1) Notching instrument 
Saw set is a term applied to various forms of a tool used in the tuning and sharpening of saw blades. The saw set is used to adjust the set, or distance the saw tooth is bent away from the saw blade. == Purpose == When the teeth of a saw are formed from the body, they are in line and the same thickness as the blade immediately behind them. A saw w...
• (n.) An instrument used to set or turn the teeth of a saw a little sidewise, that they may make a kerf somewhat wider than the thickness of the blade, to prevent friction; -- called also saw-wrest.
Saw'-set` noun An instrument used to set or turn the teeth of a saw a little sidewise, that they may make a kerf somewhat wider than the thickness of the blade, to prevent friction; -- called also saw-wrest . 
[n] - a tool used to bend each alternate sawtooth at a slight angle outward
noun a tool used to bend each alternate sawtooth at a slight angle outward