 in 1.375 / 2.000 / 2.500 in | round counterbore that seats the washer: Ø = OD + your process clearance | slide | washer-type-b-* |

## Sizes

| screw size | decimal size (in) | series | ID (in) | OD (in) | thickness (in) | ID (mm) | OD (mm) | thickness (mm) |
|---|---|---|---|---|---|---|---|---|
| #0 | 0.06 | narrow | 0.068 | 0.125 | 0.025 | 1.73 | 3.17 | 0.64 |
| #0 | 0.06 | regular | 0.068 | 0.188 | 0.025 | 1.73 | 4.78 | 0.64 |
| #0 | 0.06 | wide | 0.068 | 0.250 | 0.025 | 1.73 | 6.35 | 0.64 |
| #1 | 0.073 | narrow | 0.084 | 0.156 | 0.025 | 2.13 | 3.96 | 0.64 |
| #1 | 0.073 | regular | 0.084 | 0.219 | 0.025 | 2.13 | 5.56 | 0.64 |
| #1 | 0.073 | wide | 0.084 | 0.281 | 0.032 | 2.13 | 7.14 | 0.81 |
| #2 | 0.086 | narrow | 0.094 | 0.188 | 0.025 | 2.39 | 4.78 | 0.64 |
| #2 | 0.086 | regular | 0.094 | 0.250 | 0.032 | 2.39 | 6.35 | 0.81 |
| #2 | 0.086 | wide | 0.094 | 0.344 | 0.032 | 2.39 | 8.74 | 0.81 |
| #3 | 0.099 | narrow | 0.109 | 0.219 | 0.025 | 2.77 | 5.56 | 0.64 |
| #3 | 0.099 | regular | 0.109 | 0.312 | 0.032 | 2.77 | 7.92 | 0.81 |
| #3 | 0.099 | wide | 0.109 | 0.406 | 0.040 | 2.77 | 10.31 | 1.02 |
| #4 | 0.112 | narrow | 0.125 | 0.250 | 0.032 | 3.17 | 6.35 | 0.81 |
| #4 | 0.112 | regular | 0.125 | 0.375 | 0.040 | 3.17 | 9.52 | 1.02 |
| #4 | 0.112 | wide | 0.125 | 0.438 | 0.040 | 3.17 | 11.13 | 1.02 |
| #5 | 0.125 | narrow | 0.141 | 0.281 | 0.032 | 3.58 | 7.14 | 0.81 |
| #5 | 0.125 | regular | 0.141 | 0.406 | 0.040 | 3.58 | 10.31 | 1.02 |
| #5 | 0.125 | wide | 0.141 | 0.500 | 0.040 | 3.58 | 12.70 | 1.02 |
| #6 | 0.138 | narrow | 0.156 | 0.312 | 0.032 | 3.96 | 7.92 | 0.81 |
| #6 | 0.138 | regular | 0.156 | 0.438 | 0.040 | 3.96 | 11.13 | 1.02 |
| #6 | 0.138 | wide | 0.156 | 0.562 | 0.040 | 3.96 | 14.27 | 1.02 |
| #8 | 0.164 | narrow | 0.188 | 0.375 | 0.040 | 4.78 | 9.52 | 1.02 |
| #8 | 0.164 | regular | 0.188 | 0.500 | 0.040 | 4.78 | 12.70 | 1.02 |
| #8 | 0.164 | wide | 0.188 | 0.625 | 0.063 | 4.78 | 15.88 | 1.60 |
| #10 | 0.19 | narrow | 0.203 | 0.406 | 0.040 | 5.16 | 10.31 | 1.02 |
| #10 | 0.19 | regular | 0.203 | 0.562 | 0.040 | 5.16 | 14.27 | 1.02 |
| #10 | 0.19 | wide | 0.203 | 0.734 | 0.063 | 5.16 | 18.64 | 1.60 |
| #12 | 0.216 | narrow | 0.234 | 0.438 | 0.040 | 5.94 | 11.13 | 1.02 |
| #12 | 0.216 | regular | 0.234 | 0.625 | 0.063 | 5.94 | 15.88 | 1.60 |
| #12 | 0.216 | wide | 0.234 | 0.875 | 0.063 | 5.94 | 22.22 | 1.60 |
| 1/4 | 0.25 | narrow | 0.281 | 0.500 | 0.063 | 7.14 | 12.70 | 1.60 |
| 1/4 | 0.25 | regular | 0.281 | 0.734 | 0.063 | 7.14 | 18.64 | 1.60 |
| 1/4 | 0.25 | wide | 0.281 | 1.000 | 0.063 | 7.14 | 25.40 | 1.60 |
| 5/16 | 0.3125 | narrow | 0.344 | 0.625 | 0.063 | 8.74 | 15.88 | 1.60 |
| 5/16 | 0.3125 | regular | 0.344 | 0.875 | 0.063 | 8.74 | 22.22 | 1.60 |
| 5/16 | 0.3125 | wide | 0.344 | 1.125 | 0.063 | 8.74 | 28.57 | 1.60 |
