Abstract: An adjustable work support that is received on an upright post of standard cross-sectional lumber dimensions. The support includes an elongated work supporting arm member. The arm is formed of an elongated channel having longitudinally spaced upright folded tabs. The tabs rotatably mount a workpiece holding roller. Furcations extend beyond one end of the channel. A spaced pair of cross members interconnect the furcations at elevationally offset locations. The cross members are horizontally spaced by a distance substantially equal to a standard cross-sectional measurement of an upright post. The cross members are arranged in relation to the channel and roller so they will bind against the upright post when the roller is held in a substantially horizontal position, and so they will disengage from the post when the roller is inclined from the horizontal position. Thus, the arm can be selectively positioned at any desired elevational location on the upright post.