An assortment of plain steel woodruff keys from The Hillman Group. Woodruff keys are semi-circular keys that are commonly used for mechanical applications. It fits in a half-moon shaped slot, in a shaft, leaving the flat side of the tab exposed. They are designed not to function when excessive force is placed on the shaft. Variants in this assortment run 1/16" thru 5/16" in thickness. Full assortments of #811 contain sixteen (16) refills comprised of Hillman item numbers #812 - #827.