What a monkey tool?Monkey tools are used to shoulder tenons and set materials for riveting . They are most often used in conjunction with spring swages of the same size. They are commonly struck but also can be used in the vise. Monkey tools are great for squaring up and upsetting shoulder on tenons. This one is for 3/8” diameter and is made a 1/64” larger than 3/8” to allow for heat shrinkage . #morticeandtenon #tenon #blacksmithing #frontstepforge #blacksmithtools #joinery #rivets | Front Step