USS Flat Washer, Galvanized

Low carbon USS flat washers are used under bolt heads or nuts to increase the bearing surface area, or to offer protection so that the nut or bolt can be rotated without distortion of the bearing surface. Flat washers are also used to give tightness to a joint, to prevent leakage, and especially to distribute pressure under the head of a bolt or nut. Dimensional specifications are governed by ASME B18.21.1. USS (United States Standard) flat washers have a larger outer diameter than structural ASTM F436 flat washers, and can be utilized in nearly any application. ASTM F844 covers the standard specifications for unhardened steel flat washers for general use. Hot dip galvanizing provides a highly corrosion resistant finish, made of sacrificial zinc.

Technical Data

Governing StandardsUSS Flat Washer

ASTM F844	Covers standard, unhardened steel washers for general use.
ASME B18.21.1	Covers the dimensional requirements, physical properties, and related test methods for helical spring-lock washers (#0 through 3 inches), tooth-lock washers (#2 through 1 ¼ inches), and plain washers (#0 through 3 inches).

Dimensional SpecificationsUSS Flat Washer

Per ASME B18.21.1-2009
Size	Nominal	A			B			C
		Inside Diameter			Outside Diameter			Mean Section Thickness
		Basic	Tolerance Plus	Tolerance Minus	Basic	Tolerance Plus	Tolerance Minus	Basic	Max	Min
		Basic	Tolerance Plus	Tolerance Minus	Basic	Tolerance Plus	Tolerance Minus	Basic	Max	Min
#6	0.1380	0.1560	0.0080	0.0050	0.3750	0.0150	0.0050	0.0490	0.0650	0.0360
#8	0.1640	0.1880	0.0080	0.0050	0.4380	0.0150	0.0050	0.0490	0.0650	0.0360
#10	0.1900	0.2190	0.0080	0.0050	0.5000	0.0150	0.0050	0.0490	0.0650	0.0360
#12	0.2160	0.2500	0.0150	0.0050	0.5620	0.0150	0.0050	0.0650	0.0800	0.0510
1/4	0.2500	0.3120	0.0150	0.0050	0.7340	0.0150	0.0070	0.0650	0.0800	0.0510
5/16	0.3125	0.3750	0.0150	0.0050	0.8750	0.0300	0.0070	0.0830	0.1040	0.0640
3/8	0.3750	0.4380	0.0150	0.0050	1.0000	0.0300	0.0070	0.0830	0.1040	0.0640
7/16	0.4375	0.5000	0.0150	0.0050	1.2500	0.0300	0.0070	0.0830	0.1040	0.0640
1/2	0.5000	0.5620	0.0150	0.0050	1.3750	0.0300	0.0070	0.1090	0.1320	0.0860
9/16	0.5625	0.6250	0.0150	0.0050	1.4690	0.0300	0.0070	0.1090	0.1320	0.0860
5/8	0.6250	0.6880	0.0300	0.0070	1.7500	0.0300	0.0070	0.1340	0.1600	0.1080
3/4	0.7500	0.8120	0.0300	0.0070	2.0000	0.0300	0.0070	0.1480	0.1770	0.1220
7/8	0.8750	0.9380	0.0300	0.0070	2.2500	0.0300	0.0070	0.1650	0.1920	0.1360
1	1.0000	1.2500	0.0300	0.0070	2.5000	0.0300	0.0070	0.1650	0.1920	0.1360
1 1/8	1.1250	1.3750	0.0300	0.0070	2.7500	0.0300	0.0070	0.1650	0.1920	0.1360
1 1/4	1.2500	1.3750	0.0300	0.0070	3.0000	0.0300	0.0070	0.1650	0.1920	0.1360
1 3/8	1.3750	1.5000	0.0450	0.0100	3.2500	0.0450	0.1000	0.1800	0.2130	0.1530
1 1/2	1.5000	1.6250	0.0450	0.0100	3.5000	0.0450	0.0100	0.1800	0.2130	0.1530
1 5/8	1.6250	1.7500	0.0450	0.0100	3.7500	0.0450	0.0100	0.1800	0.2130	0.1530
1 3/4	1.7500	1.8750	0.0450	0.0100	4.0000	0.0450	0.0100	0.1800	0.2130	0.1530
1 7/8	1.8750	2.0000	0.0450	0.0100	4.2500	0.0450	0.0100	0.1800	0.2130	0.1530
2	2.0000	2.1250	0.0450	0.0100	4.5000	0.0450	0.0100	0.1800	0.2130	0.1530
2 1/4	2.2500	2.3750	0.0450	0.0100	4.7500	0.0450	0.0100	0.2200	0.2480	0.1930
2 1/2	2.5000	2.6250	0.0450	0.0100	5.0000	0.0450	0.0100	0.2380	0.2800	0.2100
2 3/4	2.7500	2.8750	0.0650	0.0100	5.2500	0.0650	0.0100	0.2590	0.3100	0.2280
3	3.0000	3.1250	0.0650	0.0100	5.5000	0.0650	0.0100	0.2840	0.3270	0.2490

All dimensions are in inches.

USS Flat Washer, Galvanized

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Diameter	Inside Diameter	Outside Diameter	Thickness	Item #	Availability	Price	Quantity
1/4	0.3120	0.7340	0.0650	WFGA025	In Stock	$0.02951/EA	EA	EA
5/16	0.3750	0.8750	0.0830	WFGA031	In Stock	$0.06208/EA	EA	EA
3/8	0.4380	1.0	0.0830	WFGA037	In Stock	$0.08803/EA	EA	EA
7/16	0.5	1.25	0.0830	WFGA043	In Stock	$0.13977/EA	EA	EA
1/2	0.5620	1.3750	0.1090	WFGA050	In Stock	$0.17381/EA	EA	EA
9/16	0.6250	1.4690	0.1090	WFGA056	In Stock	$0.28335/EA	EA	EA
5/8	0.6880	1.75	0.1340	WFGA062	In Stock	$0.31382/EA	EA	EA
3/4	0.8120	2.0	0.1480	WFGA075	In Stock	$0.50685/EA	EA	EA
7/8	0.9380	2.25	0.1650	WFGA087	In Stock	$0.61442/EA	EA	EA
1	1.25	2.5	0.1650	WFGA100	In Stock	$0.82576/EA	EA	EA
1 1/8	1.3750	2.75	0.1650	WFGA112	In Stock	$1.88085/EA	EA	EA
1 1/4	1.3750	3.0	0.1650	WFGA125	In Stock	$1.10897/EA	EA	EA
1 3/8	1.5	3.25	0.18	WFGA137	In Stock	$1.33532/EA	EA	EA
1 1/2	1.6250	3.5	0.18	WFGA150	In Stock	$2.08027/EA	EA	EA
1 5/8	1.75	3.75	0.18	WFGA162	In Stock	$1.19439/EA	EA	EA
1 5/8	2.0	4.25	0.18	WFGA187	In Stock	$2.89883/EA	EA	EA
1 3/4	1.8750	4.0	0.18	WFGA175	In Stock	$1.48027/EA	EA	EA
2	2.1250	4.5	0.18	WFGA200	In Stock	$3.28284/EA	EA	EA

USS Flat Washer, Galvanized

Technical Data

Tab 1

Governing StandardsUSS Flat Washer

Tab 4

Dimensional SpecificationsUSS Flat Washer

Product Specification

Grade

Diameter

Thickness

Outside Diameter

Inside Diameter