How to Make a Mortise With a Drill Press
- 1). Measure the location of the mortise on your workpiece. Mark the outside lines of the mortise with a knife or marking gauge. Cutting the wood like this helps prevent the drill bit and chisel from going past your layout lines. Once you have marked the location of the mortise, go over the cut lines with a sharp pencil to make the lines more visible. The pencil will follow the cut lines so you won't have to worry about marking an incorrect line.
- 2). Measure and mark the middle of the mortise and score a line down the middle from end to end. Now mark this line with the sharp pencil as well. This line will be used to guide the drill bit to exact center, as you will see in the next step.
- 3). Select a forstner bit or brad point bit that has a diameter the same width of the mortise or just a fraction of an inch under. Take the bit and put the point on the center line close to the end of the mortise, making sure that the bit will not drill past the end mark. Tap the bit with a small hammer to make an indentation on the center line. Do this for both side of the mortise. This ensures the drill bit finds exact center by starting on that hole.
- 4). Mount the bit in the drill press and set the depth stop to the exact depth of the mortise. Hold the workpiece firmly on the drill press table, or clamp it in place. Lower the bit to make sure its point is hitting the hole you punched earlier. Now turn the drill press on and once the bit reaches full speed lower it in to the wood, raising it often to eject wood chips.
- 5). Drill each end of the mortise first. Then work towards the middle of the mortise, drilling on one end and then the other. This sequence makes sure the drill bit has enough surface to contact and drill straight down instead of wandering. Keep drilling like this until you have cleared the majority of the wood in the mortise.
- 6). Stop the drill press and remove the workpiece. Select a wide chisel that close to the length of the mortise. If the mortise is longer than your chisels, than select the widest one you have. Pare away the waste on the sides of the mortise in thin slices until you reach the cut line of the mortise. Make sure you keep the chisel straight up and down as you pare. Do this on both sides of the mortise.
- 7). Select a narrow chisel which matches the width of the mortise. Again, pare away the waste in this slices until you reach the cut line. Keep the chisel parallel and straight as you pare away the ends. Clear the shavings out of the mortise as you go, and make sure you pare to the bottom of the mortise.
