Starrett Steel Combination Square with Square Head - 4" Blade Length, Cast Iron Heads, Hardened Steel, Reversible Lock Bolt, 4R Graduation Type - 11H-4-4R

Starrett's 6" inch combination square is regarded by many as a the best on the market. I haven't evaluated any of the other high end squares, but to my mind it is nearly flawless. Why do I think this?It is square, not kinda' sorta' square if you hold it right. I mean square to the point where you can't detect any light between a machinist's reference block and the body or blade even with strong backlighting. Your eye can see light from a 0.001" opening so you know the square is at least this square.You can tighten the thumbwheel using only one hand to achieve the squareness described above.The numbers and lines are engraved so they don't wear off. The engravings are deep enough so that you can put the points of your dividers in them to accurately set the distance between the points.The satin finish on the blade makes it easy to read.The "4R" marking system (1/8, 1/16, 1/32 and 1/64) is more useful than you might realize. It cuts down errors due to misreading the scale and is faster.Reinserting the blade after removing it from the body is easy. On some squares, this is a major hassle. On the Starrett, the protrusion in the body which holds the blade generally stays in place when you remove the blade. If it gets misaligned with the slot, it is easy to rotate it back to parallel with the body so you can reinsert the blade. The spring holding the protrusion has the proper amount of stiffness.Another good thing is that it is rugged. I haven't hit it with a hammer or put a torch to it, but it has suffered a lot of drops onto a wooden floor without damage.Why don't I think it is perfect? It will rust (like almost all steel) if you don't take care of it. By taking care of it I mean storing it dry, free of salt from sweat, and dust. Not a big deal, but this is a precision square so treat it with the care it deserves.A wise man once said, "When you buy quality, you only cry once." Do yourself a favor and buy this square.

This is one of those unique tools that lives in a special place in my cabinet. It reminds me of a different world where craftsmanship and engineering reign supreme. Why the superlatives? Because it is more than a very well made, very accurate, high-quality combination square: It is because when I take this tool in my hands, I FEEL (add emphasis) different, and I work differently because of it.Corny, you say? It's just a pricey combination square, you say? Perhaps. But for me, there are only a handful of tools in my collection that evoke an emotional response whereby their very use transports me back to my grandfather's shop, where I can feel the textures, hear the machinery, and smell the varnish, dust, motor oil and age. This is one of those tools. It makes me nostalgic for an age- real or imagined- before outsourcing and cheap tools, when quality was the norm. This combi square simply looks and feels different than many of my other layout tools, aside from being more accurate and precise than any of them. It looks... machined.Enough of waxing emotional. this is a high quality, precision tool that belongs in your tool box if you need that kind of precision (squaring-up your miter saw or table saw, for example) and can afford it. I notice that this is now going for thirty bucks more than when I bought it two years ago. Yikes. Is it thirty bucks better? I doubt it. But then, I'm devoting five stars to this tool in part because of how the quality makes me feel, not just whether it is worth the dough for something that is very, very square and well-made.Would I recommend this tool for someone just to use for framing houses or building chicken coops? No, I wouldn't, as there'd be less bang for the buck there versus other combi squares that are square enough and go for far, far less. I would wholeheartedly recommend this, however, for those who need a precise layout instrument that will last, that has smooth, well-engineered action, and is dead level, square, and straight... And that makes you feel good just by holding it.

I recently check accuracy on all of my squares. I had some redundancies and older pieces. I found that five of them, including two combination squares were visibly inaccurate. I now have several new squares, but have always had a combination square which I used consistently, so I bit the bullet on the cost of the Starrett. This square is truly impressive. It has some heft. The gradations are very easy to see. The slide is simple and easy to use. There is a feature with which, as you slide the head on the ruler, there are small bumps set at the gradation points that let you know how many gradations you have passed. This might sound silly, but I've found it extremely useful. The description on the Starrett website does not describe this and is in fact very weak, but the tools is a thing of beauty and it is always a pleasure to use and extremely well made tool.