DIN 933 & DIN 931 Hex Bolt Dimensions & Weight Chart (ISO 4017 / ISO 4014)

How to read the dimensions

A hex bolt is ordered as d × L, for example M12 × 60. The nominal diameter d is the thread size; the length L is measured from under the head to the tip, not including the head. The head is defined by its width across flats s (the spanner size) and its height k. On a DIN 931 / ISO 4014 bolt only part of the length is threaded; that thread length is b. A DIN 933 / ISO 4017 bolt is threaded to the head.

Hex bolt head dimensions (mm)

Pitch is the ISO metric coarse thread. Head height k is the nominal value. Width across flats s differs between DIN and ISO for M10, M12, M14 and M22 — state which one your drawing requires.

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DIN 931 / ISO 4014 thread length b (mm)

Partial-thread bolts use a reference thread length that depends on the nominal length L: b = 2d + 6 for L ≤ 125 mm, 2d + 12 for 125 < L ≤ 200 mm, and 2d + 25 for L > 200 mm. If the bolt is too short to leave a plain shank, it is supplied threaded to the head, which in practice makes it a DIN 933 / ISO 4017 part.

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DIN 933 weight chart (kg per 1000 pcs)

Weight drives sea-freight cost, carton count and pallet loading, so it is worth checking before you compare landed prices. The values below are calculated for plain steel full-thread DIN 933 bolts (density 7.85 g/cm³) and checked against published catalogue weights to within about 3 %. Partial-thread DIN 931 bolts of the same size and length are slightly heavier because the plain shank has more steel than the thread. Hot-dip galvanizing adds a few percent, proportionally more on small sizes.

The DIN 931 weight chart follows below. For any other length, nuts, washers and threaded rods, use the fastener weight calculator.

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• Steel fasteners usually fill a 20 ft container by weight before volume. Plan on roughly 20–25 tonnes of packed product per 20 ft container, subject to carrier and local road-weight limits.
• For mixed orders, multiply quantity by the weight per piece for each line and add about 3–5 % for cartons and pallets.

DIN 931 weight chart (kg per 1000 pcs)

Calculated for plain steel partial-thread DIN 931 / ISO 4014 bolts (density 7.85 g/cm³). Columns are the bolt length L in mm; “—” marks lengths outside the usual commercial range for that size. A DIN 931 bolt is heavier than a DIN 933 bolt of the same size and length because the plain shank carries more steel than the thread.

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Common lengths

The preferred length series runs 6, 8, 10, 12 and 16 mm, then 5 mm steps from 20 to 70 mm, 10 mm steps from 70 to 160 mm and 20 mm steps beyond. Not every length exists for every diameter; very short lengths apply to small sizes and very long lengths to large ones. Lengths outside the standard series, extra-long bolts and short partial-thread bolts are usually made to order and quoted with the 25–30 day production lead time.

DIN 933 vs ISO 4017: what actually changes

DIN 931 and DIN 933 have been withdrawn and replaced by ISO 4014 and ISO 4017, but the DIN numbers are still the most common way buyers describe these bolts. For most sizes the parts are dimensionally interchangeable. The difference that matters on site is the spanner size for M10, M12, M14 and M22, which affects tools, socket sets, automated tightening and any mating part sized to the head.

Tolerances and product grades are defined by the ISO standard and its referenced documents, and property classes come from ISO 898-1 in both cases. If your drawing says DIN 933 and you are willing to accept ISO 4017, say so in the RFQ; otherwise a supplier should quote exactly what the drawing names.

Property classes and head markings

Values are from ISO 898-1 for carbon and alloy steel and ISO 3506-1 for stainless steel. ISO 898-1 requires hexagon head bolts in classes 4.6 to 12.9 to carry the property class and the manufacturer's identification mark where the shape allows, normally on the head. Ask for a photo of the head marking with your first sample.

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How to specify a hex bolt in your RFQ

• Standard and edition: DIN 933, DIN 931, ISO 4017 or ISO 4014, and whether the alternative is acceptable.
• Size × length, e.g. M12 × 60, and full or partial thread.
• Property class (4.8, 8.8, 10.9, 12.9) or stainless grade (A2-70, A4-80).
• Finish with a full designation: plain, zinc plated (e.g. ISO 4042 Zn8/Cn/T0), hot-dip galvanized to ISO 10684, or zinc flake.
• Matching nuts and washers, quantity per size, packaging, marking and inspection documents such as an EN 10204 3.1 certificate.