In the first stage of the bit-making process, steel rods are forged to match the desired diameter of the finished bit.
These rods are hardened, by heating them until they are red hot, then rapidly quenching them in water.
They are then tempered, where they are heated again until they appear light brown, then left to cool at room temperature. This is an important part of the manufacturing process that makes them hard enough to drill through very hard wood species (such as lignum vitae) and plastics.
The flutes of brad point bits are ground into them in much the same way as twist bits. Computer-controlled machinery twists the bits against a grinding wheel, which cuts the spiral flutes with greater precision than would be possible if the bits were handmade.
For more information, see: How are twist bits manufactured?
The flutes on brad point bits are cut at a shallower angle than those found on a twist bit, which allows waste to be evacuated from boreholes more quickly.
When it is time to shape the tip, the bit is ground by computer so that its brad point is perfectly centred. This process ensures that the tool is accurate.
As part of this process, two sharp spurs are ground at an angle to the tip of the bit so that they can cut around the circumference of a borehole for a neat finish.
For more information on this process, see: {{widget type=”cms/widget_page_link” title=”How to make a brad point bit from a twist bit” template=”cms/widget/link/link_inline.phtml” page_id=”3628″}}.