The Technique of FURNITURE MAKING

PORTABLE PLANERS

These have only a limited use for the furniture - maker who, unlike the joiner and builder work­ing out on site, has constant access to a floor- mounted machine. On occasion, however, the surface planer may not be wide enough, and then the portable is extremely useful for these extra wide boards or table tops, even though, for final accuracy, a hand plane will be needed.

It is also useful for rebating if for any reason this cannot be undertaken on either the spindle moulder or surface planer. At the cost of little more than a large hand plane, it is, therefore, a useful addition to the workshop equipment.

83 Portable planer upended in purpose-made table for use as small bench planer

82 Planer upended to show cutter block and replaceable knives

HIGH-SPEED ROUTERS

These have power-driven vertical spindles on which the appropriate cutters are mounted and fed down to the work, while some models have an adjustable side swing movement enabling the width of cut to be increased or extended without moving the router-fence or changing the cutters. Usually these tools rely on speed rather than power output, therefore the depth of cut obtainable at any one setting is fairly small, but the degree of finish is quite high. Many models are available from fractional up to 21/2 hp (1.864 kW) with cutting speeds up to 27,000 rpm for the lightweight models, and a range of cutters for straight-line and circular grooving, moulding, veining, dovetail cutting, rebating, slot cutting, edge trimming, etc. The router itself with double handles can be moved freely in any lateral direction, but a range of guides for straight and circular cuts, trammel - points for circles and bases for working against templates give the tool wide versatility. It can also be mounted horizontally, or turned over to act as a fixed spindle-moulder, while various dovetail guides and templates will allow box - locking, carcass - and drawer dovetailing up to 25 in (635 mm) in width. Particular care should be exercised in choosing one of these machines and the nature of the work for which it will be

87 Variable speed lightweight electronic router

used fairly assessed, for while the lightweight models have 1/4 hp (0.186 kW) motors and a net weight of about 31/4 lb (1.475 kg) only, the heaviest models weigh up to 26 lb (11.793 kg), all of which has to be lifted and guided on to the work by one pair of hands. There is, of course, no kick or side thrust with a good machine, but even so the heavy models do require a certain amount of effort to guide them through heavy cuts, and often the lightweight model is a more practical proposition.

Properly chosen, in good working order and with a range of cutters, it is, however, an outstandingly versatile machine in the hands of a capable operator. The cutters themselves can be purchased to fixed specifications, but some makers quote for 'specials'. Usually both high­speed and tungsten-carbide cutters are obtainable, the latter much more expensive but lasting very much longer in materials bonded with, or composed of, synthetic-resin in any form. It is often more satisfactory to send the cutters back to the suppliers for regrinding, otherwise the critical profile may be lost, but some makers supply a bit - and cutter-sharpener which uses the machine itself to grind its own cutters. Typical operations performed by these machines are illustrated in Figure 90 and all manufacturers issue fully descriptive literature covering the entire scope.

It is sometimes advisable to purchase a plunging router as it is much simpler and safer in use for some jobs, and they are now very inexpensive. However, one of the dis­advantages of the standard portable router, plunging or otherwise, is that the constant high speed and accompanying high pitched whine can be distracting when undertaking delicate operations, and also renders the workshop rather unpleasant for any other occupants. A recent development to alleviate this is the variable speed electronic router, the 96E by Elu. It has five variable speed settings from 8000 to 24,000 revs, enabling very delicate work to be undertaken gently and surprisingly quietly. In addition, the electronic control prevents drop off of speed under load and also allows for a gentle build up of speed on each setting. This slower speed at the start of each cut allows for a more gradual entry of the cutter and avoids the snatching associated with high speed. The extra cost of the electronic version is soon recouped as the life of the bearings and motor is considerably extended, as for much of the time and for many operations the router can be running at quite low speeds. (In 1985 I re­equipped my workshop with the latest model, and with four people using the same workspace it has made for pleasanter working conditions for all concerned.)