Slotted Square Washer Frequently Asked Questions
Below are answers to some of the most common questions about slotted square washers.
What are slotted square washers?
Slotted square washers combine a square outer profile with a radial slot extending from the center hole to one edge, allowing the washer to be placed around a fastener shank without removing the fastener. The square outer shape provides a large, stable bearing surface for structural and timber fastening applications, while the slot enables installation and removal with the fastener only loosened. Superior Washer stocks 23 slotted square configurations in OD sizes of 1.5", 1.575", and 2.0", in thicknesses from 0.010" to 0.125".
What is the difference between slotted round and slotted square washers?
Both types feature a radial slot for installation without full fastener removal. The difference is the outer profile: slotted round washers have a circular OD, while slotted square washers have a square OD that provides a larger and more stable bearing footprint. Slotted square washers are preferred in timber construction, structural steel, and heavy-duty applications where maximum bearing area is needed along with quick-access installation.
What applications use slotted square washers?
Slotted square washers are widely used in timber construction, structural connections, equipment base plates, agricultural machinery, and any structural fastening application requiring a large bearing surface and the ability to install or remove the washer without full disassembly. They are common in post-and-beam construction, decking, and heavy equipment mounting.
What materials are slotted square washers available in?
Slotted square washers are produced in steel, stainless steel, brass, aluminum, and other materials on request. The stocked catalog includes multiple thickness options for each OD size.
Can you produce custom slotted square washers?
Yes. We manufacture custom slotted square washers to your OD, ID, slot width, and thickness specifications. Custom materials including 17-4 PH stainless steel and other specialty alloys are available. Contact us via the Quick Quote form or call NY (631) 273-8282 or SC (803) 366-3250.
Are your slotted square washers made in the USA?
Yes. All slotted square washers are manufactured in the United States under our ISO 9001:2015 certified Quality Management System at our Hauppauge, NY and Rock Hill, SC facilities.
Need a round slotted profile instead? Browse the full flat washers catalog to see all shapes and materials available.
