Scalable Router Sled and Thicknessing Jig




Introduction: Scalable Router Sled and Thicknessing Jig

About: CAD Designer and CNC programmer by day. Woodworking enthusiast, woodworking teacher and DIYer based in Ontario Canada.

A common way to surface large rough boards is with a router sled. This allows the router to pass across the board and remove an equal amount of material. A thickness planer will also do this but the maximum width of board that can be passed through a typical planner is 12 to 13 inches. The larger industrial planners are much more expensive and require much more space. Also short pieces cannot be planned easily because they get stuck between the feed rollers in the planer. I wanted to plane small pieces that cannot fit in my planer. Some of the cutoffs are between 4 and 10 inches long by 3 to 6 inches wide. I've tried using double sided tape to hold the pieces down to a longer board but sometimes they would come loose and get chewed up in the machine. I tried using carpet tape but I couldn't get the pieces off easily without breaking them.

This jig can be scaled for large table tops (if more vacuum hold-downs are used and a larger router is used) or used for planning small pieces that are too short for the planer. The jig utilizes a vacuum hold-down with a built-in venturi to create suction from compressed air.

If you are new to using a router or have never used one before I suggest enrolling in the woodworking class where you will learn basic woodworking practices as well as using a hand router.


Router Trimmer

Vacuum Pod

Air Compressor

Surfacing Router Bit

3/4" plywood for the base and sides.

1/2" Plywood for the router base plate and stops

#8 x 1 1/2" wood screws

#8 x 5/8" wood screws

1/4" NPT Quick connect airline fitting

1/4" NPT Ball valve

Step 1: Choose Your Router Trimmer and Bit

I'm using a 1 Horse power Bosch Colt and a 1" Diameter surfacing bit. The height of your jig depends on the length of your router bit and the thickness of boards you would like to plane. I'm trying to bring the pieces of wood down to an 1/8". This will require me to make a very shallow jig. If you are hoping to surface thicker pieces a taller jig will likely be better.

Step 2: Remove the Base Plate of the Router

Use this as a template to locate your holes and draw where the bolts are going to go.

Step 3: Locate the Centre of the Baseplate

I cut a piece of 1/2" scrap particleboard the same width of the base plate by 3 times the width of the vacuum pod. 4" x 16". I then layed out the center of the wood with 2 diagonal lines from corner to corner of the piece of wood. Then I set the base plate in the center of the wood and traced it out.

Step 4: Drill Holes for Mounting the Router

Drill a large hole in the centre of where the router base plate is going to go. Make sure the router bit will pass through the hole without any obstruction. I used a 1 3/4" Hole saw which was plenty big. Next drill the holes where the bolts are going to go. I used a 1/2" forstner bit for the bolt head and a 3/16" drill bit for the shank of the bolt to pass through.

Step 5: Bolt the Router to the New Plywood Base Plate

The original bolts were too short to attach the plywood so I found longer bolts with the same thread. These bolts should be recessed to prevent scraping on the jig.

Step 6: Cut the Plywood for the Box

I cut the box to be slightly wider than the vacuum pod and slightly longer. If you are planning on using this for pieces that are much larger than the vacuum pod I would suggest adding blocks the same height of the pod to help support the piece. I added a hole for the shop vacuum to attach to the jig. This is an extra but I would it very helpful to remove the debris. As well I drilled a 5/16" hole where the airline runs into the jig. This keeps it from getting pinched or cut by the router.

Step 7: Assemble the Box

First I attached the ends of the box. I used #8x 1 1/2" wood screws. I didn't use any glue on these joints in the event that I need to change the height of the jig. Once the ends were on I screwed on the sides. Try to keep these as even as possible so that the jig planes evenly.

Step 8: Assemble the Vacuum Pod

I screwed down the vacuum pod with #8 x 5/8" screws. Next I pressed in the medium sized gasket. The pod comes with 3 different sized gaskets to use depending on the size of the part you are trying to hold. Its best to use the largest gasket possible for the best hold. Keep in mind if there is any gap between the gasket and the edge of the wood the vacuum will not be able to seal properly. Once the air is flowing and the vacuum is created the piece should not be able to move.

Step 9: Hook Up the Airline

The pod comes with a small push-fit airline and a 1/4" NPT (National pipe thread) fitting on the end.

The hose presses into the push-fit on both fittings.

To make it easy to supply air on and off I used a 1/4" NPT ball valve to control the air and a 1/4" male quick connect fitting on the end. That way I could turn the air on and off easily between parts without disconnecting the airline.

Step 10: Add the Stop Blocks

I screwed on 2 small blocks at the ends of the plywood router base plate. These can be adjusted to keep the router bit from cutting into the sides of the jig.

Step 11: Test Out the Jig

Test the depth of cut by placing a piece of wood onto the vacuum pod and turning on the air.

Press the wood down.

With the router off place the router base onto the jig with the router bit onto of the wood.

Depending on the gap between the base plate and the jig that will show your depth of cut. If the depth of cut is too deep the router bit could break. Take slow shallow passes. Try to keep the router away from the piece until the router is at full speed. Then begin slowly moving into the piece.

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    3 years ago on Step 11

    What a fantastic idea. Very practical for utilizing all those little valuable scraps of wood that now have a new purpose. Keep up the good work.


    Reply 3 years ago



    3 years ago

    Looks good! : )


    Reply 3 years ago

    Nice job! I own a milling machine and do this job there. But when I clamp the piece down she rarely stays flat after, maybe next time I will try your way with my router.


    Reply 3 years ago

    Thanks! This is my first Instructable. I'm planning on making some more.