Sterling Tool Works Cast Iron and Satin Chrome steel double squares are precise and balanced. This is an excellent tool for joinery, machine set up and thin pinned "London Style" dovetails. The Satin Chromed rules and blades have etched graduations that will never wear off, and are blackened for easy reading. We like the feel of the cast iron body of the Sterling Squares, and the knurled thumb screw blade lock is as secure and easy to use as any design we've come across.
The parallel sides and adjustable blade of a double square make it one of the most versatile layout and measuring tools in the workshop. Square to within .001" per Inch, Sterling Double Squares meet the government standard for machinist squares (GGG-S-656E), and easily exceed the precision necessary for airtight joinery, and basic machine set up.
The dovetail blade is included with the square, and is a feature unique to the Sterling Tool Works Double Square. The narrow blade is intended for checking squareness on narrow pinned dovetails. It's great for that purpose, but we've also started using it for a much wider range of tasks including checking narrow mortises, and measuring the depth of blind holes. The dovetail rule will also fit many but not all 6" combo-squares including squares from Starrett and Brown and Sharp (We list the dimension of the DT blade below) It will not fit 4" Starrett rules.
The Sterling Double Square is available with three blade combinations. Each includes a Dovetail blade in addition to the Graduated rule:
4” English/Metric graduations = .5mm, 1mm, 32nds, 64ths
6” English/Metric graduations = .5mm, 1mm, 32nds, 64ths
6” 4R graduations = 8ths, 16ths, 32nds, 64ths
Both the 6" and 4" squares fit easily into an apron pocket - which is important, because you'll want to use this tool every chance you get.
Dovetail Blade Dimensions:
.075" Thick, .329" Major Width, .091" Minor Width, 4" O'all length (1.3" inches of which is narrowed to the minor dimension)
Sterling Tools Works Double Squares and Blades are Made in the USA.