How to drill a hole for a dowel with a brad point bit
|Dowelling is a sturdy and dependable way of making wooden joints for furniture, shelving and general woodworking. However, it requires a good deal of accuracy, especially when drilling holes for the dowel pegs.
|Brad point bits fit the bill perfectly, as they drill such clean holes and are produced in sizes that accommodate the most common sizes of dowel. These are 6mm, 8mm and 10mm (dowel pegs are most commonly sold using metric measurements). The closest imperial equivalents are 1/4″, 5/16″ and 3/8″ respectively.
Step 1 – Choose the right size of drill bit
If you are using fluted dowel pegs (pegs with small channels cut into the sides), you should choose a bit that is the same size as the peg.
|If you’re making a dowel joint where the dowel will be fully concealed, and your dowel pegs are not fluted, you should choose a bit that is 1mm larger than your dowel peg.
|This is because you need to allow room for glue to spread inside the dowel hole when you complete the joint. If you don’t, and the excess glue has nowhere to go, the resulting pressure can cause the wood to crack.
This is only a problem if both ends of your dowel will be concealed – if your dowels are going to be visible on one end then any excess glue will be pushed out of the hole when the peg is inserted.
Step 2 – Plan for accuracy
Accuracy is paramount when making dowel joints. Your dowels must align perfectly or the joint will not form properly, leaving gaps or creating odd angles.
|Drill holes must be perpendicular to the surface or edge of the workpiece in most cases. The best way to guarantee that your hole will be perpendicular is to use a drill press.
|If you don’t have a drill press or would rather work by hand, using a dowelling can help you to stay accurate. These provide you with a template that can be secured to your workpiece, and usually contain bushings (guide tubes) that help you to drill a perfectly perpendicular hole.
For more information, see:
|You’ll also need to make sure that your holes are drilled to the right depth. For this, you will either need to use a depth stop, which can be secured to your bit using a hex key, or the integrated stop on your drill press (if it has one).
|Normally, you would aim to have half of the dowel peg inserted into each piece in the wooden joint, with 1mm either side to allow space for glue.
For more information on this process, see:
|Before starting to drill, fix your depth stop onto your bit securely, or adjust the stop on your drill press to the depth you need to drill.
For more information on depth stops, see: What drill bit accessories are available?
Step 3 – Drill hole
Checking your drill speed and making sure the bit is correctly aligned, drill your dowel holes.
|You should be left with clean, neat holes that are the ideal fit for your dowel pegs.