Hex bolts to DIN 931, 933, EN 14399 and to drawing

The hex bolt is the universal fastener: a hexagon head for the spanner, a threaded shank, and a nut or tapped hole as its counterpart. It is standardised as DIN 931 and ISO 4014 with a plain shank and partial thread, as DIN 933 and ISO 4017 threaded up to the head, as DIN 7990 for steel structures and as EN 14399 for preloaded HV connections. The American heavy hex bolt to ASME B18.2.1 has a larger head. Standard parts in common sizes come from mass production; RS Randack starts where the standard ranges end.

What RS Randack manufactures

• Special sizes: Long bolts such as M48 x 810, large diameters up to M180 with rolled threads, fine threads, special widths across flats.
• Bolts to drawing: Hex bolts with collar, spigot, fitted shank, cross hole, reduced shank, hexagon socket in the head, special heads.
• Special materials: Creep-resistant and stainless steels, duplex, nickel-based alloys, titanium, low-temperature steels, all with certificates.
• Small quantities and rush orders: From a single piece to small series; spare parts for plants at a standstill, in many cases within 24 hours.

Forged rather than turned heads

At RS Randack, heads are forged in closed dies; the grain flow follows the shape of the head, which makes the transition between head and shank considerably stronger than with a head machined from solid. Hot forming is typically up to M64, larger sizes on request; larger heads and special shapes are produced by turning and milling up to 300 mm diameter. Threads are rolled, after quenching and tempering on request. Coatings ranging from zinc flake and hot-dip galvanising to manganese phosphate with anti-friction coating, marking with property class and manufacturer’s mark, 3.1 or 3.2 inspection certificate.

What you should specify

Standard or drawing, diameter, length and thread length, property class or material, nut as an assembly, coating, certificate type and delivery date.