underhammer

Updated: May 5, 2025

The first action gave the blow with more direct force than the second, which had the notch upon what is called the underhammer, but was defective in the absence of any means to regulate the distance of the "go-off," or "escapement" from the string. In the second action, a small check before the hopper is intended to regulate it, but does so imperfectly.

Various - Scientific American Supplement, No. 385, May 19, 1883