Which drill bits should you use to drill dowel holes?

 
     
     
 Shop for Dowels 
     
     
 Image of a twist drill bit which is the standard type of drill bit used with most drills 

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.

 
     
 A piece of wood that has cracked from having a hole drilled into it 

If you're really unlucky, it can cause your wood to crack.

 
     
 Tip of a twist drill to show how wide and flat the point of the drill is compared to a dowelling drill bit 

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.

 
     
 Image to illustrate that drilling into wood with a twist drill can be like trying to cut a cake with a baseball bat 

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

 
 Image of the tip of a woodcutting drill bit which is sharp to prevent splintering or cracking 

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.

 
     
 Diagram showing where the cutting edge is located on a dowelling drill bit 

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.

 
     
 Image showing the types of drill bit that are suitable for dowelling 

There are a few different types of drill that are all suitable for use with dowelling projects. These are briefly described below.

 
     
 A brad point drill bit which is the most suitable drill for use with dowelling 

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.

 
     
 A spade drill bit which is suitable for dowelling but not with a hand drill 

Spade 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.

 
     
   Wonkee Donkee explains that the spur on a spade bit is long and that it should be taken into account when drilling dowel holes 
     
 An auger drill bit which is suitable for dowelling 

Auger bit

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.

 
     
 Wonkee Donkee recommends brad point drill bits 

Wonkee Donkee recommends...

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.

 
     
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