Compound mitre saws (a.k.a. chop saws) need adjusting—when they’re new and periodically after that—so the cuts match the angle you set. By checking and adjusting so the tool cuts square in vertical and horizontal orientations, you’ll know that other mitre and bevel angle settings will be spot-on. And you don’t need special tools for this fine-tuning.
Start by cutting two test pieces from the end of a board that’s as wide as you can slice in one cut (ideally 10″–12″ wide). Lay the board flat, with the tool set to 90° in both bevel and mitre positions. Make the first cut to trim an end fresh, then a second and third cut to remove two pieces, each about 8″.
With both pieces still on your saw and tight to the fence, flip one edge-for-edge relative to the position it was cut in, then push the ends together. Do the cuts meet without a gap? If so, then your saw is cutting as it should in the mitre orientation. If not, then you’ll need to loosen the adjustment screws, tweak in the correct direction, then trim ends again and check for a gap. Many mitre saws allow the entire mitre angle scale to be moved one way or the other to get mitre angles correct, but check your owner’s manual for details.
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Repeat the process to test the 90º bevel setting.
1) Place a 1×4 or 1×5 board on edge against the fence, 2) make a cut, then 3) do the flip test. If there’s any gap, tweak the 90º bevel stop at the back of the saw, then test again.
The 90º and 45º bevel stops are independent, so it’s best to finesse both. To test the 45º bevel setting, make a single 45º cut across a piece of 1×3 (laid flat on the saw), then place the two pieces on edge, end to end, forming a 90º corner. Check the 45º cut with a carpenter’s square. If the joint is not gap-free as the wood sits against the two legs of the square, tweak the 45º bevel stop and test again.
This article was originally published in the August 2024 issue of Cottage Life.
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