Make a Router Planing Jig

No Planer/Thicknesser, or maybe it's not wide enough? If you have a router, then this router planing jig might be right up your street.

I built mine as an improvement over what I've used in the past to plane wide planks for waterfall tables. I estimate it halves the time to get the same job done as before - not bad for something cheap, easy, and quick to build!

Let me show you how I built and use it.

Use the Instructable and video to make your own - there is even a SketchUp model for free download!

The Options

Flattening and thicknessing a board, if you don't have a jointer/thicknesser (or one big enough), can be good exercise and fun with hand planes.

Less physical effort using a plain router sled, or a power hand plane.

But for speed and accuracy, a router sled on which you can lock two axes is the way to go.

Build the Bed & Rails

All dimensions will depend on what size work you intend doing, so I give mine purely as an example

You need to prepare two identical, straight, parallel rails for the sled to ride on. I used 2"x4" lumber, and prepared both pieces, with hand planes

The base will be attached in grooves, which now get routed in each of the rails. I set the grooves so that there would be almost 2¾" below the sled - enough for the worst warped planks I'm likely to buy in the future!

The base is any flat, stable, sheet material. Cut wide enough to fit the rails and still have the planing width required

Attach the rails to the base with screws set at opposing angles. This 'dovetailing' will give more strength against the rails being pulled off

A Sliding Sled

I used an off-cut of ¾" (18mm) construction ply for my sled. Something stiff and stable is what's required.

One side gets a two-wheeled bogey attached. The other side a single wheel.

The bogey chassis' are made from the same lumber as the rails, but ripped down by ¼" (6mm) so that it doesn't catch the ground.

Axle holes are first bored through, and then the spaces for the wheels made. For the single wheel bogey, which will be used to make a snug fit to the rails, the corners are removed as shown to expose most of the wheel

Wheels and axles are fitted, and the sled set upon the rails. Now the two wheel bogey is clamped and then screwed to one side of the sled. The single wheel bogey is attached with a pivot screw, and adjusted to pull all wheels into contact with the outside of the rails, before a fixing screw is added

Attaching a Router

I chose to attach my router with a long rod through the parallel fence attachment holes on the router base. A single rod is all that is required

Fixing blocks for the rod were made in hardwood (beech). These are then attached to the sled, using screws so that it is easy to remove. The rod, together with the thumb screws on the router, give the router it's travel across the bed, and the ability to lock it in this axis for lengthwise routing

Stops are installed, which the router base will contact when the router cutter reaches the rails, preventing damage (you can see the limit lines I transferred from the rails to the deck to set these stops). Additional stops could be fitted to the sled deck, as required, to limit cutter travel within the work

Finishing Steps

With the cutter installed (I'm using a ½", twin flute), a cutter access slot is milled through the deck

A hole for a dust extraction hose is bored through the deck. This seems to collect most of the finer dust, with the larger chips just being left around the work. So, no clouds of dust to breathe in!

I also added a scale to the deck, with divisions fractionally smaller than the cutter diameter. This makes stepping the router over after each pass a lot quicker and accurate. For a slightly better finish, step over half a division for each pass

Using the Jig

Work Piece Fixing

The work should be held securely to the base

Wedges are used to support 'high' areas - stopping the work from rocking

Where there is sufficient waste material, either at the edges or ends, then through screwing can be used (counter bore clearance holes, so that screw heads lie below the final cutter depth to be used. This will prevent running into a screw by accident)

The work piece in the photo didn't have waste areas, so I used a fixing block each end, which was screwed into the end grain in non-show surface areas

'Planing'

The highest overall point on the work is found, and the router depth set to remove perhaps 2mm

Roughing

The sled is then moved in a series of straight passes (advantage of locking the router base on it's rail), with each pass slightly overlapping. At the end of each straight pass, the router base is unlocked and slid across the deck by one division of the scale, before re-locking and returning to cut in the opposite direction. Once a full width has been completed, if required, the router depth is increased and the process repeated. This continues until the entire surface has been flattened

Finishing

Same principle as for 'Roughing', except that:

Stepping over distance each pass should be reduced to less than half cutter diameter

Cutting should only be done in one direction (the one giving the best finish), returning the sled each pass before stepping the cutter across for the next pass

Cutting depth should be reduced to ½mm or so

Clear chips after each pass