ROTARY TOOL HOLDER ASSEMBLIE

摘要

A rotary tool holder assembly comprising a collet (2) carried by a shaft (1). The collet (2) is moveable relative to the shaft (1) between a tool gripping position, in which an inserted tool can be gripped for rotation, and a tool release position. In some cases, the shaft (1) comprises a bore, an inner surface of which is shaped for contact with an outer surface of the collet (2). The shaft (1) and collet (2) are shaped such that when the rotary tool holder assembly is rotated at a predetermined high speed the shape of the inner surface of the shaft (1) substantially matches the shape of the outer surface of the collet (2). A friction reducing coating is provided between at least a portion of the inner surface of the shaft (1) and the outer surface of the collet (2). In alternatives, particular parts of the rotary tool holder may have a friction reducing coating.