A prosthetic valve crimping device capable of reducing the diameter of an expandable prosthetic valve having a support frame by at least 10 mm, comprising: a base and housing fixedly mounted thereto, the housing defining a central axis and having between six to twelve evenly spaced spoke-like guide channels, the guide channels each being at least 5 mm in length; a plurality of circumferentially arrayed nesting jaws axially and rotatably constrained by but radially movable within the housing, the housing flanking the jaws and defining the guide channels on both axial sides thereof, each jaw having at least one camming member that extends axially on each axial side into a guide channel, the number of jaws being the same as the number of guide channels on each axial side of the jaws, each jaw being substantially radially oriented and being formed of a single piece; each jaw defining an inner end that has a partial crimping surface which combines with the same on the other jaws to form a crimping aperture of variable diameter and having an axial dimension sufficient to crimp an expandable prosthetic valve, each partial crimping surface terminating on one side at a point that is constrained to move along a radial line as the jaw moves along the guide channel; each jaw comprising an outer head portion from which the camming member extends and an inner generally circumferentially oriented finger with a recess defined therebetween, and wherein each jaw nests within the recess of an adjacent jaw and the partial crimping surface is defined on a radially innermost face of the finger; two camming plates rotatable about the housing and having a plurality of spiral tracks (14a, 14b, 14c), which act directly on each of the camming members to displace them radially inward and move the jaws without any intervening connecting members; a manual actuator that rotates the camming plates and simultaneously moves the jaws in to reduce the aperture diameter by at least 10 mm to crimp an expandable prosthetic valve placed within the aperture, and subsequently out to release the valve after crimping; and a stop member that provides a physical stop to limit rotation of the manual actuator. a base and housing fixedly mounted thereto, the housing defining a central axis and having between six to twelve evenly spaced spoke-like guide channels, the guide channels each being at least 5 mm in length; a plurality of circumferentially arrayed nesting jaws axially and rotatably constrained by but radially movable within the housing, the housing flanking the jaws and defining the guide channels on both axial sides thereof, each jaw having at least one camming member that extends axially on each axial side into a guide channel, the number of jaws being the same as the number of guide channels on each axial side of the jaws, each jaw being substantially radially oriented and being formed of a single piece; each jaw defining an inner end that has a partial crimping surface which combines with the same on the other jaws to form a crimping aperture of variable diameter and having an axial dimension sufficient to crimp an expandable prosthetic valve, each partial crimping surface terminating on one side at a point that is constrained to move along a radial line as the jaw moves along the guide channel; each jaw comprising an outer head portion from which the camming member extends and an inner generally circumferentially oriented finger with a recess defined therebetween, and wherein each jaw nests within the recess of an adjacent jaw and the partial crimping surface is defined on a radially innermost face of the finger; two camming plates rotatable about the housing and having a plurality of spiral tracks (14a, 14b, 14c), which act directly on each of the camming members to displace them radially inward and move the jaws without any intervening connecting members; a manual actuator that rotates the camming plates and simultaneously moves the jaws in to reduce the aperture diameter by at least 10 mm to crimp an expandable prosthetic valve placed within the aperture, and subsequently out to release the valve after crimping; and a stop member that provides a physical stop to limit rotation of the manual actuator.