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- Joined
- 23 Jun 2004
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- 2,470
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- Macclesfield
Yes. It's a commonly used mechanism with inexpensive chucks to leave some clearance in the register for correcting runout. You would not need to do that with a premium chuck - my 3-jaw Bison the backplate is a very close fit in the register on the back of the chuck.so the alignment play is reduced by exploiting some play in the bolts onto the backplate.
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[if you didn't know sodastream has a controversy about their historic manufacturing site, and, still, workforce - occupied west bank settlements, political minefield bit like Dyson or Musk ]
When I first turned the backplate it was a dead fit, just managing to get it seated. There was 0.003" runout on the chuck taper which was unacceptable (there was also 0.003" runout on the test bar+collet so I assume the collet was not contributing much error). So the taper had been ground offset from the register on the back of the chuck. I shaved a thou off which wasn't enough to get it running true, so shaved more off to give even greater adjustment. Then I forced the bearing into the test bar while running with loose(-ish) mounting bolts which centered the chuck automatically. This is a common trick for centering workpieces generally (where you leave the chuck jaws not fully tightened) but I've not seen it used in this context.
I just finished de-burring those collets because every machined/ground corner was left razor sharp. That's how they save money - no proper finishing but they were dimensionally correct so usable. Very unpleasant to handle though in that state.