Front page of the .pdf shows a neat lumber gauge in action. It's designed to fit on your finger and allow rapid checking of common dimensions. You can still b

Front page of the .pdf shows a neat lumber gauge in action. It's designed to fit on your finger and allow rapid checking of common dimensions. You can still buy these...or, in this case, an excellent reproduction here: https://www.leevalley.com/en-ca/shop/tools/hand-tools/marking-and-measuring/calipers/58701-lumber-thickness-gauge?item=50K6301 https://www.leevalley.com/en-ca/shop/tools/hand-tools/markin...