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McMaster 91190A570 Black-Oxide Steel Split Lock Washer, for M12 Socket Head Screws, 12.7 mm ID, 18 mm OD, Pack of 100
McMaster 91190A570 Black-Oxide Steel Split Lock Washer, for M12 Socket Head Screws, 12.7 mm ID, 18 mm OD, Pack of 100
McMaster 91190A570 Black-Oxide Steel Split Lock Washer, for M12 Socket Head Screws, 12.7 mm ID, 18 mm OD, Pack of 100
McMaster 91190A570 Black-Oxide Steel Split Lock Washer, for M12 Socket Head Screws, 12.7 mm ID, 18 mm OD, Pack of 100
McMaster 91190A570 Black-Oxide Steel Split Lock Washer, for M12 Socket Head Screws, 12.7 mm ID, 18 mm OD, Pack of 100
McMaster 91190A570 Black-Oxide Steel Split Lock Washer, for M12 Socket Head Screws, 12.7 mm ID, 18 mm OD, Pack of 100
McMaster 91190A570 Black-Oxide Steel Split Lock Washer, for M12 Socket Head Screws, 12.7 mm ID, 18 mm OD, Pack of 100
McMaster 91190A570 Black-Oxide Steel Split Lock Washer, for M12 Socket Head Screws, 12.7 mm ID, 18 mm OD, Pack of 100
McMaster 91190A570 Black-Oxide Steel Split Lock Washer, for M12 Socket Head Screws, 12.7 mm ID, 18 mm OD, Pack of 100
McMaster 91190A570 Black-Oxide Steel Split Lock Washer, for M12 Socket Head Screws, 12.7 mm ID, 18 mm OD, Pack of 100
McMaster 91190A570 Black-Oxide Steel Split Lock Washer, for M12 Socket Head Screws, 12.7 mm ID, 18 mm OD, Pack of 100
McMaster 91190A570 Black-Oxide Steel Split Lock Washer, for M12 Socket Head Screws, 12.7 mm ID, 18 mm OD, Pack of 100
McMaster 91190A570 Black-Oxide Steel Split Lock Washer, for M12 Socket Head Screws, 12.7 mm ID, 18 mm OD, Pack of 100
McMaster 91190A570 Black-Oxide Steel Split Lock Washer, for M12 Socket Head Screws, 12.7 mm ID, 18 mm OD, Pack of 100

McMaster 91190A570 Black-Oxide Steel Split Lock Washer, for M12 Socket Head Screws, 12.7 mm ID, 18 mm OD, Pack of 100

$58.69 - $58.69
$58.69
$58.69 - $58.69
$58.69

Stop socket head screws from loosening due to mild vibration. These washers have a small diameter to fit under screws with narrow heads, but are still thick enough to keep fasteners secure. While they're not as vibration resistant as other lock washers, they are a great fit for electrical panels, light fixtures, and other light duty assemblies. Split lock washers are not reusable, and they only work with fasteners that have right-hand threads. Also known as high-collar lock washers.

Black-Oxide Steel—Best for dry environments since moisture will cause these washers to rust. They have a dark, matte appearance.

For Use With Socket Head Screws
For Screw Size M12
ID 12.7 mm
OD 18.0 mm
Thickness 2.3 mm to 2.7 mm
Certificate Form Digital
Certificate Type Material Certificate with Traceable Lot Number
Finish Black Oxide
Hardness Rockwell C44
Material Steel
Specifications Met DIN 7980
System of Measurement Metric
Washer Type Split
Country of Origin United States, Belgium, Canada, China, France, Germany, India, Indonesia, Italy, Japan, Malaysia, Mexico, Philippines, Poland, South Korea, Switzerland, Taiwan, Thailand, Vietnam
DFARS Compliance Specialty Metals COTS-Exempt
Export Control Classification Number (ECCN) EAR99
REACH Compliance REACH (EC 1907/2006) (02/04/2026, 253 SVHC) Compliant
RoHS Compliance RoHS 3 (2015/863/EU) Compliant
Schedule B Number 731821.0000
U.S.–Mexico–Canada Agreement (USMCA) Qualifying No