Timber Connectors

Timber connectors are building accessories, specially designed to provide enhanced bolt performance in timber to timber and timber to steel connections. These timber connectors are manufactured from high quality pre-galvanised steel or hot rolled mild steel, and are also available in stainless steel for extended durability and enhanced strength. Shear Plate and Split Rings Connectors are accompanied with the adequate grooving and dapping tools, for eased installation. All products are manufactured in accordance with the BS EN 912:2000 of the Building Regulations.

A structure is a constructed assembly of joints separated by members. The joint is generally the critical factor in the design of the structure in timber engineering. The strength of the connectors in the joint will normally dictate the strength of the structure; their stiffness will greatly influence its overall behaviour and member sizes will generally be determined by the numbers and physical characteristics of the connector rather than by the strength requirements of the member material.

Bolted joints can be strengthened by timber connectors in the joint surface.

Split ring connector joints  

• For timber to timber connections,
• Installed in pre-cut grooves
  

Shear plate connector joints

• For timber to timber or steel,
• Installed in pre-cut grooves
  

Toothed-plate connector joints

• For timber to timber or steel, 
• Pressed into the timber
  

Timber connectors are load transferring devices which rely on bolts or lag screws to restrain the joint assembly. Timber connectors are more efficient structurally than bolts or lag screws used alone, because they enlarge the wood area over which a load is distributed. The bolt clamps the joint together so that the connector acts effectively. Timber connectors are used mainly to transfer loads in heavy timber or Glulam members in roof trusses.

Tooth Plate Timber Connectors (single and double sided) for improved bolt performance in timber, available in pre-galvanised and stainless steel. The connector's teeth must be embedded fully into the timber contact surface in order to achieve their design capacity.

Single and double sided Tooth Plate Connectors are for improving bolt performance in timber. They are easily installed devices for improving the efficiency of timber structures. They increase the joint strength, reduce the size of members required for a given load and simplify fabrication and erection. The use of toothed connectors in timber structures can make it possible to develop the full allowable load of the members connected and in some circumstances, make a joint stronger than the members themselves.

Fixing Instructions

• Drill holes in timber 1.5mm larger than diameter of bolt.
• Assemble components and tighten nut to embed connector. If timber is dense or there are more than three connectors on the same bolt use special high-tensile steel bolt and 6mm large washers (for embedding only).
• After tightening remove special bolt and 6mm washers and insert permanent bolt and 3mm washers.
• For demountable structures use two single-sided connectors back-to-back.
• Tightening nut embeds connector.
• In a completed joint, there may be a space between adjacent members equal to the thickness of the centre plate of the connector.
• It is important that the teeth should be fully embedded,
• The nuts should not  be over-tightened to such an extent that the washers become cupped and embed themselves in the timber.
  

Shear Plate Timber Connectors are designed for timber to timber or timber to steel connections, produced from hot rolled steel and stainless steel, accompanied with proper grooving and dapping tools.

Shear plate timber connectors are round, malleable iron discs that are inserted in precut grooves and are completely embedded in the timber when in position, being flush with the surface of the timber. They are also known as timber washers. Shear plates are intended primarily for wood-to-steel connections or for wood-to-wood connections in demountable structures when used in pairs. Shear plates provide greater load-carrying capacity in shear than can be achieved by a bolt alone. Shear plate timber connectors are used for increasing the strength of the joints in timber construction and reduce the number of bolts required.

Shear plates are used where demountability is desired in wood-to-wood applications. They are used to attach columns to footings through steel straps, to fasten of steel gusset plates to wood members, and to connect steel heel straps and splice plates in trusses, glued laminated arches, and beams. 

Fixing instructions

• In order to properly groove the timber, a bolt hole must first be drilled through the wood.
• Use the pilot bit to properly align the cutter head so that it centres itself on the pre-drilled bolt hole. This will ensure that the grooves created for the interior and exterior lips on the shear plate will be concentric to the bolt hole.
• The face of the shear plate should be flush with the surface of the timber.

Split Ring Timber Connectors for timber to timber joints connections are produced from hot rolled steel and stainless steel, but also available as Bright Zinc Plated and Heavy Duty Galvanised, accompanied with proper grooving tools. The split ring has bevelled inside and outside face, which makes it easier to insert in the pre-cut grooves and also gives greater load capacity.

The Ring is split across at one point, the split being in the form of a tongue and groove. The purpose of the tongue and groove is to provide for possible expansion or contraction of the timber. When the ring is embedded in the timber, it can expand or contract with the wood, and thus at all times forms a tight and rigid connection. The ring is sunk into the groove of one of the two facing members, and the other half into the groove of the other member, so that when the two members are joined face to face, the ring is wholly embedded between them. The connecting-through bolt is relieved of this stress by the embedded split ring. The bolt principally serves the purpose of holding two members together. A special tool is available for cutting the grooves in the timber.

Fixing instructions

• Drill holes in timber 1.5mm larger than diameter of bolt.
• Make circular grooves half of the depth of the ring parallel to its axis are cut in the contacting surfaces of the timbers, using special grooving tools with a pilot shank which centres in the bolt hole already bored.
• The Split-Ring is then placed in the groove in one timber, the other timber fitted over it, and the joint is drawn tightly together with the bolt which remains in the joint.

Dapping Tools

Dapping tools cut special grooves, called daps in timber and are essential for the installation of shear plate timber connectors. The daps created by this tool match the size and shape of the shear plates. Dapping tools can be used with either a drill press or with a heavy duty portable drill. Each dapping tool consists of a cutter head with blades and a pilot bit.

Fixing instructions

• Assemble the pilot bit into the cutter head and tighten it with an Allen wrench.
• Set screws on the face of the dapping tool can be adjusted to increase or decrease the depth of the grooves.
• Drill a bolt hole through the wood. Insert the dapping tool into a drill press or into a portable drill.
• Use the pilot bit to properly align the cutter head so that it centers itself on the pre-drilled bolt hole and drill until the correct depth is achieved.
• The face of the shear plate should be flush with the surface of the timber.