Another burl found itself being flattened at the hands of the TWC at Ballarat last weekend. This one had quite a curvature, with over 1″ from edge to centre on the cut side.
For a thicknesser, this would be a nightmare. For the TWC this was a piece of cake.
You may be able to see the separate passes in the photo- this is because at the time of the photo, I was working on maximum material removal (4-5mm per pass, to the full width of the cutter). This means the grain on adjacent passes got cut in the opposite direction to the previous, resulting in a different reflective surface- you can see the passes, but it still feels flat.
The final pass is done with very little material removed 0.5mm depth of cut, and maximum 1/2 the cutter width max, so all the grain is pushed in the same direction.
Either way, a few passes with the ROS (random orbital sander) removes any minor irregularities.
The problem for the thicknesser is both the tortured grain – in all directions so tearout is likely. The cutter direction on a thicknesser makes this even more likely, with the cutter scooping the material up, out of the surface.
Secondly, stabilising a burl to pass through a thicknesser is also tricky. With drive rollers pushing down before and after the cutter, the chances of the burl shifting and getting a massive kickback from the thicknesser is pretty high.
On the Torque, the cutter direction is horizontal, the amount of material removed each pass can be minimal, and is not over the entire burl width simultaneously, and there are no feed rollers to potentially destabilise the burl during the cut.
Thicknessers obviously perform a very useful role, but when their idiosyncrasies work against you, the Torque Workcentre takes over!
Filed under: Manufactures and Suppliers, Techniques, Timber, Tools Tagged: Burl, Kickback, Surfacing, tearout, Thicknesser, Torque
