From: muratlanne@gmail.com   
      
   "Snag"  wrote in message news:vcnitb$1p0o6$1@dont-email.me...   
      
      I don't think this chuck has much wear . All the jaws look "new" but   
   that doesn't always mean much . I was told the original owner was into   
   woodworking , which doesn't necessarily require the precision needed for   
   metal working . By tightening all 3 pinions I have gotten it down to   
   average .004" , which is pretty close to my original equipment 5" chuck   
   . I can live with that ...   
   ----------------------------------------   
      
   I've considered using a bearing press disk set to measure the jaw inner face   
   runout at several diameters, to see if it varied due to wear or errors in   
   the scroll or was a constant error of the jaw faces, which might be   
   corrected on a surface grinder. A 3-jaw will grip evenly if the disk isn't   
   quite round.   
      
   For a 6-jaw that won't a stepped cone of plastic or a trued lawnmower blade   
   balancer could have enough flex to allow all jaws to clamp tightly, then   
   measure runout on the outer jaw surfaces and subtract their thicknesses, a   
   job for a spreadsheet.   
      
   I haven't tried this because I have 5C collets for precise work, a Set-Tru,   
   and lower cost 3 and 6 jaw chucks on 5C mounts that can be moved between   
   lathe and mill without unclamping the workpiece. Since I design what I make   
   some surface can usually be sized to fit a collet or mandrel for second   
   operations or later mods.   
      
   It appears that tubing thin and flexible enough to need a 6-jaw is also   
   flexible enough to fit a shaft despite jaw runout, for instance bearing   
   spacer rings. I haven't yet had a job that would require fitted pie jaws or   
   a pot collet.   
   jsw   
      
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