I'm working on an 8ft x 12ft climbing wall. I have 3/4 inch ACX plywood attached to a frame. Since the frame isn't perfectly square, the plywood overlaps on the edges (up to about 1cm) so I need to shave it down. What's the best tool for the job?

I was thinking of using a block plane, but I've heard it can tear the edges of the plywood. Would a belt sander be better?

  • 3
    Why is the frame not square? Can you fix that instead of changing the shape of the plywood?
    – Hank
    Commented Feb 20, 2013 at 3:47
  • Yes, making the frame square would be ideal, but I'm not sure if I have the skill to get it closer (and it would be a huge project to disassemble it now). I'm sure a good builder could teach me some tips for getting it straighter.
    – balexand
    Commented Feb 21, 2013 at 20:53

2 Answers 2


A block plane might work but you're going to have a very tough time taking down 1cm of wood over such a long length. If you do use a plane, go in small increments and make sure you keep your blade as sharp as possible.

A belt sander will work better, provided you use 40 or 60 grit sandpaper. Anything higher (smoother) and it will take you an eternity. My biggest caution with a belt sander is to be careful to work evenly. It's easy to get distracted and create a divot where you've sanded too much.

If the sanding is daunting or you want something with more precision, I would recommend using a handheld router with a flush trim router bit. This will get you a nice clean edge. I would try to get the board trimmed down to less than 1/4" overhang or so first if possible, with a jigsaw or something. Then clamp a long straight piece of wood along the line you want to keep.

If there's enough of an overhang to get enough stability for a circular saw and a guide, that would also work. But it sounds like the overhang is too small for that.

  • 1
    Since it is a climbing wall and not a piece of furniture, I'd use a belt sander to bring the plywood flush to the frame. Commented Feb 20, 2013 at 10:32
  • 1
    Heh, yes a belt sander is probably the best combination of safe, cheap, and effective, especially if it doesn't need to look perfect. But I do love a good router...
    – Hank
    Commented Feb 20, 2013 at 18:48
  • Thanks! I've ordered a belt sander. It's good to learn about a flush trim router bit, but I'm not likely to use a router often so I'd rather not spend the money.
    – balexand
    Commented Feb 21, 2013 at 20:50
  • I needed to remove a bit from the edge of plywood shelves, maybe 1/8". A finishing sander with 100 grit took approximately forever, but a plane did the job quickly. Just a datapoint. Commented Sep 9, 2022 at 21:38

Suppose the black square is the area to be planed from the plywood, then cut near the 4 edges of near the square with 45 degree angle (2 bottom edges is done for reference in the attached figure) with a hacksaw blade or whatever and finish with a hand file (not really necessary). Later plane across the square as usual. The edges will look almost good, however while nearing the square, if you shift to a small smoothing plane instead of a jack plane, the result will be 100% perfect.

Sorry for my bad photoshop work.

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