169 – Flatten Boards Wider Than Your Jointer

Video - April 11, 2012

There is nothing worse then when you have an absolutely beautiful board that is nice and wide and you realize it won’t fit on your jointer. So you have no choice but to rip it in half, joint each piece separately, and then glue the pieces back together. Wouldn’t it be so much nicer if we could just keep everything whole and preserve the wood’s natural beauty without a grain-interrupting glue line? Well, it’s your lucky day because I’m going to show you two techniques that will help you keep your wide boards intact. Both methods utilize the planer for final flattening, but one method starts with a hand plane and the other starts with the jointer.

The Hand Plane Trick

It should be said that the traditional way to handle a wide board would be to simply mill it 4-square with your hand planes. But this method is intended as a quicker, more beginner-friendly, hybrid alternative. It begins with planing one side of the board flat. By laying the board face down on a known flat surface (workbench, assembly table, tablesaw…), you can simply rock the piece back and forth to determine if any twist, cup, or bow exists. Mark the high spots with a pencil and begin planing them down. Keep testing your progress by flipping the piece over and checking for rocking. Eventually, you should end up with a reasonably flat and stable board. Once you are confident the one side is flat, you can simply send the board through the planer with the flat side down and then mill the edges using your preferred method.

Here’s a quick tip. The initial flat surface doesn’t need to be perfectly flat. If the board is slightly concave and it isn’t too long, it can still register perfectly during a pass through the planer. So for the sake of expedience, don’t shoot for dead flat. Shoot for even registration around the perimeter and if the center area is hollowed out ever so slightly, that’s ok.

The Jointer Trick

So your jointer is only 6″ side and your fancy board is 9″ wide. No problem. But before I go into detail here, note that this technique does require the removal of the jointer’s safety guard. Exercise the highest level of caution during this process and place the guard back on the jointer immediately after! Don’t make me come over there!

Planer Trick RidgeOnce the guard is removed, you should have the ability to run an extra wide boards over the tables. Take one or two passes and flip the board over to see what you’re up against. If the board is badly twisted, it may take a few more passes. What you’re looking for is a little ridge. Only 6″ worth of the board’s width is making contact with the blades. So the overhanging area should appear as a raised portion of stock running the length of the board.

Now here’s the “trick”, and you have two options. First, you can simply double-stick tape a piece of flat sheetgood stock to the flat milled portion of your board. Planer Trick SledThe sheetgood sled can be anything from plywood to MDF to particle board and should be at least the width of the flattened section and the length of the board. Once securely attached, you can flip the sandwich over and run it through the planer. The uneven raised portion of the board will now be raised above the planer table surface and won’t have any impact. The flat section of the board is now registering against the sled and since the sled is flat as well, we are able to achieve perfect flat registration as we pass the assembly through the planer. One the new face of the board is clean and flat, we can disassemble the sandwich and run the board through the planer one last time to remove the raised uneven portion.

The second option after the initial flattening is to remove the uneven raised portion using a hand plane. A few passes with a hand plane is all it takes to flush up the rest of the surface. Once flat, you can simple pass the piece through the planer with the clean and flat face down.

Wanna build the Split-Top Roubo?
Get immediate access to all of the videos in this series!
Sign up for the Wood Whisperer Guild today!



The best printer of 2021