STAINLESS STEEL WOOD CONSTRUCTION WASHERS SQUARE HOLE DIN 440V

Wood Construction Washers Square Hole DIN 440V — Coach bolts have a square section immediately under the head specifically to stop them spinning while the nut is tightened from the other side, and DIN 440V is the washer built to use that feature - its square hole keys directly onto the bolt's square shoulder, locking the two together so the whole bolt does not rotate as torque is applied. Without that anti-rotation function, tightening a coach bolt in timber usually means holding the head steady with a second tool or by hand, which gets impractical fast once the bolt is buried in a joint or the work is overhead. Everything else about DIN 440V follows the same logic as its round-hole sibling DIN 440R: a generous outside diameter and thickness to spread clamping load across timber fibres without crushing them, making it the natural choice for fencing, decking substructure, sheds, and general timber-frame fixing work wherever coach bolts rather than coach screws are specified. It only works with square-shanked coach bolts - fitting it over a plain round shank will not seat correctly and provides none of the anti-rotation benefit, so it is not a general substitute for DIN 440R. Material selection is exposure-led: internal or short-term external timber work is usually fine in mild steel with a protective zinc finish, but for decking, fencing, and anything left outdoors long-term, A2 (304-equivalent) stainless resists the staining and gradual weakening that a rusting washer causes in the surrounding timber. A4 (316-equivalent) only becomes worth the premium in coastal or heavily salted settings. To specify correctly, confirm the coach bolt's shank and square-shoulder dimensions, match the square hole accordingly, and choose the outside diameter and material to suit both the timber species and how exposed the finished fixing will be.

FAQs
Can DIN 440V washers be used with standard round-shank bolts?
No. The square hole is sized to the square section of a coach bolt and will not seat correctly, or provide any anti-rotation benefit, on a plain round shank.

How does DIN 440V differ from DIN 440R?
DIN 440R has a round hole for standard round-shank fasteners, while DIN 440V's square hole engages the square shoulder of a coach bolt to stop it spinning as the nut is tightened.

Do I need to orient the square hole a particular way when fitting?
No - it simply needs to engage over the bolt's square shoulder as the assembly is brought together before tightening; there is no handed orientation to worry about.