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UNITED STATES PATENT OFFICE
LEONARD BAILEY, OF BOSTON, MASSACHUSETTS.
Letters Patent No. 72,443, dated December 24, 1867.
IMPROVEMENT IN CARPENTERS' PLANES.
|TO AIL PERSONS TO WHOM THESE PRESENTS SHALL COME:
Be it known that I, LEONARD BAILEY, of Boston, in the county of Suffolk, and State of Massachusetts, have invented a new and useful Improvement in Bench-Planes; and I do hereby declare the same to be fully described in the following specification, and represented in the accompanying drawings, of which Figure I is a top view, and
Figure 2, a longitudinal section of a plane-iron and its cap-iron, and their holding-devices, such cap-iron being constructed in accordance with my improvement. Figure 3 is a longitudinal section of the plane-iron and cap-iron, as ordinarily constructed, that is to say, with one bend, a, only near the bearing-edge of the cap-iron.
My object is to use very thin steel plane-irons, and in so doing I find that they are liable to buckle under the pressure of the cap, which causes them to chatter, and makes them otherwise imperfect; and my invention consists in the providing of an auxiliary point of contact between 'the cap and plane-iron, and at the point where the plane-iron tends to buckle or rise from its bed or base, and thus have a pressure at that point in addition to that at the cutting-edge, which firmly holds this thin plane-iron to its bed.
The cap-iron, as commonly constructed, that is, as shown at D, in fig. 3, when applied to the plane-iron E, will rest thereon only at the extreme lower end of the cap-iron, and also at or very near. its upper end. There will be along angular space, b, between the two irons, when they are clamped together by the holding-devices which are represented in figs. 2 and 3, at A, B, and C, and consist of a screw) A, a bearing, B, and a cam-lever, 0, arranged in a manner well'known.
The difficulty experienced from the construction of the cap-iron with the single bend a, is, that it allows of vibration of the cap-iron and the plane-iron while in use, such vibration being productive of what joiners term "chattering," and consequent defective operation of the plane.
In carrying out my improvement, I make the cap-iron with an additional bend, I, (see figs. 2 and 3,) at a short distance back of its lower end or toe, or at a distance therefrom equal to about double the distance at which such lower edge or toe is to be from the main bend a, or the toe of the bearer B, the same being as shown in figs. 2 and I, so as to cause the cap-iron D' to bear on the plane-iron E'' in three places, or at the toe and auxiliary bend of the cap-iron, and along from such bend to the heel or upper end of the cap-iron. This construction or formation of the cap-iron D' completely obviates the difficulty above mentioned, and is a very valuable and useful improvement.
In all bench-planes the plane-iron must project slightly beyond its bed or bearing, the edge of the bed beyond which it projects serving as a fulcrum to the force of the pressure of the cap upon the extreme edge of the plane-iron. When thick plane-irons are used, their stiffness may resist the pressure of the cap sufficiently to pre- vent 'buckling or rising of the plane-iron from its bed; but in thin steel plane-irons which I use, the pressure of the cap upon the projecting portion of the plane-iron causes this portion to yield slightly, and of course produces buckling at some point behind, and generally close to the fulcrum. To prevent this buckling or rising, and still use the thin steel plane-irons, I put an extra bend in the cap, so that it shall have a point of impact with the thin steel at the place where .it tends, from the pressure on its projecting edge, and the fulcrum behind that edge, to risefrom its bed, and thus I effectually prevent "buckling" and "chattering," whilst I can avail myself of the economy of thin steel for the plane-irons.
What I claim as. my invention, and desire to secure by letters Patent in the adaptation of thin steel to the plane-irons of bench-planes, is
The auxiliary point of impact between the cap and the thin plane-iron, at the point or portion thereof where the thin steel tends to buckle under the pressure of the cap upon the projecting edge of the plane-iron, substantially in.the manner described.