The Technique of FURNITURE MAKING

Miscellaneous planes

Several other types of plane with occasional uses exist, some of which can be purchased, though others will have to be made. Figure 59:1 illustrates the cooper’s stoup-plane with sole rounded in both length and width, and with the iron curved as shown; it is useful for dishing fairly large surfaces such as stool seats, etc. It can be converted from a standard wooden smooth - or coffin-plane. Another good tool is the Jarvis spoke shave-plane (59:2) used by wheelwrights for rounding spokes, with metal spokeshave-type flat iron ground to a hollow, and knock-in wooden wedge. Figure 59:3 shows the wooden scrub-, rougher - or Bismark-pane which is still manufactured, and is invaluable for knocking off the rough preparatory to either hand - or machine-surfacing. Also available is

the traditional wooden skew rebate-plane with single iron set at an angle to give a shearing cut. Figure 59:4 shows the standard toothing-plane (see Veneering, etc. Chapter 32) in which a series of corrugations in the iron scores the surface of the wood. It is used for keying the groundwork preparatory to veneering with hide glue, and for levelling bumpy veneers, etc. Mention must also be made of the incomparable Norris planes, smooth-, jack - and low-angled mitre - or piano-finishers' plane. They are no longer manufactured, but second-hand planes in good condition command high prices and the writer counts them among his most prized possessions, not for any sentimental reason but because they happen to do their job extremely well. For the final surfacing of really difficult woods—ebony, East Indian satinwood, etc.— they are excellent, and no doubt the secret lies in the extra stout iron of first-class steel and the heavy and sturdy body which always seems to hug the wood. Before quantity production became the rule and not the exception the old craftsmen always treasured their extra long and heavy wood jointing-planes, and several of the smaller bench-planes they made for themselves from rough gunmetal castings; nor is there any reason why the enthusiast with some slight engineering skill should not do the same. Single and double plane-irons in all sizes are still freely available and can be ground to fit. Beech and rosewood are excellent for plane-making; the wood should not be oiled, as is sometimes advocated, but coated with shellac varnish to seal the pores.

Cutting angles

All bench-planes for general levelling, i. e. jointer-, try-, fore-, jack - and smooth-planes, have double irons (Figure 60:1) composed of the cutting iron proper and the cap-iron whose function it is to stiffen the cutting edge and break up the shaving as it is raised so that, robbed of its stiffness, it does not tend to run ahead of the cut in a series of small splits in the surface of the wood. The closer this cap-iron is to the cutting edge the sooner the shaving is bent over and broken, and therefore fine cuts or difficult timbers require a close-set cap-iron and a narrow mouth which, in the case of metal
irons. Figure 60 illustrates the various pitches: 60:1 for bench-planes fitted with cap-irons whose function it is to support the cutting edge and break up the chip as it rises; 60:2 shoulder rabbet - and block-planes with bevel uppermost; 60:3 moulding-planes and 60:4 the toothing - plane. All these pitches are empirical, i. e. the result of long experience and not scientific enquiry. Whereas a good deal of research has been done into cutting angles for machine- cutters, it is a little surprising that manu­facturers of hand-tools have not experimented with variable pitch planes, in which the cutting angle can be altered for difficult woods, inter­locked grain, etc.

60 Cutting angles: planes

bench-planes, is easily adjustable. Practical experience will give the best setting of the cap - iron, which may vary from a hair's breadth for the final surfacing of difficult timbers to 1/16 in (1.5 mm) for the first rough levelling. This use of the cap-iron means that the grinding bevel of the cutting iron must be underneath, therefore the cutting angle is dependent on the pitch or angle of the iron in the plane, irrespective of the grinding angle. Usually a compromise angle of 45° is used for bench-planes, for raising the angle gives more of a scraping action and lowering it more of a slicing cut.

In the case of metal shoulder rabbet - and block-planes which are only used for trimming and final levelling, often on end grain, the mouth must be kept as small as possible and the iron supported right up to the cutting edge to prevent clattering. As there is no room for a cap-iron the iron is reversed bevel uppermost, which in turn raises the cutting angle, therefore the pitch is lowered, giving an effective angle of about 50° which is about right for a scraping cut on end grain. Moulding-planes also cannot be fitted with a cap-iron even though the bevel is underneath, and to prevent any tearing out of the grain the angle is raised to about 55°. Toothing-planes which merely score the surface of the wood are set at an angle a little short of upright. The remarks regarding the advisability of preserving one long bevel to cutting edges advocated for chisels equally apply to plane-