Woodworker Serge Duclos explains how to build a router table sled that can be used for milling standard and angled cross dadoes, sliding dovetails, stub tenons and more.
This sled is designed to ride between two cleats along the two parallel sides of your router table top. If your table top is irregular, you will need to temporarily clamp two parallel cleats to your table-top edges or rip one side parallel to the opposite one.
Measure the width of your router table top and add 2” for the two 1” cleats that will be installed later. Using 3/8” or 1/2” plywood or MDF, cut a piece to that measurement for the bed of your sled.
Place the bed on your router table and loosely chuck up a 1/4” bit for alignment purposes. As shown, leave a 1” overhang from the closest table-top edge, measure to the center of the router bit and draw a centerline from the router bit parallel to this edge.
3” from each end of the centerline, draw 1” long perpendicular lines. Between these two lines, draw a line on each side 1/2” from the centerline. This will provide a rectangular pathway for the router bit.
To make the cut-out for the router bit path, make this simple template. Use two pieces of MDF or plywood about the same length as the bed and about 6” wide. From the same stock, cut two 1” wide spacers about 3” long.
Glue the four pieces together making sure the center slot is equivalent to the rectangular router path drawing. Let the glue dry about two hours.
Note that this is a great way to make any size of template to mill slots with the router.
After the glue has set, clamp the template on the bed over riser blocks, ensuring the router bit will protrude between those risers.
Finally, drill a 3/4” hole in the bed at one end of the template slot. Chuck up a 1/2” pattern bit or a flush trim bit to rout the router path slot in the bed following the template.
If you’re using a trimming bit that has the bearing at the top, the shown template and bed must be flipped over so the bearing will ride against the template.
If you’re using a pattern bit, which has a bearing at the bottom, the template must be on top, as shown.
Shown is the completed router bit path.
In the lower corner of the narrower side, mark 1/2” from the side and 1 1/2” from the end. This will become a pivot point later.
On the opposite side of the centerline, mark a mirror image of the previously marked pivot point, which will later be a second pivot point.
Drill the two pivot points using a 1/4” drill bit and connect them with a straight line across from one hole to the other. This line will be the start/stop point of the arced slots.
Use a piece of 1/4” plywood, MDF or hardboard about 5” by 24” (I used an HDF floorboard) to make a trammel. About 3” from one end, drill a 1” hole for a 1” guide bushing. From the center of this latter hole, drill a 1/4” hole at the opposite end according to the radius you get from the distance from the nearest pivot point to the centerline, times 2, minus 2”. A close look at the previous picture shows 8 1/2” x 2 = 17” and 17”– 2” = 15”, meaning I drilled the 1/4” hole at 15” from the center of the 1” hole.
Chuck a 1/4” plunging bit and install a 1” guide bushing on your plunge router.
Insert a 1/4” bolt into the right pivot hole and the trammel. Starting at 45°, draw an arc in the 1” hole of the trammel down to the line between the pivot holes.
Repeat the process on the other side to draw the opposite arc.
These arcs will be the stop/start point of the arced slots about 2” from the main center slot.
Raise your work so the router bit won’t damage your bench top. Clamp the bed, making sure the router bit won’t damage anything.
Sit the trammel on your work, insert the 1/4” pivot bolt and from the 1” hole, rout the first arc from one start/stop point to the other. I used C-clamps as stops.
Repeat the process on the other side.
Now chuck a V-groove bit in your router and flip the bed over.
Using the same process, make test cuts to find the appropriate depth for the chamfered arced slots so the head of the flat bolt clears the router table top.
Shown are the completed V-grooved arced slots.
Mill two 1” square cleats from hardwood about 2” longer than the bed and chamfer the two bottom edges.
Put the bed on your router table and clamp a cleat on either side making sure the router chuck is centered in the rectangular bit path and that there is no side play.
Secure the cleats to the bed with countersunk screws only, leaving the pivot holes free.
Drill the 1/4” pivot hole through the cleats. Since my router is centered on my table, each cleat gets a pivot hole. If yours is not centered, you may have a pivot hole in one cleat and the second somewhere on the other side of the bed between the cleat and the slot. This is where you will drill the pivot hole. You will also need to countersink from underneath for the head of the pivot bolt.
This is the best time to sand the sled to remove tick marks and pencil lines.
Using hardwood, mill a 3/4” thick fence 1 1/2” wide, the same length as your sled width, and clamp it to the sled, as shown.
Flip the sled over and drill through the fence in the pivot holes and the arced slots.
When working and flipping from one end to the other, you will have to move the two pivot and two holding bolts accordingly. All four will get a flat washer and a wing nut.
Finally, screw a 3/4” x 1” pad (I used MDF) to prevent router bits from chewing the fence. Your screws should be at the ends so they won’t be in the router bit path at any angle.
When setting the angle, you can use a protractor (as shown), a speed square or even a cut-off sample made at the miter saw. Also note that you must clamp a stop block, as shown, at the furthest end to prevent the sled from going too far into the pad. Set this stop block away by half the diameter of the bit you are using.
Here are sample cuts made with such a sled.
If you don’t have guide bushings, here is a simple guide you can make to mill arced slots. To make the guide shown, use one of the rods from your edge guide or buy any rod sized to fit your router.
You will need a piece of hardwood. Mine is 1 5/8” x 7/8” x 1 1/4” white oak. The exact size is not important. At one end, drill a hole halfway through for the rod. In the side, drill a hole for a set screw (I used a 5/32” Allen screw) and a through hole at the other end for the 1/4” pivot bolt. Drill the hole for the rod, and drill the two other holes 1/64” smaller than the bolts so they will make their own threads into the wood. Note the added locking nut.
Set the radius and mount your router on the workpiece. Insert the pivot bolt into the pivot hole and mill the arced slots.
Text and photos by Serge Duclos
Serge Duclos started woodworking 45 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 updating his bilingual woodworking blog atelierdubricoleur.wordpress.com with his projects, as well as his tips and techniques.