How are auger bits manufactured?

4th August 2021


	How are auger bits manufactured?


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			Auger bits are partly machine produced, and partly forged and ground by hand. As they are produced in a number of different patterns, this guide covers the basic manufacturing process for a standard Russell Jennings pattern auger bit.For more information on patterns, see: What are the different auger bit patterns?

			Step 1 – Forging the blank Steel bars are heated to a temperature of 900 degrees centigrade.

			One end of each bar is flattened with a pulsating power hammer to produce a long, thin strip of metal on the end of a cylindrical shank. For more information on the type of metal used, see: What are auger bits made of?

			Step 2 – Creating the flighting The blank is reheated, and clamped into a twisting machine, which creates the characteristic spiral shape of the auger.

			For the bit to work properly when complete, all of the twists in the spiral flighting must be uniform. To make sure this is the case, the bit is reheated and repeatedly crimped in a toothed vice. This keeps the diameter of the tool consistent.

			Step 3 – Shaping the guide screw Once the flighting is complete, the tip of the bit is reheated, then slammed under a drop hammer that forces the end point into a die.

			Waste material created by this process is clipped away from the end of the bit with a clip press, leaving behind the basic shape of the guide screw.

			Thread is ground into the guide screw on a ridged grinding wheel.

			Step 4 – Preparing the shank The shank of the drill is then cut down to the right size on a lathe.

			Step 5 – Heat treating Now that it is the right basic shape, the auger bit is reheated in a forge before being plunged into cold oil. The rapid cooling alters its molecular structure and causes it to harden.

			Step 6 – Grinding and sharpening In its hardened state, the auger is ground to a precise diameter to remove any deformities that may have occurred during the heat treating process.

			The inside of the flighting is then ground by hand to a smooth finish. This helps to make sure that wood shavings can travel along the spiral without getting stuck on a rough surface.

			Finally, the lips and spurs of the bit are sharpened on a grinding wheel.

			The auger is now ready to start boring.