Planing big slabs
My friend Charlie just dropped off a couple nice big slabs of walnut. The original intention was to cut them into heavy veneer and squares for legs. But one of them was was just dead straight and I immediately knew that I had something else in mind for this particular piece.
Big slabs seem to pose problems for many woodworkers. They’re hard to move around. They’re usually too heavy or too large to run through planers and sanders. But for the folks that understand how to “walk” a board and use handplanes, big slabs can be handled with relative ease.
The first thing is to get one side in plane. This becomes the datum, the surface from which all other dimensions are taken. Using a set of winding sticks, the rough surface is checked for wind, cup or bow and imperfections in sawing. Those areas are marked.
Rough planing is done with a long plane with substantial camber in the iron. My favorite plane for this part of the process is a 20″ wooden foreplane. Planing is usually done at about 45 degrees to the grain direction of the workpiece, although many times I find that I’m planing cross grain. The heavy camber of the iron allows for large shavings to be taken without an irordinate amount of edge tearout.
After the datum surface is in plane, a smooth plane is used to remove the wide, shallow “scallops” left by the foreplane and render the datum dead flat. Then the slab is flipped and the required thickness is measured and marked with a cutting or panel gauge. Again the foreplane if used to produce a plane second surface, parallel to the datum. If a large amount of material must be removed from certain areas, a scrub plane can be used. The scrub plane has a narrower iron with greater camber than the foreplane. This enables the plane to take very thick, narrow shavings and speeds the work of stock removal. The foreplane can then be used to remove the deep grooves created by the scrub plane.
Trueness in length can be checked by a straightedge or the winding sticks can be laid flat at both ends of the slab and a line can be stretched across them. Any variance will be quickly determined by simply measuring at points along the line to the surface of the slab. And remember that the human eye is a very precise instrument.
Only time will tell what this slab will become.