Don’t follow the temptation to cheap out and buy a cheap combination square. Because, like me, you will eventually have to replace it because of its inaccuracy. If you want your joinery to fit perfectly, then you need to scribe it accurately with precise marking tools. Unfortunately there is really only one company (that I know of) that makes a super accurate combination square. But fortunately it is amazing, and I use it daily. I’ll talk about it in-depth in the Layout & Measuring Tool Buying Guide.