A specifically designed device used to bore, turn or grind jaws accurately under clamping pressure on power chucks. The Trueborer is infinitely adjustable within its specified clamping range, allowing fine adjustment for minimal skimming of jaws, which can also be through bored in one operation resulting in better T.I.R. of parts. It is available in three sizes covering chucks from 125mm to 600mm diameter.

The accurate and quickest way to machine your soft jaws




• Quick clamping of top jaws to produce a perfectly concentric bores or turned diameters
• Allows jaws to be bored or turned at the same clamping pressure required to hold the workpiece
• Only one operation even if through boring jaws
• Saves on jaw usage because of the adjustment allowing minimal skimming of jaws
• No time wasted looking for, or turning clamping rings
• One Trueborer can be used on many chucks
• For grinding, boring or turning of soft or hard top jaws