M16 (5/8") x 32.4mm x 3.1 mm Galvanised HSFG Structural Washers High Tensile K0 AS1252.2016

About HSFG Structural K0 Washers

K0 Structural Washers are thick hardened flat washers matched to the K0 Structural Bolt and Nut assembly system, certified to AS 1252:2016. Used under both the bolt head and the nut on a K0 structural joint to distribute the high preload of the HSFG bolt without indenting the connecting plates. Galvanised, Class 8.8 equivalent hardness. Use ONLY with matched K0 bolts and nuts. The three small nibs (also called bumps or dimples) on the outside diameter are the visible identifier - they let inspectors and installers tell a structural washer apart from a standard heavy round washer at a glance. If your washer does not have the three nibs, it is NOT a structural-rated washer regardless of size.

Recommended use The standard outdoor finish for timber framing, fencing, decking, retaining walls and treated-timber contact (H3 and H4 treated pine). Decades of corrosion protection in most outdoor and rural environments.

Frequently Asked Questions

Material & Coating

Galvanised Hot-dip galvanised carbon steel. The standard outdoor finish; thick zinc coating gives decades of corrosion resistance. The right choice for trailer chassis, mast and pole mounting, structural pipe clamping and outdoor tank fittings.

Important Performance in permanent coastal applications (within 300 metres of the sea) is reduced. Refer to AGA technical bulletins or contact us for the right grade for severe marine exposure.

Class Metric fasteners are classified as class 2, 4.6, 8.8, 10.9, 12.9, 14.9. See the head marking chart and full strength table.

How to Order the Right Size Washer

Washer sizing Washer sizes can be confusing, so here is the quickest way to find the right one. If you already have a bolt or screw, match the bolt size: an M6 bolt takes an M6 washer, M10 takes M10, and so on. Look for the size at the start of the description (e.g. 'M6 Flat Round Washer').

If you only have a loose washer to match, measure the inside diameter and pick the next size down. The washer's inside is always slightly larger than the matching bolt so it slides on freely. For example, an inside measurement of approximately 6.50mm means you need an M6 washer; 17.25mm means you need an M16 washer.

The outside diameter is measured outside-to-outside. Thickness varies between batches - washers are not precision-made fasteners and slight variations are normal. All published measurements on this site should be used as a guide only.

Need every size? See our full washer gauge sizing chart for the complete SWG range (8g to 24g) in mm and inch.

Resources

Pricing & Delivery

Includes GST, a Tax Invoice and Free Standard Delivery anywhere in Australia.

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Disclaimer

Technical data Researched and compiled from numerous industry sources for the sole purpose of providing basic information. All material is advisory only and its use by anyone is entirely voluntary. Reliance on it for any purpose by anyone is at the sole risk of that person, and Bolt and Nut Australia is not responsible for any loss, claim or damages arising therefrom. In developing this information, Bolt and Nut Australia has made a determined effort to present it accurately.

Measurements Sizes are taken from supplier catalogues or hand-measured and should be used as a guide. Minor variation between batches is normal. Stock is sourced from various suppliers, so differences may exist between batches in markings, appearance or finish.

Product Photos & PDF Data Sheets Represent the product type, not exact size. PDFs are a reference guide only. Specifications may change without notice.

If you see any problems with any of our specifications or you require additional information please contact us.