Starrett Steel Inch Reading Double Square with Hardened Graduated Blade - Ideal for Machinists, Toolmakers, Patternmakers - 6" Blade Length, 4R Graduation - 13C

This is a beautiful, precision tool, and the first Starrett I've ever held. Many years ago I bought a Swiss made Tesa dial caliper and one of their micrometers after the original owner passed away. Those were my first introduction to precision tools, and they made a strong impression, how critical accuracy is and how affirming they are to use. For years I've been getting by with a low quality combination square and my Incra guaranteed square, but the former was cheap and the latter doesn't have any measuring marks.After reading the comments and studying the options, the choice to get a Starrett 6-inch Double Square was fairly easy. Like one fellow said, cry once but smile the rest of your life.All of the edges are perfect. It's as square as I can tell when holding it up to my Incra to check. If I get a chance to put it on a granite reference block, I'll update this. I was happy to find the blade is flat, and not a single burr anywhere. The movement is precise when the screw is loosened. It slides with exactness and no slop. It locks firmly without excessive torque on the screw. And there is almost no gap between the blade and the head.I am inclined to buy American tools that are the finest quality to help support my neighbors, and I was really happy I found the inspection certificate in the box, showing it was made in Althol, Mass.Here are some anecdotal measurements taken with a Mitutoyo 6" Digital Caliper and a Tesa 1" micrometer, where I'll note the error based on the certificate that came with it or the usual 1/2 the smallest increment. I wouldn't trust those with my life, but I do care for these tools as best I can.Blade Length: 5.9995 +/- 0.001"Blade Width: 1.0008 +/- 0.00025"Blade Thickness: 0.0814 +/- 0.00025"Head Length: 3.601 +/- 0.001"Head Width: 1.1845 +/- 0.001"Head Thickness: 0.5870 +/- 0.0025"Blade to Head gap: < 0.0025 (my smallest feeler gauge)I have one small regret. The only choice was the shiny blade that scratches easily and is harder to see under work lights than the stain chrome one, but I can still buy that separately. I give it 5 stars.

A bit of a luxury buy for me, but it has come in handy. Not a lot of cheaper brands of this type of square are available, especially with this level of consistent quality. Easy to adjust, smooth action, and very square.

High quality. Expensive and worth it.This is a double square - meaning the blade can slide and be fastened as needed. It's already difficult to find a good square. It's amazing that they can make a double square, which stays square. Anyways, that's what you're paying for.I use this tool for my woodworking hobby. Being able to quickly move the head along the blade means I can lock in a specific measurement and easily make repeated measurements by holding pieces of wood to head's side. This seemingly simple ability shines in many areas.One example is using the planer to get to a finish dimension. All I need to do is first set final size on the double square. After each set through the planer, simply hold the double square to the piece and feel if the blade matches the thickness of the wood. Checking by feel is immediate. Not there yet? Send it through again. There? Stop and move on. So simple. The alternative is to painstakingly measure after each pass, straining your eyes and running the risk of forgetting or making a mistake.This quality tool is expensive. And it's worth it. It saves you time. That itself should sell you on it. It is also built to last. How long? I'm not sure =)

Well made tool that I will pass on to my son. I was using a square from one of the big box stores. It was OK for construction, but didn't have the accuracy I needed for precision measurements in making fine furniture. About a month ago, I bought a double square (I won't say the name) that cost 30% less than the Starrett. I thought I was getting a good deal. I was wrong. The fit, finish, and overall quality wasn't there. The blade rattled in the handle. I sent it back the next day. I ordered the Starrett and when I received it, I knew it was worth it. Just holding it in your hands, you can feel it is a quality tool. The handle is heavy cast iron. Well machined. The thumb screw turns with little effort and doesn't get stuck - the threads are well made. The blade is non-glare and easy to read. The 90 degree angle of the blade and handle are dead accurate. Well worth the money.

Square out of the box, checked against 70 year old Starett. The rule move smoothly and is easy to read. Ii

This is my second Starrett square (I also own the larger 12-inch square with the 45 degree angle). I bought this to replace a small Crown tools try square that was, well, not at all square. I actually used that tool for a long time before I finally realized it wasn't true when I edge jointed a thick board by hand. That'll teach me to thoroughly check out stuff that I buy before use! Since there's no adjustment possible, that tool is now a brass and rosewood paperweight...Anyway, the Starrett is an excellent tool. It's perfectly square, at least to the limits of my ability to measure (by drawing a fine line perpendicular to a straight edge and flipping the square over to look for parallel). Adjustment is smooth. It's a good replacement for a fixed engineer's style square, and certainly accurate enough for woodworking. It's pricey, but you get a top-quality American tool, obviously made by people who care, that will last forever. That's a heck of a lot better than buying cheap junk that will ruin your work and be discarded.

I bought one of the cheaper squares that was rated as being "just as good as a Starrett". Don't believe it, buy the Starrett. You will not regret it.