Abstract: A tool holding member is coupled to a driving or spindle member by a lug-and-slot universal type coupling member. The three members are held against axial separation by a pair of resiliently yieldable retaining rings which coact with the coupling member to allow the tool holding member to float radially relative to the spindle member. Means are provided for locking tools of various diameters in the tool holding member while providing a positive drive between the holding member and the tool.