Form B Washer Specification

The british standard for metric series metal washers bs4320 written in 1968 coined the term form.

Form b washer specification. Bs 4320 pdf bs 4320 standard pdf bs 4320 flat washer pdf bs 4320 specification pdf bs 4320 dimensions bs 4320 form a form b form c form d form e form f form g. 20 item s sort by. All dimensions are in inches. See detailed stock chart here.

B the 0 734 inch 1 156 inch and 1 469 inch outside diameters avoid washers which could be used in coin operated devices. If any of these measurements are not correct on the manufactured part is can not be called a form a washer. High quality form a form b form c and form d washers available from fastenright ltd in a range of sizes and materials from fastenright from m2 to m24 and higher. It s important to note that there are tolerances allowed within the specification.

Bolt size inside diameter outside diameter. A2 a4 stainless steel. Washer knowledge flat washer size comparisons. Din 125 b plain washers form b current norm.

Din en iso 7090 equivalent norms. Designation n narrow and the standard plate w wide these sizes as well as all other sizes of type a plain washers are generally specified by id od and thickness dimensions. Type b is a series of flat washers with tighter tolerances where outside diameters are categorized as narrow regular or wide for specific bolt sizes. Metric form a flat washer steel 140hv din125a.

Washers can also be specially manufactured in any material dimensions for form b washers. By using these tables we can see that an m10 form a washer will have an internal diameter of 10 5mm an external diameter of 21mm and be 2mm thick. Type is not to be confused with form but often is. Form a is identical to the more popular german specification din125.

Non standard sizes and materials and special washers made to order for fast dispatch uk worldwide.