From: djb@invalid.com   
      
   On 21/09/2024 20:06, Snag wrote:   
   > On 9/20/2024 5:51 PM, Snag wrote:   
   >>    I got the back plate finished for the 3 inch chuck and I'm a bit   
   >> disappointed at my initial testing results . I've measured .015   
   >> runout on a piece of 1/2 inch stock that I'm pretty sure is straight   
   >> . Might be the jaws since the chuck body indicates about .004 near   
   >> the face . These are the inside step jaws and the clamping surface is   
   >> not very long so that may be part of it . I'll be installing the   
   >> outside step jaws tomorrow and checking them - it came with 2 sets of   
   >> those , one which matches the chuck s/n and one that doesn't . The   
   >> inside step set I have installed do not match numbers ... aaahhh ,   
   >> what should I expect for a $10 yard sale purchase !   
   >>    Actually , it may be as simple as regrinding the mismatched jaw   
   >> sets to match this chuck . I have a little time to play with it , got   
   >> no "other people's projects" in the shop right now .   
   >   
   >   Further testing having been completed the chuck has runout with all   
   > 3 sets of jaws of around .007" . Chuck body is more like .002-.003 . A   
   > known straight 1/2" rod is not pointing  straight with the ways ...   
   > looks like it's time to set up the toolpost grinder .   
   >   So it looks like maybe a cheap chuck , though well made . Fit and   
   > finish are good , everything fits as it should and the scroll moves   
   > smoothly with all 3 pinions . Which brings me to a question - since   
   > there's more than one pinion is it going to make any difference which   
   > one I use ? Do I need to give 'em all 3 a twist when I mount a piece   
   > of stock ?   
      
   Does it have a pinion with a 0 next it? All my 3 jaw self centring   
   chucks have one and is supposed to be the pinion which result in the   
   minimum runout.   
      
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