Abstract: Precipitation hardenable stainless steel endodontic files and methods for their manufacture, wherein the most preferred precipitation hardenable stainless steel is 17-4PH and aging is preferably not one of the manufacturing steps. Precipitation hardenable stainless steels used in embodiments of this invention are iron-chromium-nickel grades that have the desired properties of flexibility, strength, hardness, wear resistance, stiffness, resistance to permanent deformation, resistance to variable torque, and biocompatibility for endodontic files.

Abstract: A holder for small instruments such as dental instruments, comprises an inner member and an outer member both of which are figures of rotation. The outer member has a conical recess in its upper portion and a cylindrical recess in its lower portion. The inner member has a cylindrical lower portion by which it is secured in the cylindrical recess of the outer member, and has two truncated conical portions one above the other, the lower of which forms a relatively narrow conical recess with the outer member and the upper of which is of reverse inclination to the inclination of the conical recess of the outer member so as to provide a tapered entrance recess into the lower recess. The lower recess forms an angle of about 7.5.degree. with the axis of the holder.