Square head bolts are the traditional holding-down bolt for cast-in column bases — the square head locks in the anchor plate and stops the bolt turning while the nut is tightened. We supply them from M12 to M125 in carbon and alloy steel, hot-dip galvanized or self colour, with anchor plates, tubes and nuts to BS 7419 or ASTM F1554.
A square head bolt has a four-sided head that can be held by a spanner or, in foundation work, sits against a square hole in an anchor plate or inside a tube so it is captive during installation. As a holding-down bolt (HD bolt) it is cast into the foundation with a plate at the bottom and a sleeve or cone around the shank so the bolt can be moved slightly to align with the base plate.
Applications
- Steel column base plate anchorage (BS 7419 HD bolts)
- Machinery and turbine foundations
- Crane gantry columns and rail tracks
- Portal frame and PEB foundations
- Bridge bearings and parapet posts
- Heavy equipment skids and vessel supports
Standards, grades & finishes
Bolts to BS 7419 (square head holding-down bolts, grade 4.6 / 8.8), ASTM F1554 Gr 36 / 55 / 105, DIN 480 or to drawing. Material S275JR, S355JR, EN8 or alloy steel with mill certificates. Threads ISO 965 6g or UNC. Supplied with anchor plates, tubes / cones, nuts (ISO 4032 / A563) and plate washers. Finish self colour or hot-dip galvanized to ISO 1461.
This item is imported from approved mills and held in stock in our Umm Al Quwain warehouse alongside the anchor bolts, studs and plate washers we manufacture ourselves, so complete bolt sets ship from one source. Tensile, hardness and chemical testing is carried out by independent UAE-accredited laboratories, and EN 10204 3.1 certificates are issued with every batch. We supply across the GCC, MENA and Africa.