US996612A - Auger-bit. - Google Patents

Description

. CALDWELL.

, AUGER BIT. APPLICATION FILED JUNE 24, 1908.

Patented July 4, 1911.

COLUMPIA'PLANDGRAPH C0., WASHINGTON. D. C.

pin s JOHN WILLIAM r arr CALDWELL, OF TORONTO, ONTARIO, CANADA.

AUGER-BIT.

Application filed June 24, 1908. Serial No. 440,177.

To all whom it may concern:

Be it known that 1, J OHN WILLIAM CALD- WELL, a subject of the King of Great Britain, of the city of Toronto, in the county of York, in the Province of Ontario, in the Dominion of Canada, have invented certain new and useful Improvements in Auger- Bits, of which the following is a specification.

The invention relates to improvements in auger bits as described in the following specification and illustrated in the accompanying drawings that form part of the same.

The invention consists essentially in the novel formation of the bit, whereby the spiral channels form free passages for the chips, said channels in cross section presenting a flat surface of greater width than the chi The objects of the invention are to obviate the difficulties experienced by the choking of bits, to devise a' bit which may be sharpened to the extent of the length of the spiral, to insure the proper feeding of the bit, and generally to facilitate the boring of holes in wood or like material.

In the drawing Figure 1 is a perspective view of one form of my bit broken intermediate of its length and showing the formation and arrangement of the side flanges, and also showing a chip resting in the channel formed in the spiral portion. Fig. 2 is a perspective View of the bit shown in Fig. 1 turned slightly from the posit-ion shown in Fig. l and showing the cutting edges and lead screw. Fig. 3 is a cross section through the bit shown in Figs. 1 and 2. Fig. 1 is a perspective View of a slightly modified form of my bit. Fig. 5 is a cross section through the bit shown in Fig. 4:.

Like numerals of reference indicate corresponding parts in each figure.

Referring to the 8 are the side cutters extending downwardly from the cutters 7 and formed by the side flanges 4 and 5 having the lower and front edges rounded and sharpened to cut into the wood.

9 is the lead screw centrally arranged and extending downwardly from the spiral l and having a core 10 tapering to a point.

11 are the spiral flanges of the lead screw extending outwardly from the core 10 and formed with their under surfaces beveled upwardly and inwardly and presenting downwardly extending cutting edges and terminating in a pair of downwardly sloping chisel points 12 extending beyond the point of the cone-shaped core 10.

The flanges or threads of the lead screw are formed with the same angle of incline as the spiral 1. The incline of both lead screw and bit may be varied in various bits to suit the kind of wood in which they are to be used, that is to say, bits to be used in soft wood may be fed quicker than if used in hardwood, and a steeper inclined lead screw consequently used in the soft wood, or on small sizes of bits or augers.

On inserting the bit into a piece of wood, the cutting points 12 at the end of the flanges ll-cut into the wood and as the bit is turned, the upper sloping side of the flanges 11 draw the bit downwardly forcing the cutters 8 into the wood. As the bit is drawn into the wood by the lead screw, the cutters 7 are brought into contact with the upper surface and cut away the chip. The width of the chip cut is of course only half the diameter of the bit, and as the flatsurface of the spiral 1 is of greater width than half the diameter, the chip will follow the spiral quite freely and not bind between the wall of the hole and the center of the bit, nor between the succeeding spirals, or flanges of the bit.

In Fig. 1, 1 have shown a chip resting in the spiral channel showing that there is considerable clearance between the outer edge of the chip and the outer side of the bit. This formation of the spiral allows the drawings 1 15 the spiral of the bit formed in cross section of the body 2 forming a web with parallel straight faces 3 and connecting the laterally extending flanges 4: and 5 at the side extremities, said flanges projecting from opposite faces of the chips to foll0w the spiral Straight from the body respectively and stiffening the same, cutting edge wlthout be1ng impeded in any said web and flanges forming a pair of spiral manner and through the pecullar formation of the lead screw the bit is drawn into the wood and does not require any end pressure.

In the form shown in Figs. 4 and 5 the side flanges 13 and 14 extend from each side of the body 2, so that there is a flanged channels 6 of greater width than half the diameter of the bit and extending throughout the length of said spiral. 7 are the cutting edges formed at the lower end of said spiral 1.

edge at each side of the upper surface. The object of this arrangement is to provide a double side cutter, that is to say, the side cutting edge 15 extends above and below the horizontally sharpened edge 16 of the web portion.

Either form of the bit may be sharpened from time to time as desired by filling the under beveled surface of the spiral l and sharpening the terminal edge of the side flanges. In the sharpening operation the central portion of the web is not cut away, but forms a continuation of the flanges 11 and as the said flanges are arranged at the same incline as the spiral 1 they will continue to follow the central core as long as the bit is sharpened. It will thus be seen that the bit may be sharpened until the spiral is worn short and the cutting edges will always remain in the same relative position and will also always allow sufficient clearance for the chip both close to the cutters and farther up the spiral;

It will be seen from this description that a bit formed as described has many advantages, as no bits at present known, as far as am aware, have suflicient space between the center portion and the outer side to allow the chip to pass from the cutter without crowding between the center and the side of the nole, in other words, the space is usually less than half the diameter of the bit, and as the clip cut is half the diameter of the hole, choking and waste of energy must occur. Further the forms of bits at present known can only be sharpened a few times until the cutters are worn away, when the bit has to be discarded, whereas in the present invention the bit is so formed that it may be sharpened until the whole bit is used up.

, in the Dominion The form of bit as herein described is equally adaptable for use in gimlets and small and large bits for various classes of work.

WV hat I claim as my invention is 1. An auger bit, comprising, a spiral body portion having a cross sectional shape showing parallel straight faces, said straight faces presenting channels of greater width than half the diameter of the bit.

2. An. auger bit, comprising, a spiralbody portion having a cross sectional shape showing parallel straight faces, said straight faces presenting channels of greater width than half the diameter of the bit, said body portion terminating in cutting edges to each side of the central lead screw and having flanges forming side cutters at the bottom end.

3. An auger bit, comprising, a spiral body portion having a cross sectional shape showing parallel straight faces, said straight faces presenting channels of greater width than half the diameter of the bit, said body portion terminating in cutting edges to each side of the central lead screw and having flanges forming side cutters at the bottom end, said side flanges in cross section appearing as extending laterally from said parallel straightfaces at each end and forming guiding shoulders for the chips in their travel along said channels.

Signed at the city of Toronto in the county of York in the Province of Ontario, of Canada this 16th day of June 1908.

JOHN WILLIAM CALDWELL.

WVitnesses H. DENNIsoN, WM. C. Mum.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C.

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