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SCREWS SERIES · DIN 571

Coach Screw (Self-Tapping Lag Screw)

Imported from approved mills · Stocked in Umm Al Quwain, U.A.E.

Coach screws are the heavy-duty timber fastener — a hex-head screw with a coarse wood thread driven with a spanner — and we stock DIN 571 in Umm Al Quwain from M6 to M20 and 25 to 300 mm long, zinc plated, hot-dip galvanized and stainless A2 / A4, with washers to suit.

ORIGIN Imported from approved mills STOCK Held in Umm Al Quwain warehouse CERT EN 10204 3.1 test certificates TRACE Lot-level traceability
Technical data

Specification summary

OriginImported & stocked
MaterialCarbon steel
FinishHot-dip galvanized · Zinc plated
SizeM6–M20
Length25 – 300 mm
StandardDIN 571
HeadHex (square / Torx to order)
VERIFY AGAINST YOUR PROJECT SPECIFICATION AND THE CURRENT STANDARD REVISION. NON-LISTED SIZES, GRADES AND FINISHES AVAILABLE ON REQUEST.

Order data

  • Origin Imported · Stocked
  • Category Screws Series
  • Supply Loose · Sets · Bulk
  • Export GCC · MENA · Africa
  • Also at Maimoon
TECHNICAL DATA & SPECS
About this product

Coach Screw (Self-Tapping Lag Screw) explained

Coach screws are the heavy-duty timber fastener — a hex-head screw with a coarse wood thread driven with a spanner — and we stock DIN 571 in Umm Al Quwain from M6 to M20 and 25 to 300 mm long, zinc plated, hot-dip galvanized and stainless A2 / A4, with washers to suit.

A coach screw (lag screw, lag bolt) has a square or hexagon head, a plain shank and a tapered, coarse wood-screw thread. Driven into a pilot hole in timber with a socket or spanner, it develops high withdrawal resistance without a nut, so it is used where only one side is accessible: fixing timber to timber, brackets to joists, and — with an expanding plug — steel to masonry and concrete. Larger sizes are used for sleeper fixings, timber-frame structures and pergolas.

Applications

  • Timber construction, decking and pergolas
  • Joist hangers, brackets and post bases
  • Sleepers, retaining walls and landscaping
  • Machinery and equipment on timber floors
  • Steel to masonry with expansion plugs
  • Playground, fencing and gate hardware

Standards, grades & finishes

Screws to DIN 571 (hex head), sizes M6 to M20, lengths 25 to 300 mm, carbon steel class 4.6 / 4.8, stainless A2 / A4 to ISO 3506. Finishes zinc plated to ISO 4042, hot-dip galvanized to ISO 1461, plain stainless. Square-head and Torx-drive coach screws, and coach screws with DIN 440 timber washers, to order.

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.

Frequently asked

Coach Screw (Self-Tapping Lag Screw) — FAQ

What pilot hole for a coach screw?

About 70% of the shank diameter for the threaded length in softwood (e.g. 7 mm for M10) and 80–85% in hardwood; clearance hole for the plain shank.

Can coach screws be used in concrete?

Yes, with a matching expansion plug (shield) — the coach screw drives into the plug, which expands in the drilled hole.

Which finish for outdoor timber?

Hot-dip galvanized or A4 stainless; zinc plating is for indoor use. Note that treated timber (CCA / ACQ) is corrosive to zinc — use stainless where in doubt.

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