The Handyman's Book of Tools, Materials, and Processes Employed in Woodworking. Paul N. Hasluck
to some extent superseding the grindstone, the other for finishing the edge. In using the oilstone, first put a few drops of good oil upon the stone, and grasp the iron as in Fig. 196; the right hand is at the top, and the thumb and fourth finger pass under. Place the whole of the fingers of the left hand upon the iron, with the thumb at the back, as seen. Now put the cutting edge (previously ground to a bevel) upon the stone in an oblique direction, as shown in Fig. 196, bearing in mind the previous remarks on the necessary inclination. The iron should now be rubbed up and down the stone, pressing it down with both hands. If the edge had been examined before placing it upon the stone, it would have been found to show a fine white line. The object of sharpening is to remove this, which must, be done by rubbing on an oilstone. Having accomplished this, turn the iron face down upon the stone, and rub it lightly a few times (see Fig. 197). The iron should now have the appearances indicated by Fig. 198. If the face of the iron has not been kept perfectly flat, it would appear as Fig. 199, and would be of no use as a cutting iron. If the iron has been rubbed too long, a wire edge will appear and utterly spoil the cutting properties of the iron unless removed. This may readily be done by rubbing the iron alternately upon each side until the wire edge falls off. When the iron is judged to be sufficiently sharp, it should be cleaned, whetted on the left hand, and its edge tried for keenness. Some try the edge by passing the thumb gently across it, but its sharpness may be judged by looking directly at it. In a sharp tool the edge is not visible to the naked eye, while, if the iron should be blunt, the edge will be plainly perceptible as a bright line.
Fig. 195.—Plane Iron on Oilstone.
Fig. 196.—Sharpening Plane Iron.
Fig. 197.—Finishing Plane Iron on Oilstone.
Fig. 198.—Properly Sharpened Plane Iron.
Fig. 199.—Badly Sharpened Plane Iron.
Fig. 200.—Fully Rounded Plane Iron.
Fig. 201.—Slightly Rounded plane Iron.
EDGES OF PLANE CUTTING IRONS.
The edge of a cutting iron should be ground and sharpened to suit the tool in which it is to be used. If this is not done, the plane marks will be visible when the work is finished especially with polished or varnished surfaces. For a single-iron jack plane the edge should be rounded as in Fig. 200; for an ordinary jack plane the iron should be slightly rounded, as in Fig. 201; while for smoothing, panel, and trying planes the edge should be straight, but with just the corners rounded slightly to prevent their marking the work, as shown in Fig. 202. Trying planes, shooting planes, as well as rebate planes, badger jack planes, and rebating jack planes, should be sharpened with the edge straight. When a smoothing or panel plane is sharpened to the proper shape, and a board skilfully planed with it, no ridges will be perceptible to the touch if the hand is passed across it from side to side.
Fig. 202.—Plane Iron with Rounded Corners.
Fig. 203.—Plane Irons with Thin Cutter Between.
DEFECTIVE BACK IRONS IN PLANES.
If a plane does not work properly the fault often may be with the back iron. If the back iron does not fit perfectly close across the full width of the plane, the shavings get between it and the cutting iron and clog the mouth of the plane. The remedy is to fit the edge of the back iron to the face of the cutting iron. This may be done either with a file or by bending it over a piece of round iron with a hammer. A defect often found in back irons is that of slipping over the edge of the cutting iron when the screw is tightened to hold the two together, thus destroying the edge. This sometimes may be remedied by roughing the top end of the back iron where it fits on the top of the cutting iron, by placing it on a flat file and then hammering it; or the screw may be tightened with the back iron some distance back from the edge, and afterwards gently hammered to its proper position.
Fig. 204.—Steel Cutter for Improved Plane Iron.
IMPROVEMENTS IN PLANE CUTTING IRONS.
Much time is lost in grinding and sharpening plane irons of the thickness to which they are made at the present time. It is only the thin steel face of the iron that requires a keen edge; yet to obtain this a waste of time is incurred, owing to the amount of metal that must be removed at the back of the edge. Now if a thin steel cutter could be introduced to place between the two irons, it would do away with the grindstone altogether for sharpening planes. This idea is not by any means new, and it has been practically carried out, both with hand and machine tools, with marked success. Fig. 203 shows this principle applied to an ordinary plane iron; Fig. 203 shows the back and fore iron, between the two being the thin steel cutter, shown separately by Fig. 204. Cutters of this description could be produced at half the cost of ordinary plane irons, if made in any quantity. Grinding a plane iron is a dirty job, even under the most favourable circumstances, and it is thought that a cutter that does away with it is bound to meet with success.
Fig. 205.—Grinding Gouge.
Fig. 206.—Grinding Gouge.
Fig. 207.—Sharpening Gouge on Oilstone.
Fig. 208.—Sharpening Gouge with Oilstone Slip.