Master the Miter
How to trim, glue up and reinforce this multipurpose joint
Synopsis: Gary Rogowski explains how to make miters that will serve you well in frames for veneered panels, applying wrap-around molding, or picture-frame construction. He offers tips on how to cut miters with a tablesaw or chopsaw, checking for square, fine-tuning your accuracy, adjusting during dry-fit stages, and how to glue up and clamp tricky pieces. He offers information on trimming by hand or with machines, how to strengthen miters and how to make splines and keys.
The attraction of a miter joint is easy to see. It is an elegant and straightforward method for joining parts that meet at an angle without showing any end grain. Whether you are building the frame for a veneered panel (tabletops, case goods), applying wrap-around molding or constructing a simple picture frame, a miter joint will serve your needs. But as the saying goes, the devil is in the details. The very visibility of the miter joint means that errors in machining or assembly are hard to conceal. However, with a little patience and lots of practice cutting and assembling miters, you too can master the joint.
Generally used for right-angle corners between two boards of equal thickness and width, miters are made with matching cuts. These cuts are at 45° so no end grain shows. But the miter joint isn’t reliable solely as a glue joint for most constructions. Where any real tenacity is required, strengthening with biscuits, splines or keys is always the prudent choice. In short, to get perfect miters requires perfectly mating joints, a slip-proof gluing system and at least one form of strengthening.
Cut miter joints with a chopsaw or tablesaw
No matter what type of saw you cut miters with, use a sharp, clean blade. Generally the more teeth to a blade, the smoother the cut, but…