Doughty Gravlock Coupler per pair
Doughty Gravlock Coupler per pair £51.50
  • Doughty Gravlock Couplers T29497, pair of S275 mild steel girder clamps with passivate finish, Grade 8.8 fixings, for attaching 48mm tube to steel I-beam flanges.
  • Doughty Gravlock Couplers T29497, pair of steel gravlock couplers attaching a 48mm black tube to a red steel I-beam flange in a stage or structural installation. - imagen 2
  • Doughty Gravlock Couplers T29497, pair of steel gravlock couplers attaching a 48mm black tube to a yellow steel I-beam flange in a stage or structural installation. - imagen 3
  • Doughty Gravlock Coupler T29497, technical dimensions diagram showing flange range 0–45mm, tube diameter Ø48mm, overall width 105mm, bolt M16x80, 1/2" BSW 12 TPI. Must be used in pairs. - imagen 4

Doughty Gravlock Coupler per pair

Doughty Engineering |
SKU: T29497
£61.80incl. VAT

Incl. VAT. Shipping calculated at checkout.

In stock
Shipping 3–7 days
Minimum order value of £45 Minimum order value of £45 is required to place an order for all Doughty products. 1 Year Warranty
Steel: Zinc Plated
  • WLL 600kg Per Pair. Heavy-duty S275 mild steel construction with Grade 8.8 fixings. Built for permanent structural installations in theatres, studios and arenas.
  • Fits Flanges up to 45mm. Clamps directly onto standard steel I-beam and RSJ flanges. No drilling or welding required.
  • Attaches 48mm Tube at 90°. The industry standard method for hanging lighting bars and truss from structural steelwork when no ceiling grid is available.
  • Must Be Used in Pairs. Sold and supplied as a pair. Never use a single coupler. Tighten to a minimum torque of 54Nm with M16 x 80 bolts.
View full Description Technical data
american_expressapple_paydiners_clubdiscovergoogle_payklarnamaestromasterpaypalshopify_payunionpayvisa
klarna. Add an item to see installment options

You may also like

Doughty Gravlock Couplers — Steel Girder Clamps for 48mm Tube

The Doughty Gravlock Couplers are heavy-duty steel clamps designed to attach standard 48mm tube directly to the flange of a steel I-beam or RSJ at 90° — creating a secure, load-rated fixing point without drilling, welding, or modifying the structure. Used in theatres, studios, arenas, and live event venues where there is no grid or ceiling track, they allow riggers to hang lighting bars and truss directly from the building's structural steelwork. With a WLL of 600kg per pair and S275 mild steel construction with Grade 8.8 fixings, they are built for permanent and semi-permanent installations where reliability is critical. Must be used in pairs — sold as a pair.

Also available as a Gravlock Swivel Coupler for installations where the tube needs to run at a different angle to the beam.

Key Features:

  • WLL 600kg per pair — heavy-duty load rating for permanent structural installations
  • Attaches 48mm tube to steel I-beam and RSJ flanges at 90° — no drilling or welding required
  • Fits flanges up to 45mm (1.77") — compatible with standard structural steel sections
  • S275 mild steel construction with Grade 8.8 fixings — high strength and durability
  • M16 x 80 bolts with 1/2" BSW 12 TPI thread — minimum tightening torque 54Nm
  • Passivate finish — corrosion resistant, colour may vary
  • Must be used in pairs — sold as a pair (T29497)
  • British designed and manufactured by Doughty Engineering

Compatible Accessories:

Browse our full range of Doughty steel clamps, Doughty Engineering products and entertainment and stage rigging at MTN Shop.

Frequently Asked Questions

What is the WLL of the Doughty Gravlock Couplers?
The Doughty Gravlock Couplers have a Working Load Limit of 600kg per pair. The WLL applies to the pair as a unit — never use a single coupler as a standalone fixing.
What size flanges and tube diameter do the Doughty Gravlock Couplers fit?
The couplers fit steel I-beam and RSJ flanges from 0mm to 45mm (1.77") thick and are designed for standard 48mm OD tube — the industry standard for stage lighting bars, scaffold tube and truss.
Why must the Doughty Gravlock Couplers be used in pairs?
A single coupler cannot prevent the tube from rotating around the flange under load. Using two couplers spaced apart distributes the load correctly and prevents rotation. The WLL of 600kg is only valid when both couplers are installed and tightened to the minimum torque of 54Nm.
Do I need a safety bond when using Doughty Gravlock Couplers overhead?
Yes. A safety bond is a mandatory secondary fixing for all overhead rigged equipment in most professional venues and public spaces in the UK. Always attach a Doughty Safety Bond rated to at least the weight of the fixture or bar being suspended, in addition to the primary fixing provided by the Doughty Gravlock Couplers.

You may also like

4.60 ★ (224)
Verified
214
Verified Reviews