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Post by michaelclark on Sept 16, 2016 19:55:44 GMT
When I turn a bobbin stick round and put it in the chuck it wants to cut a different round can anyone help
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Post by Pete on Sept 17, 2016 14:15:03 GMT
Not sure I fully understand the problem, but I am guessing you have gone from between centers to chuck mounting... IF that is correct then I would suggest that either the shoulder on your wood is not exactly straight OR the lathe is not set up correctly.
To check the lathe, put a center point in both the head stock Morse taper and the tail stock bring them together then check the alignment points should meet perfectly. Then if you have one mount a center point in the chuck and do the same test any discrepancies need to be investigated and resolved.
If it's the shoulder on the timber that isn't straight that is down to you I find with 2 pairs of "identical" prescription glasses my perception of parallel and 90 degrees varies quite a lot, depending n which pair I am wearing (not sure either is correct!).
Best solution (After aligning the lathe) is to leave the center point mark in the end going to the tail stock, and use that to make sure its all lined up before finally tightening the chuck
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Post by michaelclark on Sept 17, 2016 19:40:20 GMT
Thanks for reply, I have checked the points meet on drives on the lathe and have checked on callipers that I am turning parallel but when I transfer from centres to the patriot chuck I need to skim again to get the round and I don't think I should have to do this.
Michael.
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Post by Pete on Sept 18, 2016 1:42:30 GMT
No, you shouldn't I was advised that despite the 4 jaw segments don't need numbering, on the Patriot Chuck its a good idea to tighten them on a known round when setting new jaws to the chuck.
I would normally leave a mm or two when switching from points to chuck mount to true up again, but that's mostly because I will rough out a dozen on points prepping for chuck mount then switch over and finish in the chuck but I would expect the centering to be right.
Do you have a chuck mount steb or 4 point so you can check alignment of the chuck?
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Post by michaelclark on Sept 18, 2016 16:23:06 GMT
Thanks for reply Pete I've just tightened stebcentre into chuck and now the centre in the chuck revolves around the tail stock centre in an egg shape which I can see is the same thing I am getting on the wood. Question is now can I get out of this or do I send it back also if I tighten jaws fully closed3 go tight and 1 I can get a steel rule between regards Mike
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Post by Pete on Sept 19, 2016 13:10:44 GMT
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Post by Rob on Oct 12, 2016 6:41:00 GMT
Just as an aside, my first steb centre was out of true and had to be changed so don't exclude that possibility. I also had a brand new chuck that was out of true too so things you wouldn't expect to have to check are sometimes worth keeping in scope when you're looking for a gremlin. The chuck wasn't a Sorby one but it was an expensive "made in England" chuck. The company changed it with good grace and the replacement is spot on but the salutary tale is worth mentioning I think in case you miss those components from any diagnostic measures you're taking.
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