Time to Start Thinking “Radially”…
Timber milling procedures have changed little over the centuries, with quarter sawn and back sawn cutting patterns as entrenched as death and taxes – but a Victorian company is winning favour with “radial” sawing…
Most hardwood mills in Australia produce lengths of timber cut in either quarter or back sawn configurations. Quarter sawn cuts produce plank lengths with the side edges facing the core and outer circumference of the log respectively; back sawn timber is cut with the flat surface (rather than the edge) of each length aligned along the same inner/outer plane.
An ancient alternative – and one with the potential to make efficient use of smaller-diameter logs – is the radial cut system based on early splitting patterns: think of a birthday cake sliced into equal wedges around an inner circular core, and you’ll have a good idea of the radial cut principles.
Radial Timber Sales in Melbourne is the sales arm of the milling company Radial Timber Australia, based in Yarram, Vic. The mill has been operating since the late 1980s and is the only mill of its type in the world. Each year the company handles about 2,500m3 of hardwood logs, about a quarter of which are sourced from plantations. The most common varieties are Silvertop Ash, Brown Stringy Bark, Yellow Stringy Bark, and Mountain Grey Gum.
Radial cut methodologies, according to the company’s Sales Manager Andrew McEvoy, have a broad range of advantages over conventional cuts, most notably in terms of timber length consistency and evenness, suitability to small log cuts, unique finish and minimal wastage.
“With the radial process you release the stresses evenly,” explains Andrew, adding that each cut length shows the full ring grain of the log. “This means that all the pieces are even and there is reduced warping and twisting.” Conventional cuts can also produce strong and even results, says Andrew, but these traditional cutting processes are most effective on larger-sized logs up to 600mm diameter or more. Radial cut timber, however, can be used on logs down to about 250mm diameter.
“This is extremely important,” says Andrew, “because the bigger logs are becoming harder to find. It’s getting to the point now where the wider 150–200mm flooring boards, the wide decking and the big feature beams just aren’t available unless they’re recycled.
“At the moment the big commercial operators might have 50–60% of their product coming from the larger 500–600mm logs, and only about 10% from logs of less than 400mm diameter, but what happens in five years’ time when the larger logs are only 20% of your resource, and smaller logs make up, say, 60%? We’re not saying radial sawing is a replacement for conventional sawing, but it is certainly a complementary technology because it can handle these smaller sizes.”
Radial Timber supplies are used for a variety of building materials, including weatherboards (both natural and square edge), decking timber (55mm and 80mm widths of 19mm depth), wide boards; and general dried and dressed shiplap cladding. Individual products of great interest to builders and architects include wedge panels, which have rebates cut into the base so lengths can be mated snugly with each other for strong and reliable wall cladding or fence panels. Products have been used in the construction of several major projects, including Taronga Zoo in Sydney; Moana Surf Life Saving Club, SA; Uluru National Park Cultural Centre, NT; Churchill Island Visitor Centre, Phillip Island, Vic; as well as an extensive range of private dwellings.
Not only is radially sawn timber beautiful and structurally strong, but it is also highly efficient. When used to create natural-edge weatherboard cladding, for instance, Andrew says the recovery rates are up to 75–80% of the log. Wedge panels recover 60–70% and boards for decking, shiplap and flooring up to 50–60%. As a unique business Radial Timber has had to develop much of its own technology, and refinements to the in-house-built saw machinery and business procedures are ongoing.
“Our attitude is that we have to think of the future and allow for the fact that natural growth forests are not going to be available forever. Ideally, it would be good to have our own hardwood plantations so we could grow our own trees, do our own cuts and harvests, and sell the timber ourselves.”
For more information visit www.radialtimber.com.
By John Power