Expandable woodturning chuck

In combination, an expandable woodturning chuck and a substantially conventional face plate, said chuck comprising a generally annular member having two opposite end faces, and a substantially conical internal bore extending between said end faces, and said annular member being radially segmented into a plurality of portions the radially outer surfaces of which are shaped to grip the interior surface cavity of a workpiece;

• an annular resilient biasing means located exterior of, and substantially co-axial with, said annular member to urge said portions radially inwardly;
• a single frusto-conical plug located within, and co-axial with, said bore, said plug being rotatable relative to said bore, having a maximum diameter greater than the minimum diameter of said bore, and having a centrally located threaded aperture;
• and said face plate having a threaded shank secured thereto and extending away from said face plate, wherein one end of said chuck abuts said face plate, said chuck is rotatable relative to said face plate about said threaded shank, said threaded shank extends through said bore towards said plug and threadedly rotatably engages said centrally located threaded aperture in said plug, whereby relative rotation between said shank and said annular member draws said plug into said bore towards said face plate and thereby clamps said annular member against said face plate, the movement of said plug into said bore radially expanding said annular member to grip the interior surface of a cavity formed in a workpiece to be turned.