A retention assembly for connecting a base to a tool having a shaft includes a shaft engagement socket defining a shaft receptacle configured to receive the shaft; a retainer configured to secure the shaft to the shaft engagement socket, the retainer having a body with an opening that can receive the shaft; and at least one finger extending from the body, defining a sliding surface, and being configured to contact the shaft. The sliding surface can contact a ramp on the shaft retainer socket, and the retainer can translate relative to the shaft engagement socket, such that when it is translated toward the shaft engagement socket, the sliding surface slides along the ramp and causes the finger to move away from the shaft, and when the retainer is translated away from the shaft engagement socket, the sliding surface slides along the ramp and causes the finger to move towards the shaft.

A tap holder having a simple structure and high runout accuracy is provided. A tap holder includes: a body having a collet holder hole having an opening toward distal end; a tap collet received in the collet holder hole, the tap collet having a tap mounting hole located at a distal end portion, and a sleeve hole located at a basal end portion; a torque transmission mechanism that transmits rotation of the body to the tap collet; a first elastic body disposed between the body and the tap collet to urge the tap collet toward distal end; a sleeve disposed to the body by received in the sleeve hole to prevent the tap collet from slipping off toward distal end; and a second elastic body disposed between the sleeve and the tap collet to urge the tap collet toward basal end.