Setting mechanisms especially for tools for carrying out routing and like operations

A tool for carrying out routing and like operations on a workpiece, comprising:

• a base plate;
• a housing having means for driving a tool bit, said housing being connected to said base plate and being movable towards and away from said base plate for moving the tool bit into and out of engagement with the workpiece;
• a depth stop for adjustably limiting the downward movement of said housing relative to said base plate;
• said depth stop comprising a post extending upwardly from said base plate, a first collar of generally cylindrical form mounted on and movable along said post, and a second collar encircling and screw-threaded onto said first collar, the position of said second collar relative to said post limiting the downward movement of said housing relative to said base plate;
• said post having a rectangular cross-section with a toothed rack formed along one side of said post;
• said first collar having a rectangular bore through which said post is slidably and non-rotatably located, said bore having at least one internal tooth on one side thereof for engaging said toothed rack, and said bore having a larger dimension in the direction at right angles to said internally toothed side than the cross-section of said post in said direction to enable said first collar to be displaced in said direction relative to said post for disengaging said internal tooth from said toothed rack and enabling said first collar to be slid along said post;
• means for resiliently urging said internal tooth into engagement with said toothed rack;
• said first collar being slid along said post to set said depth stop approximately to a desired setting, and said second collar being rotated relative to said first collar to adjust the approximate setting accurately to the desired setting;
• and
• a scale connected to said second collar for movement therewith along said post, said scale having a portion disposed between said post and said second collar, and said portion comprising said resilient means.