When you’re building a cabinet or a bookshelf, the holes for the pins can just as easily be made with your hand drill and a basic wood bit. This is a shortcut that may or may not give you great results. What I mean by great results is that when your pins are placed into these bored holes, are they snug? If not, the strength of the shelf is compromised. Drilling with the common wood drill bit can result in the hole being cut a bit larger than the diameter of the bit being used, due to wandering. In order to minimize wandering, developers of bits created a Brad Point Boring Bit. The uniqueness of this bit is the sharp pin at the tip of the bit which bits into the wood to ensure a straight and even hole.
Brad point drill bits are specially designed to drill and bore clean holes in hard and soft woods without wandering. These drill bits have been designed with a center pin as seen in the images below and on the right.
A Brad Point Drill Provides a clean, straight, and accurately sized hole in wood. Not all boring is performed at a 90 degree angle and when one needs to bore at a slight angle the pin acts as the guide to the required position.
A clean cut is also not to be taken for granted. When one is boring holes for pins, with ordinary bits one may end up with edges which are jagged and have slight tear outs, leaving a rough surface. With the brad point bit, the outlining spurs of the bit shear the wood grain as it’s cutting and leaves a nice clean edge around the opening of the hole, eliminating the need for finish sanding.
Two Types of Brad Point Drill Bits:
Not all woods are treated the same when it comes to machining, and the brad point drill bit is no exception. There are two types of wood which require two different types of these bits: hard woods, and soft woods.
The difference between the two types of points is in the design of the outlining spurs. Because there is a certain amount of rubbing that occurs between the outlining spur and the wood before it is cut, the bit for softwoods is designed with rounded edges to hold down the end grains while shearing them off.
For Hardwoods, the outlining spurs on this bit comes to a sharp point and simply cut the stronger grains off clean. There is no rubbing and therefore minimal tear-out.
The following images are illustrations showing the structural difference between a brad point drill bit for hardwoods and for softwoods.