Abstract: A deburring tool having an insert having four cutting edges such that the tool will cut in either direction of rotation is disclosed. The insert is pivotably mounted on a handle.

Abstract: A hand operated countersink has a shaft attached at one end to a cutting insert and at the other end to a handle, wherein said cutting insert is substantially of isosceles triangular shape. The insert has at least two cutting edges each disposed along an equal side of the triangle, one of the cutting edges being operative to cut when the shaft is rotated in one direction, and the other cutting edge being operative to cut when the shaft is rotated in the other direction. In a preferred embodiment, the insert has four cutting edges, two disposed along opposite edges of one equal side of the triangle, and two disposed along opposite edges of the other equal side of the triangle.

Abstract: The invention relates to fine adjustment means used with instruments which have to be finely aimed in a certain direction. The multi-directional fine adjustment unit comprises two discs held coaxially adjacent to each other by connecting means located along the axes of the discs and tilting means for tilting one disc relative to the other, wherein said tilting means are located in a circumferential annular track between the discs, and wherein said tilting means may assume any position along the track.

Abstract: A hand-held collet for holding a tool or the like within displaceable jaw pieces which are mounted on sprung rods accommodated within a hollow tubular handle.