| 3/8 | 0.375 | narrow | 0.406 | 0.734 | 0.063 | 10.31 | 18.64 | 1.60 |
| 3/8 | 0.375 | regular | 0.406 | 1.000 | 0.063 | 10.31 | 25.40 | 1.60 |
| 3/8 | 0.375 | wide | 0.406 | 1.250 | 0.100 | 10.31 | 31.75 | 2.54 |
| 7/16 | 0.4375 | narrow | 0.469 | 0.875 | 0.063 | 11.91 | 22.22 | 1.60 |
| 7/16 | 0.4375 | regular | 0.469 | 1.125 | 0.063 | 11.91 | 28.57 | 1.60 |
| 7/16 | 0.4375 | wide | 0.469 | 1.469 | 0.100 | 11.91 | 37.31 | 2.54 |
| 1/2 | 0.5 | narrow | 0.531 | 1.000 | 0.063 | 13.49 | 25.40 | 1.60 |
| 1/2 | 0.5 | regular | 0.531 | 1.250 | 0.100 | 13.49 | 31.75 | 2.54 |
| 1/2 | 0.5 | wide | 0.531 | 1.750 | 0.100 | 13.49 | 44.45 | 2.54 |
| 9/16 | 0.5625 | narrow | 0.594 | 1.125 | 0.063 | 15.09 | 28.57 | 1.60 |
| 9/16 | 0.5625 | regular | 0.594 | 1.469 | 0.100 | 15.09 | 37.31 | 2.54 |
| 9/16 | 0.5625 | wide | 0.594 | 2.000 | 0.100 | 15.09 | 50.80 | 2.54 |
| 5/8 | 0.625 | narrow | 0.656 | 1.250 | 0.100 | 16.66 | 31.75 | 2.54 |
| 5/8 | 0.625 | regular | 0.656 | 1.750 | 0.100 | 16.66 | 44.45 | 2.54 |
| 5/8 | 0.625 | wide | 0.656 | 2.250 | 0.160 | 16.66 | 57.15 | 4.06 |
| 3/4 | 0.75 | narrow | 0.812 | 1.375 | 0.100 | 20.62 | 34.92 | 2.54 |
| 3/4 | 0.75 | regular | 0.812 | 2.000 | 0.100 | 20.62 | 50.80 | 2.54 |
| 3/4 | 0.75 | wide | 0.812 | 2.500 | 0.160 | 20.62 | 63.50 | 4.06 |
| 7/8 | 0.875 | narrow | 0.938 | 1.469 | 0.100 | 23.83 | 37.31 | 2.54 |
| 7/8 | 0.875 | regular | 0.938 | 2.250 | 0.160 | 23.83 | 57.15 | 4.06 |
| 7/8 | 0.875 | wide | 0.938 | 2.750 | 0.160 | 23.83 | 69.85 | 4.06 |
| 1 | 1 | narrow | 1.062 | 1.750 | 0.100 | 26.97 | 44.45 | 2.54 |
| 1 | 1 | regular | 1.062 | 2.500 | 0.160 | 26.97 | 63.50 | 4.06 |
| 1 | 1 | wide | 1.062 | 3.000 | 0.160 | 26.97 | 76.20 | 4.06 |
| 1-1/8 | 1.125 | narrow | 1.188 | 2.000 | 0.100 | 30.18 | 50.80 | 2.54 |
| 1-1/8 | 1.125 | regular | 1.188 | 2.750 | 0.160 | 30.18 | 69.85 | 4.06 |
| 1-1/8 | 1.125 | wide | 1.188 | 3.250 | 0.160 | 30.18 | 82.55 | 4.06 |
| 1-1/4 | 1.25 | narrow | 1.312 | 2.250 | 0.160 | 33.32 | 57.15 | 4.06 |
| 1-1/4 | 1.25 | regular | 1.312 | 3.000 | 0.160 | 33.32 | 76.20 | 4.06 |
| 1-1/4 | 1.25 | wide | 1.312 | 3.500 | 0.250 | 33.32 | 88.90 | 6.35 |
| 1-1/2 | 1.5 | narrow | 1.562 | 2.750 | 0.160 | 39.67 | 69.85 | 4.06 |
| 1-1/2 | 1.5 | regular | 1.562 | 3.500 | 0.250 | 39.67 | 88.90 | 6.35 |
| 1-1/2 | 1.5 | wide | 1.562 | 4.000 | 0.250 | 39.67 | 101.60 | 6.35 |
| 2 | 2 | narrow | 2.125 | 3.750 | 0.250 | 53.97 | 95.25 | 6.35 |
| 2 | 2 | regular | 2.125 | 4.500 | 0.250 | 53.97 | 114.30 | 6.35 |
| 2 | 2 | wide | 2.125 | 5.000 | 0.250 | 53.97 | 127.00 | 6.35 |
| 3 | 3 | narrow | 3.125 | 5.500 | 0.375 | 79.38 | 139.70 | 9.52 |
| 3 | 3 | regular | 3.125 | 6.500 | 0.375 | 79.38 | 165.10 | 9.52 |
| 3 | 3 | wide | 3.125 | 7.000 | 0.375 | 79.38 | 177.80 | 9.52 |

