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I presume you are thinking this is a normal drill bit, it is not.
A normal drill bit:
1. Twists in the opposite direction
2. Has shorter twists
3. Has different relief angles
4. Clears chips differently
From the patent:
A normal drill bit:
1. Twists in the opposite direction
2. Has shorter twists
3. Has different relief angles
4. Clears chips differently
From the patent:
If bit 20 has a right hand twist, chips of wood will be drawn upward and blocked by the lower portion 17 of shaft 16. These chips will be packed in the circular cut being made in the workpiece 23 and may slow down the rate of cutting and they will prevent the free and easy removal of the disk cut from workpiece 23.
Therefore, as shown in FIGURE 2, cutting bit 20 has flutes 26 formed with a left hand twist so that wood chips 24 are urged downward and thrown clear and not packed against portion 17 of shaft 16. Since it is desirable to hold a pressure on the electric drill to urge shaft 16 against workpiece 23, the lower portion 17 of shaft 16 is forced against the top of workpiece 23 and would mar it unless the outer lower edges 25 of the lower portion 17 were curved smoothly upward. Thus the upward curved edge 25 of portion 17 cannot dig into the top of a workpiece being cut even when shaft 16 is unintentionally inclined away from a position perpendicular to workpiece 23.
FIGURE 4 shows a particularly satisfactory configuration for a cutting bit 20. The outer sides 27 of the flutes 26 rake backward at an angle from the cutting tips 28. This greatly assists in the side cutting action of bit 20.
