ASME B18.21.1 Type B Plain Washers — Inch Series, Narrow / Regular / Wide (No.0 – 2 in)

ASME B18.21.1 Type B plain washer dimensions for inch-series bolts — inside diameter, outside diameter and thickness with plus/minus tolerances per nominal size in narrow, regular and wide series, from No.0 up to 2 in, transcribed row-for-row from the live-collected chart.

Last updated: 2026-11

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ASME B18.21.1 Type B Plain Washers — Inch Series, Narrow / Regular / Wide (No.0 – 2 in) in an industrial setting — Illustrative image redrawn from real product references — not a photograph of stocked items.

Specifications

Type B is the second plain-washer table of ASME B18.21.1: like Type A it is a flat annulus that distributes bolt load, but its per-size chart runs its own dimension set across the full three-series spread — narrow, regular and wide on every size from No.0 up to 2 in, 84 printed rows in all. Where Type A tabulates most small sizes in a single series and splits narrow/wide only on the larger ones, the Type B chart gives all three series per size, so the series decision (bearing area versus clearance and weight) is available from the smallest screw sizes up. Reading a row, a regular-series washer for a 1/4 in bolt: inside diameter basic 0.281 in (+0.015/−0.005), outside diameter 1.000 in, thickness 0.063 in (+0.071/−0.056 limits as printed) — while the narrow series of the same size runs OD 0.500 in — and note the regular series OD of 0.734 in is the anti-coin dimension the source flags with its Note 2 marker. Tolerances are asymmetric plus/minus because washers are stamped; the limits are what receiving inspection checks. The collected table covers nominal washer sizes No.0 through 2 in; hardness, finish and material are not tabulated — per RFQ. Type A dimensions live on the sibling Type A page in this catalog.

Standard	ASME B18.21.1 — plain washers, inch series; Type B chart, narrow / regular / wide series on every nominal size
Size range	Nominal washer sizes No.0 – 2 in, 84 printed rows (28 sizes × 3 series)
Tabulated dimensions (in)	Per row: inside diameter, outside diameter, thickness — each basic with plus/minus tolerance; example regular 1/4 in: ID 0.281 +0.015/−0.005, OD 1.000, thickness 0.063
Anti-coin note	Selected outside diameters carry the source's Note 2 marker (0.734 and 1.469 in ODs avoid washers usable in coin-operated devices) — printed inline on the table and footnoted
Hardness / finish / material	Not tabulated by the collected chart — per RFQ (state material, hardness range and finish together)