## Where the files are

- Tubing China: [Standard ANSI Type B flat washer sizes: No. 0 to 3 in, N / R / W series, ID, OD, thickness](https://tubingchina.com/Standard-ANSI-Type-B-Flat-Washer-Sizes.htm) — web — Distributor table; numbers only
- Portland Bolt: [Dimensions of Type B plain washers: narrow / regular / wide, 1/4 to 3 in (ID, OD, thickness basic / max / min)](https://www.portlandbolt.com/print/?table=9931) — web — Distributor table; numbers only
- Fastener SuperStore: [Type B plain washers, narrow series (ASME B18.21.1-2009): ID, OD, thickness max / min](https://www.fastenersuperstore.com/product_specs/washers-flat-type-b-narrow) — web — Distributor table; numbers only

## Free STEP/STL (12 parts, CC BY 4.0, Xem Studio)

Index: https://xemstudio.com/files/hardware/plain-washers-inch-type-b/index.json

- washer-type-b-1-4-narrow: [STEP](https://xemstudio.com/files/hardware/plain-washers-inch-type-b/washer-type-b-1-4-narrow.step) · [STL](https://xemstudio.com/files/hardware/plain-washers-inch-type-b/washer-type-b-1-4-narrow.stl) — 1/4 in Type B plain washer, narrow series: ID 0.281 in (7.14 mm), OD 0.500 in (12.70 mm), thickness 0.063 in (1.60 mm), basic sizes; flat annulus, no tolerances
- washer-type-b-1-4-regular: [STEP](https://xemstudio.com/files/hardware/plain-washers-inch-type-b/washer-type-b-1-4-regular.step) · [STL](https://xemstudio.com/files/hardware/plain-washers-inch-type-b/washer-type-b-1-4-regular.stl) — 1/4 in Type B plain washer, regular series: ID 0.281 in (7.14 mm), OD 0.734 in (18.64 mm), thickness 0.063 in (1.60 mm), basic sizes; flat annulus, no tolerances
- washer-type-b-1-4-wide: [STEP](https://xemstudio.com/files/hardware/plain-washers-inch-type-b/washer-type-b-1-4-wide.step) · [STL](https://xemstudio.com/files/hardware/plain-washers-inch-type-b/washer-type-b-1-4-wide.stl) — 1/4 in Type B plain washer, wide series: ID 0.281 in (7.14 mm), OD 1.000 in (25.40 mm), thickness 0.063 in (1.60 mm), basic sizes; flat annulus, no tolerances
- washer-type-b-3-8-narrow: [STEP](https://xemstudio.com/files/hardware/plain-washers-inch-type-b/washer-type-b-3-8-narrow.step) · [STL](https://xemstudio.com/files/hardware/plain-washers-inch-type-b/washer-type-b-3-8-narrow.stl) — 3/8 in Type B plain washer, narrow series: ID 0.406 in (10.31 mm), OD 0.734 in (18.64 mm), thickness 0.063 in (1.60 mm), basic sizes; flat annulus, no tolerances
- washer-type-b-3-8-regular: [STEP](https://xemstudio.com/files/hardware/plain-washers-inch-type-b/washer-type-b-3-8-regular.step) · [STL](https://xemstudio.com/files/hardware/plain-washers-inch-type-b/washer-type-b-3-8-regular.stl) — 3/8 in Type B plain washer, regular series: ID 0.406 in (10.31 mm), OD 1.000 in (25.40 mm), thickness 0.063 in (1.60 mm), basic sizes; flat annulus, no tolerances
- washer-type-b-3-8-wide: [STEP](https://xemstudio.com/files/hardware/plain-washers-inch-type-b/washer-type-b-3-8-wide.step) · [STL](https://xemstudio.com/files/hardware/plain-washers-inch-type-b/washer-type-b-3-8-wide.stl) — 3/8 in Type B plain washer, wide series: ID 0.406 in (10.31 mm), OD 1.250 in (31.75 mm), thickness 0.100 in (2.54 mm), basic sizes; flat annulus, no tolerances
