A guide assembly, or rip fence, supported by guides of a table saw includes a clamping apparatus having locking mechanisms located at each end of the guide assembly. Each of the locking mechanisms is independently adjustable to provide accurate and repeatable positioning of the guide assembly with respect to the table and with respect to the saw blade with self-alignment and desired force. An adjustable locking self-alignment spring provides for self-alignment of the rip fence with respect to the blade.