ASME B18.21.1 Type B plain washers (inch series) — per-size dimensions, narrow / regular / wide seriesAll dimensions in inches. A = inside diameter, B = outside diameter, C = thickness, each basic with plus/minus tolerance; every nominal size is tabulated in three series (N = narrow, R = regular, W = wide — the same bolt size takes all three; series choice is an ordering decision). Source Note 1: nominal washer sizes are intended for use with comparable nominal screw or bolt sizes. The source prints the anti-coin outside diameters with their note marker inline ("0.734Note 2", "0.734Note2", "1.469Note2" — Note 2: the 0.734/1.469 in outside diameters avoid washers usable in coin-operated devices; the marker spacing itself varies row to row in the source) — read the numeric value and see the flagged footnotes.
Nominal Washer Size	Nominal Bolt Dia. (basic)	Series (N narrow / R regular / W wide)	A — Inside Dia. (basic)	A (plus)	A (minus)	B — Outside Dia. (basic)	B (plus)	B (minus)	C — Thickness (basic)	C (plus)	C (minus)
No.0	0.060	N	0.068	0.000	0.005	0.125	0.000	0.005	0.025	0.028	0.022
No.0	0.060	R	0.068	0.000	0.005	0.188	0.000	0.005	0.025	0.028	0.022
No.0	0.060	W	0.068	0.000	0.005	0.250	0.000	0.005	0.025	0.028	0.022
No.1	0.073	N	0.084	0.000	0.005	0.156	0.000	0.005	0.025	0.028	0.022
No.1	0.073	R	0.084	0.000	0.005	0.219	0.000	0.005	0.025	0.028	0.022
No.1	0.073	W	0.084	0.000	0.005	0.281	0.000	0.005	0.032	0.036	0.028
No.2	0.086	N	0.094	0.000	0.005	0.188	0.000	0.005	0.025	0.028	0.022
No.2	0.086	R	0.094	0.000	0.005	0.250	0.000	0.005	0.032	0.036	0.028
No.2	0.086	W	0.094	0.000	0.005	0.344	0.000	0.005	0.032	0.036	0.028
No.3	0.099	N	0.109	0.000	0.005	0.219	0.000	0.005	0.025	0.028	0.022
No.3	0.099	R	0.109	0.000	0.005	0.312	0.000	0.005	0.032	0.036	0.028
No.3	0.099	W	0.109	0.008	0.005	0.406	0.008	0.005	0.040	0.045	0.036
No.4	0.112	N	0.125	0.000	0.005	0.250	0.000	0.005	0.032	0.036	0.028
No.4	0.112	R	0.125	0.008	0.005	0.375	0.008	0.005	0.040	0.045	0.036
No.4	0.112	W	0.125	0.008	0.005	0.438	0.008	0.005	0.040	0.045	0.036
No.5	0.125	N	0.141	0.000	0.005	0.281	0.000	0.005	0.032	0.036	0.028
No.5	0.125	R	0.141	0.008	0.005	0.406	0.008	0.005	0.040	0.045	0.036
No.5	0.125	W	0.141	0.008	0.005	0.500	0.008	0.005	0.040	0.045	0.036
No.6	0.138	N	0.156	0.000	0.005	0.312	0.000	0.005	0.032	0.036	0.028
No.6	0.138	R	0.156	0.008	0.005	0.438	0.008	0.005	0.040	0.045	0.036
No.6	0.138	W	0.156	0.008	0.005	0.562	0.008	0.005	0.040	0.045	0.036
No.8	0.164	N	0.188	0.008	0.005	0.375	0.008	0.005	0.040	0.045	0.036
No.8	0.164	R	0.188	0.008	0.005	0.500	0.008	0.005	0.040	0.045	0.036
No.8	0.164	W	0.188	0.008	0.005	0.625	0.015	0.005	0.063	0.071	0.056
No.10	0.190	N	0.203	0.008	0.005	0.406	0.008	0.005	0.040	0.045	0.036
No.10	0.190	R	0.203	0.008	0.005	0.562	0.008	0.005	0.040	0.045	0.036
No.10	0.190	W	0.203	0.008	0.005	0.734	0.015	0.007	0.063	0.071	0.056
No.12	0.216	N	0.234	0.008	0.005	0.438	0.008	0.005	0.040	0.045	0.036
No.12	0.216	R	0.234	0.008	0.005	0.625	0.015	0.005	0.063	0.071	0.056
No.12	0.216	W	0.234	0.008	0.005	0.875	0.015	0.007	0.063	0.071	0.056
1/4	0.250	N	0.281	0.015	0.005	0.500	0.015	0.005	0.063	0.071	0.056
1/4	0.250	R	0.281	0.015	0.005	0.734	0.015	0.007	0.063	0.071	0.056
1/4	0.250	W	0.281	0.015	0.005	1.000	0.015	0.007	0.063	0.071	0.056
5/16	0.312	N	0.344	0.015	0.005	0.625	0.015	0.005	0.063	0.071	0.056
