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D4031 Mortising Kit Instructions
Making a Mortise
Proper alignment of the workpiece and chisel is essential
to making good mortise and tenon joints. The instructions
below describe one method of creating square joints with
an evenly-spaced mortise. Place a scrap board on top of
the drill press table if a through-mortise is to be made.
To make a mortise, do these steps:
1. Install the chisel into the cone, rotate it so the
opening is positioned toward the operator and is
square to the fence, as shown in Figure 5, then
secure with the knob.
2. Secure the drill bit into the drill chuck. Slide the
drill bit into the chisel as far as it will go and then
allow it to drop back down 1⁄32" - 1⁄16", as shown in
Figure 6. If this is not done, wood chips generated
by the cutting action will have no place to go,
resulting in excessive heat and damage to the tool.
3. Measure the surface of the workpiece that is to have
the mortise. Subtract the size of the mortise chisel
and divide this number in half.
Workpiece = 0.75"
Chisel = -0.375"
0.375" ÷ 2 = 0.1875"
4. Mark the workpiece where you want the mortise and
clamp it to the fence.
5. Loosen the adjustable handles on the fence. Lower
the chisel with the downfeed handles on the drill
press and make adjustments to the fence until the
marks on the workpiece are aligned with the chisel
as in Figure 7. Tighten the adjustable handles. If the
fence cannot be adjusted close enough, adjust the
table on the drill press until the chisel and marks are
aligned.
6. Set the speed of the drill press between 900 and
1200 RPM.
7. Carefully inspect the alignment. When you are
satisfied that the setup is worthy of being tested,
replace the workpiece with a scrap piece of lumber
that is the same size as the workpiece. Attach the
hold-down bracket and rod(s) and make a cut.
Figure 7. Aligning the chisel and marks.
Figure 5. Example of squaring a chisel.
Figure 6. Proper drill bit depth.