by Megan Fitzpatrick
A diemakers’ square with a narrow blade is an excellent tool for determining minute problems with your joinery, allowing you to get in between narrow dovetail pins, for example, to check for sloping walls. But a true diemakers’ square (on which the blade angle can be adjusted for patternmaking) is quite expensive, even on the secondary market (though Lie-Nielsen sells a well-priced version if you don’t need a narrow blade).
Enter the “double square” – a similar tool, minus angle adjustment.
Lee Valley has just released a small double square ($49.50) that comes standard with two 21⁄2″-long blades; one is 1⁄2″ wide, the other just more than 3⁄16″ wide, with a 3⁄32″-wide, 1⁄2″-long probe on one end for sneaking into the smallest of places.
The stock is dead-square to the blades, and the rules are easy to change – though the center pin (the rule catch) does rotate in the body. (It does not on the $140 double square from Vesper Tools, which comes standard with three blades and also includes a 45° reference bevel on the stock, where the Lee Valley one does not.)