5/16	0.312	R	0.344	0.015	0.005	0.875	0.015	0.007	0.063	0.071	0.056
5/16	0.312	W	0.344	0.015	0.005	1.125	0.015	0.007	0.063	0.071	0.056
3/8	0.375	N	0.406	0.015	0.005	0.734	0.015	0.007	0.063	0.071	0.056
3/8	0.375	R	0.406	0.015	0.005	1.000	0.015	0.007	0.063	0.071	0.056
3/8	0.375	W	0.406	0.015	0.005	1.250	0.030	0.007	0.100	0.112	0.090
7/16	0.438	N	0.469	0.015	0.005	0.875	0.015	0.007	0.063	0.071	0.056
7/16	0.438	R	0.469	0.015	0.005	1.125	0.015	0.007	0.063	0.071	0.056
7/16	0.438	W	0.469	0.015	0.005	1.469	0.030	0.007	0.100	0.112	0.090
1/2	0.500	N	0.531	0.015	0.005	1.000	0.015	0.007	0.063	0.071	0.056
1/2	0.500	R	0.531	0.015	0.005	1.250	0.030	0.007	0.100	0.112	0.090
1/2	0.500	W	0.531	0.015	0.005	1.750	0.030	0.007	0.100	0.112	0.090
9/16	0.562	N	0.594	0.015	0.005	1.125	0.015	0.007	0.063	0.071	0.056
9/16	0.562	R	0.594	0.015	0.005	1.469	0.030	0.007	0.100	0.112	0.090
9/16	0.562	W	0.594	0.015	0.005	2.000	0.030	0.007	0.100	0.112	0.090
5/8	0.625	N	0.656	0.030	0.007	1.250	0.030	0.007	0.100	0.112	0.090
5/8	0.625	R	0.656	0.030	0.007	1.750	0.030	0.007	0.100	0.112	0.090
5/8	0.625	W	0.656	0.030	0.007	2.250	0.030	0.007	0.160	0.174	0.146
3/4	0.750	N	0.812	0.030	0.007	1.375	0.030	0.007	0.100	0.112	0.090
3/4	0.750	R	0.812	0.030	0.007	2.000	0.030	0.007	0.100	0.112	0.090
3/4	0.750	W	0.812	0.030	0.007	2.500	0.030	0.007	0.160	0.174	0.146
7/8	0.875	N	0.938	0.030	0.007	1.469	0.030	0.007	0.100	0.112	0.090
7/8	0.875	R	0.938	0.030	0.007	2.250	0.030	0.007	0.160	0.174	0.146
7/8	0.875	W	0.938	0.030	0.007	2.750	0.030	0.007	0.160	0.174	0.146
1	1.000	N	1.062	0.030	0.007	1.750	0.030	0.007	0.100	0.112	0.090
1	1.000	R	1.062	0.030	0.007	2.500	0.030	0.007	0.160	0.174	0.146
1	1.000	W	1.062	0.030	0.007	3.000	0.030	0.007	0.160	0.174	0.146
1 1/8	1.125	N	1.188	0.030	0.007	2.000	0.030	0.007	0.100	0.112	0.090
1 1/8	1.125	R	1.188	0.030	0.007	2.750	0.030	0.007	0.160	0.174	0.146
1 1/8	1.125	W	1.188	0.030	0.007	3.250	0.030	0.007	0.160	0.174	0.146
1 1/4	1.250	N	1.312	0.030	0.007	2.250	0.030	0.007	0.160	0.174	0.146
1 1/4	1.250	R	1.312	0.030	0.007	3.000	0.030	0.007	0.160	0.174	0.146
1 1/4	1.250	W	1.312	0.045	0.010	3.500	0.045	0.010	0.250	0.266	0.234
1 3/8	1.375	N	1.438	0.030	0.007	2.500	0.030	0.007	0.160	0.174	0.146
1 3/8	1.375	R	1.438	0.030	0.007	3.250	0.030	0.007	0.160	0.174	0.146
1 3/8	1.375	W	1.438	0.045	0.010	3.750	0.045	0.010	0.250	0.266	0.234
1 1/2	1.500	N	1.562	0.030	0.007	2.750	0.030	0.007	0.160	0.174	0.146
1 1/2	1.500	R	1.562	0.045	0.010	3.500	0.045	0.010	0.250	0.266	0.234
1 1/2	1.500	W	1.562	0.045	0.010	4.000	0.045	0.010	0.250	0.266	0.234
1 5/8	1.625	N	1.750	0.030	0.007	3.000	0.030	0.007	0.160	0.174	0.146
1 5/8	1.625	R	1.750	0.045	0.010	3.750	0.045	0.010	0.250	0.266	0.234
1 5/8	1.625	W	1.750	0.045	0.010	4.250	0.045	0.010	0.250	0.266	0.234
1 3/4	1.750	N	1.875	0.030	0.007	3.250	0.030	0.007	0.160	0.174	0.146
1 3/4	1.750	R	1.875	0.045	0.010	4.000	0.045	0.010	0.250	0.266	0.234
1 3/4	1.750	W	1.875	0.045	0.010	4.500	0.045	0.010	0.250	0.266	0.234
1 7/8	1.875	N	2.000	0.045	0.010	3.500	0.045	0.010	0.250	0.266	0.234
1 7/8	1.875	R	2.000	0.045	0.010	4.250	0.045	0.010	0.250	0.266	0.234
1 7/8	1.875	W	2.000	0.045	0.010	4.750	0.045	0.010	0.250	0.266	0.234
2	2.000	N	2.125	0.045	0.010	3.750	0.045	0.010	0.250	0.266	0.234
2	2.000	R	2.125	0.045	0.010	4.500	0.045	0.010	0.250	0.266	0.234
2	2.000	W	2.125	0.045	0.010	5.000	0.045	0.010	0.250	0.266	0.234

