The Technique of FURNITURE MAKING

GENERAL NOTE

It must always be remembered that wood­working machines, with their constantly varying loads as the cutters strike the hard and soft grain of wood, are gluttons for power, and that portable tools usually rely more on speed than power output or torque for their performance. They should, therefore, never be expected to undertake the heavier tasks which should rightly be given to the large fixed machines. Manufacturers give full and precise instructions and some issue their own handbooks on the techniques to be employed. They are also con­cerned to make their portable tools as safe as possible, but it is the rough usage to which the tools are often subjected which constitutes the danger, and no amount of foresight on the manufacturer's part can prevent a careless worker standing on a wet floor and trailing bare wires everywhere from electrocuting himself. Given correct treatment, with the wiring periodically checked, properly earthed or grounded, and the motor itself never taxed beyond its stated capacity, the average portable tool will give good service over many years, and become essential in the workshop.

CIRCULAR SAWS

Sometimes known as 'saw cats' or 'builders' saws', and available in both general and heavy duty models, with a range of saw diameters from 61/2 in (165 mm) to 10 in (254 mm)—the smallest size will cut slightly over 2 in (50 mm) thicknesses, and up to 3 1/2 in (89 mm) for the largest. As a rule all these saws are well balanced, fully adjustable for depth and any angle of cut up to 45°, with automatic retractable lower guard and fixed upper guard, splitting - or riving-knife and ripping fence. In spite of their somewhat fearsome aspect they are safe in use, as the blade is at all times covered, and overloading merely stalls the motor. A range of saw-blades is available: combination-saws for ripping and crosscutting; crosscut for fast, smooth crosscutting and there-

fore more suitable for plywood than the coarser cut combination-blade; planer-blades which give a very smooth cut and can be relied upon not to rag out the cross grain of ply or crumble particle board; flooring-blades designed for cutting through occasional nails but very suitable for resin-bonded chipboards etc., which quickly dull the edge of average saws; and a range of soft-metal cutting saws. Heavy gauge sheet-steel pedestal saw-tables or bench-stands can be obtained for these saws, but they can never have the accuracy of the orthodox table saw, and should, therefore, be regarded as a compromise solution only. Probably the chief uses for these saws in the furniture industry are the crosscutting of random plank and ripping up large sheets of plywood which cannot be handled on the normal table saw.