Auger Drill Bit
An Auger drill bit has a specialized center that is optimized for drilling in wood with a hand brace. The specialized region consists of a tapered screw thread. The screw thread purpose is to screw into wood when the drill is turned on and pull together the bit into the wood.
There is no need to use any force or to push hard on the bit because the torque from turning the bit is more than adequate. This is the best scenario for a bit that is used for a hand tool.
The cutting edges remove a thickness that is proportional to the pitch of the central screw for each revolution of the bit. In order to remove the bit from the hole the rotation of the bit must be reversed. Simply put, the opposite direction of the initial bits motion must be employed.
So what separates the Auger Drill Bit from any other drill bit? The auger drill bit utilizes a long deep spiral flute that helps in the removal of chips and waste. The 2 most common auger bits used in hand braces are the Jennings and the Irwin.
The first auger bit, the Jennings, was founded and developed by Russell Jennings in the 19th century. The bit has a self feeding screw tip, 2 spurs and 2 radial cutting edges. What makes this bit unique is the double flute which starts from the cutting edges and extends up the shank of the bit. This is specifically designed for waste removal.
The Irwin also known as the solid-center auger bit is very similar to the Jennings. The only difference that distinguishes the 2 is that the Irwin has a smaller flute. The vestigal flute only extends about 12mm up the shank and then stops. The Jennings flute continues full length up the shank for waste removal as stated above. When referring to auger bits, the diameter of the bits is commonly expressed as a single number. An example of this is the number #4 represents 6mm or 4/16 or 1/4″.
The auger drill bit is best suited when you want to drill large diameter holes that are also deep. This bit functions with wood and man-made boards. This bit should only be used with a hand brace. This is because the pulling action of the bit makes it unsuitable for a power drill. So basically the best time to use an auger bit is when you want to cut a clean, deep and flat bottomed hole.
Form more information on Auger Drills check Sheet Metal Hole Saws