- washer-type-b-1-2-narrow: [STEP](https://xemstudio.com/files/hardware/plain-washers-inch-type-b/washer-type-b-1-2-narrow.step) · [STL](https://xemstudio.com/files/hardware/plain-washers-inch-type-b/washer-type-b-1-2-narrow.stl) — 1/2 in Type B plain washer, narrow series: ID 0.531 in (13.49 mm), OD 1.000 in (25.40 mm), thickness 0.063 in (1.60 mm), basic sizes; flat annulus, no tolerances
- washer-type-b-1-2-regular: [STEP](https://xemstudio.com/files/hardware/plain-washers-inch-type-b/washer-type-b-1-2-regular.step) · [STL](https://xemstudio.com/files/hardware/plain-washers-inch-type-b/washer-type-b-1-2-regular.stl) — 1/2 in Type B plain washer, regular series: ID 0.531 in (13.49 mm), OD 1.250 in (31.75 mm), thickness 0.100 in (2.54 mm), basic sizes; flat annulus, no tolerances
- washer-type-b-1-2-wide: [STEP](https://xemstudio.com/files/hardware/plain-washers-inch-type-b/washer-type-b-1-2-wide.step) · [STL](https://xemstudio.com/files/hardware/plain-washers-inch-type-b/washer-type-b-1-2-wide.stl) — 1/2 in Type B plain washer, wide series: ID 0.531 in (13.49 mm), OD 1.750 in (44.45 mm), thickness 0.100 in (2.54 mm), basic sizes; flat annulus, no tolerances
- washer-type-b-3-4-narrow: [STEP](https://xemstudio.com/files/hardware/plain-washers-inch-type-b/washer-type-b-3-4-narrow.step) · [STL](https://xemstudio.com/files/hardware/plain-washers-inch-type-b/washer-type-b-3-4-narrow.stl) — 3/4 in Type B plain washer, narrow series: ID 0.812 in (20.62 mm), OD 1.375 in (34.92 mm), thickness 0.100 in (2.54 mm), basic sizes; flat annulus, no tolerances
- washer-type-b-3-4-regular: [STEP](https://xemstudio.com/files/hardware/plain-washers-inch-type-b/washer-type-b-3-4-regular.step) · [STL](https://xemstudio.com/files/hardware/plain-washers-inch-type-b/washer-type-b-3-4-regular.stl) — 3/4 in Type B plain washer, regular series: ID 0.812 in (20.62 mm), OD 2.000 in (50.80 mm), thickness 0.100 in (2.54 mm), basic sizes; flat annulus, no tolerances
- washer-type-b-3-4-wide: [STEP](https://xemstudio.com/files/hardware/plain-washers-inch-type-b/washer-type-b-3-4-wide.step) · [STL](https://xemstudio.com/files/hardware/plain-washers-inch-type-b/washer-type-b-3-4-wide.stl) — 3/4 in Type B plain washer, wide series: ID 0.812 in (20.62 mm), OD 2.500 in (63.50 mm), thickness 0.160 in (4.06 mm), basic sizes; flat annulus, no tolerances

## Questions

**What is the OD of a 3/8 wide Type B washer?**

1.250 in (31.75 mm) with 0.406 in bore and 0.100 in thickness (Tubing China and Portland Bolt agree).

**What is the difference between narrow, regular and wide washers?**

Bore is the same; outside diameter grows: 1/4 in is 0.500, 0.734 and 1.000 in, with thickness 0.063 in in all three.

## Fits with

- [Flat washers, inch: SAE and USS, 1/4 to 3/4 in (ASME B18.21.1 Type A)](https://xemstudio.com/objects/flat-washers-inch/)
- [Flat washers, M2–M8 (ISO 7089)](https://xemstudio.com/objects/flat-washers-metric/)
- [Hex nuts, inch: #4-40 to 3/4-10 (ASME B18.2.2)](https://xemstudio.com/objects/hex-nuts-inch/)
- [Hex bolts, inch: 1/4-20 to 3/4-10 (ASME B18.2.1)](https://xemstudio.com/objects/hex-bolts-inch/)
- [Large (fender) washers, DIN 9021 / ISO 7093: M2.5–M36 bore, outside diameter, thickness + nylon variant + 8 washer files](https://xemstudio.com/objects/large-washers-din-9021-iso-7093/)