Hammer tap quickly reveals log secrets

By RICHARD WOOD

Carter Holt Harvey will market a device internationally that can be used to sort logs by hitting them with a hammer.

The Director HM200 identifies the characteristics of the log by analysing the sound of the hammer measured at the end of the log.

It has been patented and developed over two years and is in everyday use within the firm in identifying log stiffness.

Carter Holt claims profit increases of up to 10 per cent in processing high-value logs.

Spokesman John Prasad said sorting logs used to be a matter of applying an experienced eye.

By segregating trees into logs that could and could not be used for structural purposes, wastage was minimised, he said.

The Director HM200 will be marketed by the company's Fibre-Gen division in North America and Australia, but will not be sold in New Zealand.

The initial run is 100 units and the potential market in log yards and forest skid sites has initially been estimated at 1000 units valued at between $10,000 and $12,000 each.

The original product, called "Hitman", was researched and created by Crown research institute Industrial Research, but was not suitable for production and export due to weight and a lack of robustness.

Over the past 12 months the product has been redesigned from scratch by Christchurch high-tech design firm InFact and is being manufactured by electronics contractor GPC.

It uses frequency to generate a resonance profile for each log.

This can be used for the initial sorting and can also be stored in a database.

A significant design issue was in making the device resistant to water, grease, resins and spray paint.