Fender Washers

What is a fender washer?

A fender washer is a flat washer with a large outside diameter (OD) compared to its hole. It spreads clamp load over a wider area. Use it on thin sheet metal, soft materials, and oversized or slotted holes.

How fender washer sizes are listed

Inch fender washers are listed as screw or bolt size x OD. A 1/4" x 1 1/4" fender washer fits a 1/4" bolt and is 1-1/4" across. Some titles add the thickness, for example 1/4" x 1" x 0.050. Metric fender washers are listed as size-OD in mm, for example M6-18 (for an M6 bolt, 18 mm OD) or M10 x 30mm. Metric fender washers follow DIN 9021 sizes.

Each bolt size comes in several ODs. A 1/4" fender washer is stocked from 1" to 2" OD, and a 1/2" fender washer from 1-1/4" to 3" OD. See the size table below.

Choose the material

• Steel: low carbon steel in zinc, black oxide, plain and hot-dip galvanized. Use hot-dip galvanized washers with hot-dip galvanized bolts and nuts.
• 18-8 stainless: passivated, and one size (1/4" x 1-1/4") in black oxide. On stainless, black oxide is cosmetic.
• 316 stainless: passivated, in inch and metric sizes. Choose 316 over 18-8 where chlorides or salt are present.
• Metric stainless: A2 stainless and 316 (A4). See 18-8 stainless and 316 stainless.

Thick and extra thick fender washers

Extra thick fender washers are stocked in zinc-plated steel from 1/4" to 1/2" bolt size. Extra thick fender washers are 0.108" to 0.132" thick. Where a title gives the thickness, it is listed in inches, for example 0.050 or 0.078.

Bulk fender washers and pack sizes

Most fender washers come as a Package or a Bulk Box. Piece counts depend on size and material, for example 2 / 25 for steel, 100 / 1,000 for stainless, and up to 1,000 / 10,000 for small metric sizes. Need volume pricing? See wholesale.