M8 x 1.25p Metric Coarse Stainless A2-35 G304 Hex Thin Lock Nuts DIN 439

About Hex Thin Lock Nuts

Hex Thin Lock Nuts are half-height hex nuts used as a jam nut. A second, thinner nut is tightened against a primary nut to lock both in place by friction. Also useful where head clearance is tight and a full-height nut won't fit. The thin form means full clamp capacity is lower than a standard nut, so use in pairs (one thin, one full) for the locking effect.

Recommended use Outdoor architectural, food and pharmaceutical equipment, and general indoor / outdoor applications where annealed ductility matters more than peak strength. Pick A4-grade G316 instead for coastal, marine or aggressive chemical environments.

Frequently Asked Questions

Material & Coating

Stainless A2-35 G304 Austenitic G304 stainless steel in soft (annealed) condition. Property class 35 designates a minimum tensile strength of 350 MPa with a 0.2 percent proof stress of 180 MPa. The general-purpose stainless grade for outdoor and most chemical environments where chloride exposure is moderate.

Important Lower tensile strength than A2-70 (350 MPa vs 700 MPa). Specify A2-70 G304 for higher-load applications, or A4-grade G316 for marine / coastal use. Do not pair stainless with plain or galvanised steel in wet service.

Class Stainless fasteners are classified by property class: A2-35 / A2-50 / A2-70 in G304 stainless, and A4-40 / A4-70 / A4-80 (Bumax 88) in G316. The first digit indicates the alloy and the second is the minimum tensile strength in 100 MPa increments (e.g. A4-70 = 700 MPa). See the head marking chart and full strength table.

Thread Pitch & Terminology

Thread Pitch (Metric) Metric fasteners measure thread pitch as the distance between thread peaks, expressed in millimetres. Metric also branches into three series: coarse (the default; widest tolerance, easiest to tap), fine (a tighter pitch for higher clamp load or thinner walls), and extra fine (the tightest pitch, used for thin-wall tube, precision instruments, and aerospace fittings where vibration loosening must be minimised). Always match the series as well as the size - a metric fine nut will not engage a metric coarse bolt of the same diameter, and an extra fine nut will not engage either. This product has a 1.25mm coarse pitch, meaning the peaks are 1.25mm apart.

How to Measure

A nut is named after the bolt it fits. An M10 nut fits an M10 bolt - the 10mm is the bolt's diameter, not anything on the nut itself.

The two quick checks are the spanner size across the flats, and the hole, which always measures smaller than the named size (an M10 nut reads about 8.5mm through the hole).

The most reliable test of all: thread it onto a bolt you know. The right nut spins on by hand with no force.

Resources

Pricing & Delivery

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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 thread length, 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.