Row 28 (No.12): Source prints the outside diameter as "0.734Note 2" — the anti-coin OD of source Note 2; numeric value tabulated as printed.
Row 33 (1/4): Source prints the outside diameter as "0.734Note2" — the anti-coin OD of source Note 2; numeric value tabulated as printed.
Row 38 (3/8): Source prints the outside diameter as "0.734Note2" — the anti-coin OD of source Note 2; numeric value tabulated as printed.
Row 48 (9/16): Source prints the outside diameter as "1.469Note2" — the anti-coin OD of source Note 2; numeric value tabulated as printed.
Row 56 (7/8): Source prints the outside diameter as "1.469Note2" — the anti-coin OD of source Note 2; numeric value tabulated as printed.

Materials

Material and hardness specified per RFQ — plain washers are commonly low-carbon steel; through-hardened grades for high-strength bolted joints are an RFQ line, not a chart lookup

Ordering & documentation

Documents

Shipments are backed by Mill Test Certificate (MTC), Dimensional Report, Salt Spray Test Report on request, with full batch traceability from raw material to finished product. Quality management follows the owner-confirmed compliance list: ISO 9001:2015, RoHS, REACH. Exact document sets are confirmed on the order.

Quotation

The fastener family (ASME B18.21.1 Type B Plain Washers — Inch Series, Narrow / Regular / Wide (No.0 – 2 in)) plus the standard designation from your drawing — DIN / ISO / JIS / ASTM / ANSI, or a drawing for custom parts.
Size (diameter and length), thread type (metric or inch), property class or grade, and coating or finish.
Quantity per size and your target delivery date.
Destination country, and any required documents (for example a mill test certificate) so the quote includes them.

Sample & supply

Minimum order quantity is 10,000 pieces. Stock items run 3–7 days. Quantities or variants outside the standard range are confirmed at quotation.

Storage & shipping

Parts are packed for export and shipped factory-direct to buyers in Europe, Asia, the Americas and the Middle East. Store fasteners dry and protected until installation, and keep coated parts in their packaging until use; specific packing and preservation requirements can be stated on the order and confirmed at quotation.

Frequently asked questions

What separates Type B from Type A plain washers, and why does the full three-series chart matter when ordering?

Both types are plain flat washers under the same ASME B18.21.1 document; what differs is the tabulated dimension set per size. Type A's chart runs most small sizes in a single series and splits narrow/wide from the larger sizes up, while Type B carries narrow, regular and wide on every size from No.0 — so on a small screw (a No.4, a No.6), Type B is where the series choice exists at all: narrow where clearance or weight rules, regular as the default under a hex or socket bearing face, wide where the substrate is soft or thin and the washer must spread load or bridge an oversized hole. Because the same bolt size takes all three, order the series explicitly — "a washer for a No.6 screw" leaves the outside diameter undefined, and the spread within one size is large (No.6: OD 0.312/0.438/0.562 in across the series). The plus/minus tolerance pairs on every dimension are the goods-in answer: a washer measuring outside its printed limits is a nonconformance regardless of fit by eye. Note also the chart's flagged anti-coin outside diameters — deliberately non-stock ODs (0.734, 1.469 in) that keep washers out of coin-operated mechanisms; if your assembly passes through such hardware, those rows are the ones to match. For hardness, finish and material, the chart is silent — per RFQ.

What is the MOQ and lead time for washers on this standard?

The minimum order quantity is 10,000 pieces. Stock items ship in 3–7 days; non-stock items are confirmed at quotation. Common inch sizes are widely stocked; confirm the exact schedule against quantity and size mix at quotation.

Related knowledge

Which Washer Does the Joint Actually Need — Flat, Spring Lock, Belleville or Isolation?

Request a Quote

Get factory-direct pricing from the manufacturer.

What to include in your inquiry

✓ Standard and property class (e.g. DIN 912, ISO 4762, class 8.8) — or a drawing for custom parts.
✓ Sizes, lengths and thread type (metric or inch).
✓ Quantity per size and your target delivery date.
✓ Destination country, plus any coating or finish requirement.
✓ Any documents you need with the shipment (e.g. mill test certificate) so the quote includes them.
✓ Your inquiry goes straight to the factory team by email and gets a reply within 24 hours.

✓ Factory-direct pricing
✓ Standard and custom specifications
✓ Factory-direct export to buyers in Europe, Asia, the Americas and the Middle East
✓ Full fastener family support

ASME B18.21.1 Type B Plain Washers — Inch Series, Narrow / Regular / Wide (No.0 – 2 in)

Specifications

Materials

Ordering & documentation

Documents

Quotation

Sample & supply

Storage & shipping

Frequently asked questions

What separates Type B from Type A plain washers, and why does the full three-series chart matter when ordering?

What is the MOQ and lead time for washers on this standard?

Related grades & products

Related knowledge

Request a Quote

What to include in your inquiry