Once you start working on fine joinery, you realize very quickly that success and failure is measured in 1000th’s of an inch. And how do you make such a measurement? With a pair of callipers. While accuracy to this degree may seem unnecessary in woodworking, if you are trying to join two pieces of hard wood (like maple) together and you are more than a 1000th’s off, it’s not going to work. I found that callipers with a dial on it make it easier to read and it saves you trying to count the little scribed lines. I bought mine at a surplus tool store, no need for one of the million dollar ones from Starret.