Part 8 (2/2)

7. _Bottom_.

8. _Mouth piece_.

9. _Eccentric plate_.

10. _k.n.o.b_.

[Footnote 6: See footnote p. 70]

The block-plane was devised for use with one hand, as when it is used by carpenters in planing pieces not readily taken to a vise or in planing with a bench-hook. Hence it is made small, 3-1/2” to 8” long, the clamp is rounded so as to act as a handle, and the cutter is lowered to an angle of about 20 to make the plane easy to grasp. The lower angle of the cutter makes it necessary that the bevel be on the upper side. Otherwise, to give clearance, the bevel would have to be made so long and so thin as to be weak. By putting the bevel up, the angle between the wood and the cutter is maintained practically as in the smooth-plane. Since the block-plane is intended chiefly for use on end grain, no cap is needed to break the shavings. The adjustable throat makes it possible to cut a very fine shaving. To facilitate the cutting action, several forms of block-planes with a very low angle are now made.

Where both hands are free to hold the plane, the block-plane has no advantage over a smooth-plane, even on end grain. Moreover, the cutter cannot be held so firmly in place as that of a smooth-plane, so that it requires constant adjustment. Hence it is not an easy tool for amateurs to handle. There is considerable lost motion in the adjusting nut, and the set-screw, which acts as a k.n.o.b, is likely to work loose and be lost. It is hardly to be recommended as a part of the equipment of the individual bench in school shops.

The piece to be planed with the block-plane may be held either in the vise, end up, or on a bench-hook, Fig. 109. In end planing in the vise, in order to avoid splintering the precaution should be taken to trim off a corner on the undressed edge, as directed on page 73, or else the planing must be done from both edges toward the center. The sliding cut is much easier than the straight cut, and hence there is a constant temptation to turn the plane at an angle perhaps at an expense of the flat surface desired.

[Ill.u.s.tration: Fig. 109. Using the Block-Plane and Bench-Hook.]

In using the bench-hook the piece to be block-planed is placed with the working edge against the block, with the end to be planed to the right and flush with the edge of the bench-hook, in which position it is held with the left hand. The block-plane, held in the right hand, is placed on its side on the bench facing toward the work. In planing, the left hand holds the work firmly against the block of the bench-hook, pressing it somewhat to the right against the plane. The right hand holds the side of the plane flat on the bench and presses it to the left against the bench-hook and work. Held in this position the plane is pushed forward and back until the end is smoothed.

Considerable practice is necessary to handle the block-plane well.

The _scrub-plane_ is a short plane in which the crown of the cutter, Fig. 110, is quite curved. It is used to reduce surfaces rapidly.

The _scratch-plane_, Fig. 111, has a toothed cutter which scratches fine lines along its course. It is used to roughen surfaces of hard wood which are to be glued together, for otherwise the glue would not adhere well. Some tropical woods are so hard that their surfaces can be reduced only by a scratch-plane. It is also useful in preparing the surface of a very cross-grained piece of wood which cannot be planed without chipping. By first scratching it carefully in all directions, it can then be sc.r.a.ped smooth. It is also called a _sc.r.a.per-plane_, because accompanying the plane is a sc.r.a.per which can be inserted in the same stock and inclined at any required angle. This plane-stock prevents the sc.r.a.per from unduly lowering some portions of the surface. See also veneer-sc.r.a.per, p. 91.

[Ill.u.s.tration: Fig. 110. Cutter of Scrub-Plane.]

[Ill.u.s.tration: Fig. 111. Scratch-Plane and Sc.r.a.per-Plane.]

[Ill.u.s.tration: Fig. 112. Rabbet-Plane.]

[Ill.u.s.tration: Fig. 113. Molding-Plane.]

The _rabbeting-_ or _rebating-plane_, Fig. 112, is designed for use in cutting out a rectangular recess, such as the rabbet on the back of the picture-frames. In line with the right hand corner of the cutter is a removable spur to score the wood so that the shaving which follows may be cut out clean and not torn out. With the addition of a guiding fence it is called a _filletster_. This may be used on either the right or left side. In the form shown in Fig. 112, there is also a depth gage.

In using this plane see that the corner of the cutter is in line with the sole, and that both it and the spur are sharp. Set the fence and the stop at the desired width and depth of the rabbet. At the first stroke the spur will score the width. This and every stroke should be taken as evenly and carefully as if it were the only one. In the effort to keep the fence pressed close to the side of the wood, the tendency is to tilt the plane over. This causes the very opposite effect from that desired, for the spur runs off diagonally, as in Fig.

114.

[Ill.u.s.tration: Fig. 114. Result of Careless use of Rabbet-Plane.]

If this happens stop planing at once, clean out the recess properly with a chisel and then proceed.

The _dado-plane_ is much like the rabbeting-plane, except that it is provided with two spurs, one at each side of the cutting edge, to score the wood before cutting.

The _molding-plane_, Fig. 113, as it name indicates, is for making moldings of various forms; as, quarter-round, half-round, ogee, etc.

[Ill.u.s.tration: Fig. 115. Tonguing-and-Grooving Plane.]

The _tonguing-and-grooving-plane_, Fig. 115, is for matching boards, i.e. making a tongue in one to fit into a groove in another. See Fig.

269, No. 72, p. 182.

The _circular-plane_, Fig. 116, has a flexible steel face which can be adjusted to any required arc, convex or concave, so that curved surfaces may be planed.

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