DIY Squaring Jig for Cabinet and Frame Glue-Ups
Gluing up a large cabinet case or face frame can be challenging, especially when you're working alone. Getting the assembly square adds another complication.
The usual approach is to measure diagonally from corner to corner with a tape measure. But on a large assembly, keeping the tape hooked securely while reaching the opposite corner can be frustrating.
This simple cabinet squaring jig solves the problem. It lets you compare the two diagonal measurements without juggling a tape measure or even reading a measurement.
Build a Simple Woodworking Squaring Jig
The jig consists of a notched corner block, a plywood backing plate, and a long hardwood measuring arm.
Start with a square piece of 3/4"-thick plywood for the corner block. Drill a centered hole, then use your table saw and miter gauge to make two 45° cuts that form a 90° notch.
Next, screw the corner block to a 1/2"-thick plywood backing block.
Make the measuring arm from a length of 1/2"-thick hardwood. Drill a hole near one end and attach the arm to the corner block assembly with a 1/4" hex bolt.
The notched block registers against a corner of the assembly, while the long arm reaches diagonally toward the opposite corner.
How to Square a Cabinet or Face Frame
Using the jig is straightforward.
Position the notched block over one corner of the cabinet or frame and secure it in place. Extend the measuring arm diagonally across the assembly to the opposite corner.
Place a piece of masking tape near the end of the arm and mark where the opposite corner falls.
Now move the jig to check the other diagonal.
Compare the second corner position with the mark on the tape. If the two diagonals match, the rectangular assembly is square, provided the opposite sides are equal and straight.
If they don't match, adjust the assembly or clamping pressure and check again.
There's no need to remember measurements or wrestle with a tape measure.
This handy shop-made jig makes it much easier to square large cabinet cases and face frames during glue-up — even when you're working alone.
The Secrets of a Face Frame
A square, well-assembled face frame is the foundation of a great-looking cabinet. From laying out the parts to choosing joinery and keeping everything aligned, a few practical techniques can make the process easier.
Learn how to build accurate, attractive face frames that fit your cabinets and help make assembly go smoothly.
LEARN FACE FRAME BUILDING TIPS → Build Better Cabinet Face Frames
