Most of us learn to joint an edge with the board clamped vertically in the vice, and the plane upright as you would expect (See: A Beginner's Guide to Edge Jointing). It’s a generally reliable method, but it’s not the only way…
There’s a lesser-known technique that deserves more attention, particularly for thin boards: using a jointer plane on its side to joint an edge. Done correctly, it’s accurate, controlled, and surprisingly forgiving.
Why Plane on the Side?
At first glance, the idea sounds awkward. Why turn a perfectly good jointer plane on its side when it’s designed to sit flat?
The answer lies in reference surfaces.
When jointing an edge conventionally, you’re relying on your eye and hand pressure to keep the plane square to the face. Any small tilt — especially over a long stroke — shows up as an edge that’s slightly out of square.
By laying the plane on its side, you can reference the side of the plane body directly against the workbench. The plane becomes its own squaring jig.
Setting Up the Work
The setup is simple but important.
First you need a flat and smooth reference surface. This could simply be your workbench, but if yours has seen better days then appropriately sized offcut of plywood or MDF will work.
Next, secure the board flat on the bench with the edge you want to joint facing outwards. Bench dogs and holdfasts are ideal here, but clamps can work too. The key is that the edge you are jointing is clear, and the board is raised slightly off the benchtop to allow the plane to cut the full width of the edge.
The plane is then laid on its side, with one cheek running on the workbench. As with any jointing a longer jointing plane works best, but a jack or smoothing plane will work for shorter boards.
The Planing Action
With the plane on its side, grip it firmly but without forcing it keeping the plane’s sole gently pressed against the face of the board. The bench supports most of the plane’s weight, which is one of the hidden advantages of this method.
Proceed as you would when jointing conventionally – taking out the belly of the edge if required before progressing to full-length strokes.
Checking for Square
Once you have taken a few strokes, check the edge is square to the face of the board – any errors can be corrected by making small adjustments to the angle of the blade.
As with more conventional jointing, two boards can be clamped together so that their edges are planed at the same time – resulting in complementary angles and a flat glue up even if the edge is not quite square.