Note: Wood is not included.
While there are many ways to determine if an assembled carcase is square, the easiest method is to use “pinch rods” to compare the corner-to-corner measurements.
Unlike using measurements to compare the diagonals, pinch rods do not depend on reading and remembering dimensions. So they are much less prone to error. Also, pinch rods allow you to bring a carcase back to square using visual cues. Here’s how:
- Set the pinch rods to the shorter diagonal dimension of the carcase.
- Place the pinch rods into the longer diagonal.
- Apply clamp pressure across the long diagonal until half of the gap between the tool and the carcase disappears.
Pinch rods are also handy for transferring inside dimensions of a carcase – say, from a face frame to a door. And you can use them for transferring dimensions from full-size drawings to the actual piece.
Our pinch rods are based on a vintage example we saw at Roy Underhill’s many years ago. The bodies and thumbscrew are made in Kentucky from milled brass and include two No. 6 screws to attach the hardware to the wood of your choosing.
The wood should be straight, clear and dry. You’ll need two sticks that are 3/8” thick and 3/4” wide. You can make the sticks any length you like, but we prefer 32”. These lengths allow you to adjust the tool to handle assemblies from 32” up to about 58” – which can handle most full-size drawers and casework.
The custom-milled thumbscrew applies pressure in a concentrated point when you cinch it down. This makes a small indent in the wood, locking the setting, even if you drop the tool to the floor. (We experimented with versions with pressure plates. They didn’t dent the wood but they would easily lose their setting.) We built our first set of pinch rods about a decade ago and are still using the same set of sticks with absolutely no problems. But if the wood ever becomes too chewed up in about 100 years, you can easily replace it.
Like all Crucible tools, our pinch rods are made entirely in the United States.