COMPASS RABBET PLANE
Working wood with hand tools raises the possibility of approaching a task in different ways. Take cutting a rabbet, perhaps to make a corner joint or accommodate a drop-in lid.
Depending on the scale of the work, the rabbet might be roughed out with an axe and surfaces pared smooth with a slick, by making perpendicular cuts with a tenon saw, using a cutting gauge or even a scratch – a small scraper worked back and forth. But the yacht joiner, for whom rabbeting was a routine operation, would normally use a rabbet plane.
Even the simplest rabbet plane consisting of stock, iron and wedge is more sophisticated than it looks. The iron, full-width so as to cut a true right-angled corner and bevelled on the side to minimise friction, is also skewed to impart a clean shearing cut while generating sideways pressure which helps keep the plane tight against the shoulder. Normally a batten tacked temporarily to the work guides the plane until the shoulder is established but still the worker must hold the plane perfectly upright or the rabbet will develop a sloping floor. The more complex side fillister has an adjustable fence to set the rabbet’s width, a stop to limit depth and a chisel-edged ‘tooth’ for severing surface fibres in advance of the iron. Neither plane, however, can cut the concave rabbets required for arched panels or fancy coachroof glazing. This is the work of the compass rabbet plane.
As its name suggests, this plane is a hybrid of compass and rebate planes combining a radiused sole with skewed full-width iron. Again, the plane is guided by a batten, this time starting at the mid-point of the rabbet and steadily working outwards until the deepening shoulder lends support. Almost inevitably the floor of the rabbet finishes smoother at one end than the other because at the mid-point the iron transitions from working downhill with the grain to working uphill against it.
Compass rabbet planes were long ago made obsolete by routers which zip through this and countless other profiles in the blink of an electron, albeit while kicking up a dust storm. Still, the old woodies are worth knowing if only for the whisper of their shavings spiralling to the workshop floor.
NEXT MONTH: Butt gauge