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If you want your projects to come out square and true you need accurate setup tools. they do not get any more accurate than these, nor is there a better guarantee. Read on.
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INCRA Guaranteed Squares

When “close enough” won’t do

Text and photos by Tom Hintz

Posted – 9-15-2010

Regardless of the material used, being certain that your tools are set up perfect and the parts being assembled are at the needed angle remains paramount. Build a small error into what is supposed to be a 90 or 45-degree corner and the project will get farther and farther out of alignment with each subsequent corner. The good news is that when it comes to 90 and 45-degree corners the folks at INCRA offer their Guaranteed 45 and 90-degree squares – and they do not take the “Guaranteed” part lightly. All your end of the deal is remembering to use them!

The Basics

INCRA Guaranteed Squares are made from high quality aluminum and machined on ultra-precise CNC (computer numerically controlled) equipment. The blades are made from a single piece of this costly material to insure this unusual level of accuracy. The result is setup tools that you can use with confidence.

INCRA is confident as well and clearly demonstrates that with their very unusual guarantee. INCRA prints right on the packaging, “Angular accuracy is guaranteed to be less than 0.001” maximum deviation from nominal at any point along the full length of the blade.” While that kind of assurance is rare, INCRA goes a giant step further, printing on the other side of the box, “Unlike the more common two-piece design, our square will always stay perfectly square…even if you drop it.” Go ahead and look for that kind of confidence from other measuring tool manufacturers. We’ll wait for you here.

The blades (left) are one piece and CNC machined for the ultimate in accuracy. The notch (right) makes sure that a real 90-degree corner fits without holding the square out of alignment, even slightly.
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INCRA Guaranteed Squares are made from heavy material that allows a finished thickness of ¼”. That heft is part of why they can offer their no BS guarantee. Factor in the precision machining and preparation and you get a high-end tool. The blade widths are 1” on all of the 5” models and 1-1/2” on the 7” versions.

Useable Design

Each square has an alloy handle that brings the overall width of the base to ¾”. That extra thickness means that you can stand INCRA Guaranteed Squares on a flat surface and use both hands to make adjustments to bring tools or parts into perfect alignment.

You will notice a notch at the inside corner of the 90-degree INCRA Guaranteed Squares. That is not a machining fluke but rather an intentional design feature that lets the square fit over an outside 90-degree corner fully. It allows you to draw full-length layout lines and visually align parts all the way down to the body of the square.

INCRA Guaranteed Squares are available in 90-degree and 45-degree versions. Both of those are made in 5 and 7” versions. The 90-degree squares have model numbers of GSQR5 (5”) and GSQR7 (7”). The 45-degree models are G255 (5”) and G457 (&”).

In the Shop

For setting up machines, (left) the INCRA Guaranteed Squares are easy to use and dead on accurate, but only if you remember to use them! The body (right) is 3/4"-wide so the squares will stand on their own, freeing your hands for many alignment and adjustment operations.
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I have been using INCRA Guaranteed Squares in my shop for years and can attest that if you actually use them, your work will get noticeably better. Being sure of perfect alignment at each step of a project is not only reassuring, it helps eliminate an all-to-common mistake in the assembly portion of a project. Whether you use metal or wood your projects will benefit from using INCRA Guaranteed Squares.

The thickness of the body really is an important design feature. Most of the machines and tools we use that require alignment have a flat surface on which to base that setting. Being able to stand the INCRA Guaranteed Squares on the flat surface and use both hands (and other tools) to make the required adjustments allows us to be more precise.

I also find the wide body on the INCRA Guaranteed Squares helpful when checking the alignment of parts during assembly. There is often one side that I can stand the INCRA Guaranteed Square on and having that wide surface to stabilize the tool makes it easier to get a perfect corner.


INCRA even ships their Guaranteed Squares in a very nice, custom padded box. The box adds a little drama when you whip it out to show off your new squares. Oh, and it protects the squares very well also...
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INCRA Guaranteed Squares are a very well-made, thoughtfully engineered measuring/layout tool that comes with the best guarantee that I am aware of. When you want to get projects right, everything you use to create them must also be dead on perfect in terms of setup and/or alignment.

The forever accuracy and all around tough construction mean that with common sense use, the INCRA Guaranteed Squares will serve your shop needs forever and perhaps someone else’s forever as well. With a street price of $49.95 for the 5” models and $59.95 for the 7” versions (9-15-2010) the INCRA Guaranteed Squares represent a great investment in the accuracy of your shop from this day forward. Of course, if accuracy is not a major concern for you just grab something at the local big box. We won’t wait for you here though.

Visit the INCRA web site – Click Here

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