Metal plate fixings

Finishes

Nail-on and screw-on fixings

The light gauge fixings are usually punched from galvanised steel sheets. This may be hot dip galvanised after manufacture for moderate-risk corrosion environments.

Stainless steel versions of these fixings are available for much of the range.

Stainless steel CT160 nail-on fixing

Photo: Courtesy MiTek.

Bolt-on fixings

Bolt-on fixings are usually manufactured from black steel and hot dip galvanised after manufacture. Stainless steel versions of these fixings are available for much of the range.

Toothed metal plates

The grasshopper-type tooth plates (Tylok and Pryda Knuckle nailplates) are only available manufactured from galvanised steel sheets.They are unsuitable for external applications.

Truss connector plates are usually punched from galvanised steel sheets, although stainless steel is available for corrosive internal environments. Stainless steel plates are unsuitable for use over swimming pools or external applications.

Lengths & sizes

Refer to the suppliers’ websites for the range of products available.

Components required outside the usual range available may be custom manufactured by engineering workshops.

Detailed manufacturing drawings are required for custom manufacturing and the cost of production will be higher than for standard products: Examples of the range of fixings available:

Photo: Courtesy MiTek.

Vendors Database

Application

Refer to the sections Nails, Screws, Bolt-on fixings under Finishes.

Truss connector plates are pressed into the timber using hydraulic or pneumatic presses.

The grasshopper-type tooth plates (MiTek Tylok or Pryda Knuckle nailplates) are carefully struck with a hammer to drive the teeth into the timber.

Uses

Typically, these fixings are used for residential house construction, but may also be used for commercial timber construction.

The visual impact of these fixings is often not ideal, however, they are usually hidden in roof, floor or wall spaces so this is not an issue.

There are ways of expressing the structure and still having it be aesthetically attractive, for example, by using bolted connector plates on a timber truss.

Specification

These products should be specified referring to the brand name, specific product and indicate the fixings to be used, for example: “use Lumberlok 47 x 190 joist hanger fully nailed” or “use Bowmac B176 with 4M12 bolts”.

Screwed and nailed on roof truss to wall fixing

Photo: Courtesy MiTek

Performance/Design

Nail-, screw- and bolt-on fixings

Manufacturers of these fixings have tested them extensively and publish loadings for most.

Some fixings, such as the bolt-on brackets, do not have loadings published because the load capacity depends on the application.

In these cases, designers should use the procedures from the New Zealand Timber Structures Standard NZS 3603.

Design method examples are also published by manufacturers.

Toothed truss connector plates

The design of timber trusses using toothed connector plates is undertaken by the truss fabricator utilising software provided by the truss plate manufacturer.

This is a specialised process requiring in-depth knowledge and training on the use of the software. As a result, the software is not available to the wider community.