Abstract: An insert is provided for varying the inside diameter of a hole in a device such as a bowling ball. The insert has a coaxial pair of telescoped tubes permanently joined together and a ramp section that is mounted at its base to a ring member. The ramp and ring are located between the telescoped tubes and can be rotated relative to the telescoped tubes. The inner telescoped tube is constructed of a flexible material, and its outside shell has a boss that separates two recesses. The ramp section decreases in thickness across its width. The cylindrical ring member terminates at its base in a slot. Upon inserting a driver into the slot means and turning, the cylindrical ring member and ramp section rotate relative to the stationary telescoped tubes. When the hole is at its maximum diameter, the ramp section rotates, with its thinner end first, onto the boss, thereby depressing a portion of the inner tube and constricting the diameter of the hole.

Abstract: An insert provides for varying the inside diameter of a hole in a device such as a bowling ball. The insert has a co-axial pair of telescoping tubes joined by a thread so that the tubes may be made longer or shorter by turning one of said tubes relative to another of the tubes. The inside tube terminates at its upper end in a conical wedge shape. A flexible tube or sleeve is cemented to the outside telescoping tube to be engaged by the inside tube as it telescopes. The flexible tube has a conical wedge on its outside surface for confronting the conical wedge shaped end of the inside tube. By turning one of the tubes, the two conical wedges advance toward or retract from each other to construct or relax the diameter of the flexible tube over a continuous range extending from a fully relaxed maximum diameter hole to a fully constricted minimum diameter hole.