Many woodworkers struggle with leveling the front edges of a frameless cabinet. You have grain running at right angles all over the place. How do you get all the front edges flush without spelching the corners and also produce a shimmering, ready-to finish surface?
The trick is to use a little sandpaper to break the edges that can spelch, then plane the joint at an angle that fools the wood into producing a nice finished surface.
To break the edges, I take a piece of worn-out sandpaper and lightly chamfer the corners that could spelch if planed cross-grain. Don’t over-do it. Just a couple swipes will strengthen the corners enough for a couple strokes of planing.
Then level the joint, getting the surfaces almost flush. Here I’m planing a shelf flush to a cabinet sides. When I’m a stroke or two away from flushing the two surfaces, I set the tool for a light cut and skew the plane at 45°. Then I level the joint.
The 45° skew fools the grain of both pieces into producing a clean surface on both the shelf and the side.
After every three or four strokes with the plane, feel the corners to see if the corners you sanded away have become sharp again from planing. Break the edges gently again with paper and continue to work the joint until it looks flush and ready to finish.
Small chamfers made with sandpaper – invisible to the naked eye – can save your butt from spelching in many cases. This is just one example.
— Christopher Schwarz