Review on Accurate and Versatile: Exploring the Johnson Level Tool 406EM Combination by Eric Temple

Problems: 1. The major bearing surfaces of Johnson's combined squares (both large and small) are slightly concave/concave. This makes the angle unreliable unless you use it on perfectly straight, smooth and hard/hard edges and keep the full reference area of the combination angle on that perfectly machined shank. Tools and time.2. The slider is not fixed in the metric. The groove in the bolt is about 4-6 thousandths closer to the metric edge of the bolt. And Johnson uses the same pinch bolt for the 12" combo square as the 6" combo square, even though the slide is 20% narrower. The draw bolt barely has enough travel to lock the inch side. The metric side does not snap properly. This can be fixed by turning the clamp screw in the drill bit and hitting the bottom edge with the dremel. There are only a few thousand that need to be removed.3. Stamped closure is deformed. When you have OCD, you can spend hours trying to correct it. There's probably no way to flatten it out completely, but you can get it close enough to fake it on that 6-inch span. Miscellaneous: Metric/Imperial: You can only read this square correctly from one side. So you can use imperial or metric system. (if you have locked the metric system). On my other combination square, simply flip the square to read imperial or metric units. Reading the back gives a countdown of 6 inches / 15 cm. There are of course advantages and disadvantages. Stamped closure. The slide is a little hard to read as it is stamped and has no color fill. On the plus side, some of the slides are engraved very shallowly and could theoretically be unreadable if scratched enough. This slide can be read forever. Overall: This square might require a bit more tweaking to get it at its best than some other brands. But anything wrong with mine is fixable. Now this is one of my favorite places. Beautiful, light, attractive and as accurate as I will ever need. But I hope I won't do it again any time soon.