Wood router bit
AssigneeRoto Zip Tool Corporation
InventorRobert K. Kopras
Life of this patent
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Abstract
A router bit for laterally cutting through sheets of wood product, such as plywood and the like. The bit includes a shank portion adapted to be gripped in the chuck of a router, a fluted portion, and a tip. The fluted portion has two helical left-hand flutes. Each flute has a cutting edge and a web portion having a convex surface that extends rearwardly and immediately inwardly from the cutting edge, without a land, in a continuous curve. The flutes are formed by parabolic grinding. In one embodiment the tip is conical in shape and has two diametrically opposed tip flutes for cutting axially into a workpiece. In another embodiment the tip is flat and the bit is adapted only to cut laterally through the workpiece.
Claims9
A router bit comprising:
- on upper shank portion for being gripped by a chuck;
- a lower tip;
- and,
- two flutes extending helically in a left-hand spiral between said shank portion and said tip, each flute having a helically shaped cutting edge, each flute in cross-section forming a continuous S-shaped curve beginning at said cutting edge and extending immediately inwardly and rearwardly in a continuous convexly shaped curve leading to a continuous concavely shaped curve and ending at an opposed cutting edge, said S-shaped curves of said two flutes including no lands adjacent said cutting edges, the portions of said flutes which are convexly shaped in section forming a slight acute angle with respect to the axis of the bit extending downwardly to said cutting edge when viewed in axial profile.
Dependencies are inferred from the claim text.