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Title: |
1905 Article-Pearl Square Auger Mfg. Co., Auger & Mortising Tool |
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Source: |
Engineering, V80, 18 Aug., 1905, pg. 225 |
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Insert Date: |
1/8/2021 12:37:56 PM |
We illustrate above a novel form of square auger for mortising. It is manufactured by the Pearl Square Auger Manufacturing Company, of New York, and is a combination of an ordinary circular auger bit, winch bores a round hole, and two side cutters, which form the square, all arranged on the same spindle. The round bit, seen at the end of the tool on the left-hand side of our engraving, is detachable, and can, if necessary, be screwed off the spindle. The square head which is formed on the end of the shell that carries the spindle is cut away on two opposite sides, at the extreme end, and in the recesses so made two cutters are placed, which revolve in planes parallel with each other, and their outer surfaces project very slightly above the surfaces of the square end of the casing or carrier. These Bide revolving-cutters gear with a small star-wheel on the spindle and revolve rather slower than the round bit.
As the side cutters leave between them a small portion of the wood which the round bit, owing to its circular form, has not removed, two small, fixed disc cutters, one on each side of the square head between the side cutters, remove this as the tool passes into the hole. These small discs are held in place by screws, one of which may be seen on the front face of the head in our engraving. The tail-end of the shell-piece forms a ball-bearing, which supports the spindle and takes the thrust. The bearing is held in place by a screw, shown in the illustration. Between the ball-bearing and the head the spindle has on it a helical band which removes the wood as it is cut away and throws it out through the opening in the side of the shell.
When the tool is used for mortising, it is essential that the wood is held firmly in place, and that the bit 1 runs truly and does not vibrate in the chuck or spindle of the machine that drives it. There are several ways by which the shell may be prevented from revolving while in use, one of them being the employment of a split bushing which fits tightly over the shell and is fixed by a clamp-nut. The bushing may have a light projecting arm which bears against some part of the machine which drives the bit. Special machines are made by the Pearl Square Auger Manufacturing Company for use with these bits when they are employed for mortising.
All parts of the bit we have described are accurately made, and are carefully hardened, so as to ensure durability. Additional particulars as to this auger can he obtained from Messrs. Thus. Thompson and Co., of 35, New Broad-street, London. |
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1905 Pearl Square Auger Mfg. Co., Auger & Mortising Tool
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