Mortising & Drilling Fences for your Drill Press

Our drill press does dual duty as a mortising machine and a woodworking drill press. Only once in a while does it drill steel. In our business it seems that we are always cutting mortises. The original mortising attachments that came with our Jet drill press had small clamps and a fence that was less than satisfactory. A couple of years ago we designed a system that works great for mortises and also standard drilling

Using 2 pieces of ¾” oak plywood cut to 17” deep and 20” wide. Take the bottom piece and locate it in the center of your drill press table. Locate 2 5/16” holes for mounting to the table. Be sure to check the underside of the steel table as most have webbing reinforcement and you need to locate the holes out of this area. Drill both the steel and the plywood and use a ½” Forstner bit to countersink the bolt heads in the plywood. Mount the board to the table with washer and nuts and epoxy the bolt heads in place. Let this dry overnight and glue the second piece of plywood in place.

Rip enough material 3/8” x 1 ½” cap strips to hide the edges of the plywood and install with glue and brads. Locate the groove for the T-Track 4 ½” from the outside edge and route with a ¾” router bit or use a dadoe blade on your table saw. Install the T-Track with screws.

Re-install the table on the drill press and install a drill bit and find the center. This will allow you to locate the center of the disposable wear plate. More drill press tables are ruined after a couple of years by holes of all different sizes. This disposable plate will keep the table looking great for years. From the center measure a 4” square. At each corner of the square using a ½” Forstner bit drill a hole ½” deep. This creates a finger hole to remove the plate. Set up your plunge router with straight cut bit set to cut ½” deep and clamp a wooden straight edge to route the relief for the plate. Make at least three 4” square plates ½” thick to keep as spares.

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Measure in from the sides 2” and 1” from the rear for the 3/8” slots for the bolts for the fence. They are 10” long, which is well past center. The material is 1 ½” thick and will need many small cuts with a plunge router and fence to cut through the table.

Fences

Standard drilling fence is 2 ¾” high by 21” by ¾” thick with a rear support 2” wide and 20” long. Install the fence to the rear support with 5 1 ½” drywall screws that are counter sunk. Double check to assure that the fence is square. We have used 5/16” star knobs and you need to locate them on the rear support so that they clear the upright back of the fence. Drill these two holes at 3/8”.

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Mortising fence is made from 6 ½” by 21” x ¾” material. Locate the center and layout a 3” wide by 3” deep section for the mortising attachment to clear the fence. Cut this with a bandsaw and sand smooth. Mark the T-Track groove ¾” from the edge of the relief and cut with a router or a dadoe blade on the table saw. We rounded both sides with a French curve just for looks. Cut the rear support 2 ½” wide and install to the fence with 5 counter sunk drywall screws. Behind each T-Track install a rear support 2 ½” by 5 ½” to support the mounting screws for the T-track. Double check to assure that the fence is square to the table.

Locate and drill the rear mounting holes for the knobs the same as the drilling fence. In the center of two 2” by 2 ½” blocks drill the mounting holes for the hold-downs and install with two 5/16” T-knobs.

We have found that a tapered finger jig is very good for holding the material against the fence and it is easy to adjust the tension based on your direction of work.

Finish all sections with 2 / 3 coats of Polyurethane and you have the perfect mortising and drilling jig.

Next month we will discuss mortising chisels, sharpening and machining to fit larger sizes o your drill press as 1/2" is many times the largest available

Brian Murphy
American Furniture Design Co