Which drill bits should you use to drill dowel holes?
Using a normal drill bit (also called a twist bit) to drill holes in wood can cause splinters to break off the wood along the grain and make a mess of your wood’s surface.
If you’re really unlucky, it can cause your wood to crack. This is all to do with the pressure that the point of the drill applies to the wood surface.
Twist drill bits have tips that are quite wide and blunt. Something with a sharper point is required to avoid causing damage.
It’s easiest to think of this along the same lines as trying to cut a cake with a baseball bat. It could work, but the results would be very messy!
Wood Cutting Drills
Wood cutting drills have this exact principle in mind. The first part of the drill to enter the wood is a sharp point that penetrates the wood’s surface without the use of excessive force.
The next part of the drill to make contact with the wood is a cutting edge that spins in a circle and cuts the hole to the size you need.
There are a few different types of drill that are all suitable for use with dowelling projects. These are briefly described below.
Brad Point Bit
Brad point bits are also known as lip and spur bits or dowelling bits.
As their alternative name suggests, these are the most common types of drill bit used for dowelling because the sharp point at the end of the drill does not stick out much further than the cutting edge of the drill bit.
Spade bits are flat and have a triangular shaped point that makes a small hole before the edges of the ‘spade’ (the wider part of the drill) come into contact with the wood surface.
An auger bit also has a thin, sharp point at its tip, and the rest of the drill is shaped like a corkscrew. This makes it easy for wood to be removed during the drilling process.
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Due to their corkscrew shape, auger bits have a reputation for being aggressive and almost ‘biting’ wood. Therefore, they may be less suitable for precision work. The long spike on spade bits makes them difficult to use accurately.
While the others can be used at a push, brad point drill bits are the best tool for dowelling as they drill clean, smooth holes.