Abstract: A removable interchangeable thumb or finger grip insert for the thumb or finger hole of a bowling ball. The insert is generally cylindrical and hollow and is formed with a slotted resilient hollow bottom axial internally and externally threaded stud for threadedly engaging in the bottom of the bowling ball hole. A tapered adjustable wedging screw is engaged in the hollow stud for expanding it to tightly grip the bowling ball. The screw has a square bore engageable by a correspondingly-shaped L-shaped square tool bar. A spanner wrench tool is provided, the bottom of the wrench tool having a pair of spaced depending pins engageable in holes provided in the bottom of the insert for rotating same.