woodworking newsletter milling slots vol. 7, issue 3 ... · milling slots woodworking newsletter...

Milling SlotsWoodworking Newsletter

Vol. 7, Issue 3 - January 2013

1/5 www.leevalley.com

With this simple setup it is possible to mill a slot safely in a small piece of wood. The one shown is 3/4” thick, 1-1/8” wide and 6-7/8” long. Squeeze the workpiece between two wide boards (here 3/4” MDF) that are between two pipe clamps or bar clamps on an anti-skid mat (router pad). Using a straight edge, ensure the workpiece is even with the top surface of the two boards. Mark the centerline, beginning and end of the slot to be milled.

Using a Handheld Router

Select a carbide spiral bit the width of the required slot to use in your plunge router. Situate the router over the workpiece so that the bit is exactly at the midpoint of the centerline. Use a straight board as a fence.

Clamp the fence to the wide-board support base, ensuring it’s parallel to the slot location. Using pipe clamps or bar clamps gives you enough room under the work surface for your C-clamps. If not, blocks of wood can be placed under each corner. Slide your router to each end of the slot and install stop blocks using more C-clamps. This step is optional, but I find it easier, safer and the final slot looks better.

Set the depth of the router bit to just beyond the thickness of the workpiece and make the cut in several shallow passes, plunging on the left side and routing towards the right side.

A slot milled in a small block of wood is shown, but, of course, the same method can be used to mill slots in wider stock.




Here is another great option when using handheld routers. The well known Workmate™, which has built-in jaws to hold your workpiece, makes a perfect base for routing slots.

At the Router Table I milled slots in two pieces of plastic-coated 3/4’’ thick MDF to make two adjustable split fences for a router table. Since the head of the T-bolts (sometimes called flange bolts) should be concealed, I milled stepped slots, which look similar to the ones on the back of this router table.

To establish the setup, raise the router so that the 1/4” bit protrudes over the top of the board. Set the router fence so that the slot is exactly at the center of the workpiece. Mark the leading edge of the cutter to determine where to start and stop the cut. Repeat on the other board. These marks guide you as to where to lower and raise the workpiece when milling both steps of the slots. When done, lower the router bit below the tabletop surface.

At 2” from each end of each of the two pieces, mark the limits of the slots and transfer those marks to the side closer to the fence. Clamp a stop block on the right side where the leading end of the cut meets the mark on the router fence, as shown.

Clamp a stop block on the other side where the mark is on the trailing end of the cut. You can mill these slots without stop blocks, but the process will be safer and more accurate with them.




This picture shows the setup with the workpieces ready to be milled.

Don’t try to mill the slots in one pass. With 3/4” thick stock (shown here), I mill the slots in three 1/4” passes, which is easier on the router and on small router bits.

Place the workpiece against the right stop at an angle, as shown. Turn on the router and, with a slow but steady motion, carefully lower the board until flat and slide it towards the left stop. Keep in mind that it must stay firmly against the router fence. At the end of the cut, back up a bit and slowly raise the workpiece, always keeping it against the router fence.

Repeat the process on both ends of both workpieces. When done, raise the router another 1/4” and make a second pass to deepen all slots. Don’t move the router fence or the stop blocks. All the slots are done without changing the setup; the same setup will be used for the second step of the slots.

As mentioned, the heads of the T-bolts are concealed within the surface of the split fence. Since the narrower side of the head is a little more than 1/2”, I chucked up a 5/8” twin-flute straight router bit. It should protrude from the router table top a bit more than the thickness of the head.




Using Templates, Guide Bushings and a Plunge Router

As before, rest the workpiece against the right stop block at an angle. Turn on the router and slowly lower the workpiece until flat, routing towards the left stop. Use stop blocks on both ends to guarantee identical slots every time.

Once you have finished creating the slots, chamfer all the edges to prevent dust accumulation.

First make a master template to use for creating more templates, as well as to mill longer slots such as dadoes and rabbets in casework. Select a 1/4” thick piece of hardboard, MDF, HDF or Baltic birch plywood. Rip the sides parallel. I recommend 30” long x 12” wide, which is long enough to mill dadoes on casework and wide enough to clamp it without interfering with the router path.

Insert a 1” bit in the plunge router and set the fence to center the slot. Mark the fence or use the split fences as I did to locate the router bit. (Note: If you are using a smaller bit, you can mill two narrow slots to achieve a 1” slot. Mill the first slot and then move the fence back to take the second pass.)

Mark both ends of your template 3” away from the edges to set the starting and trailing ends of the cut.




Text and photos by Serge Duclos

Serge Duclos started woodworking 40 years ago after purchasing a house. He soon found it was a way to relax from the stress related to his job as a human resources professional. Since retiring in 2004, Serge continues to enjoy his pastime and to update his bilingual woodworking blog http://atelierdubricoleur.wordpress.com with his projects, as well as his tips and techniques.

Using a 1” router bit, you can easily mill the slot in two passes. Set the depth of cut of the first pass to just over half the thickness of your template material.

When done, simply flip your workpiece, ensuring the same edge is against the fence, for the second pass. (Alternatively, you could raise the router bit to just beyond the thickness of the board and then finish cutting the slot.) Stop blocks cannot be used here because of the size of the panel.

After the template is complete, trim the corners at the miter saw and chamfer all edges. 1” guide bushings should ride freely with no side play.

Use the template, guide bushings and a plunge router to cut any slots needed for your projects.

woodworking newsletter milling slots vol. 7, issue 3 ... · milling slots woodworking newsletter...

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