Hi all,
I have lately turned a few reasonable size 'bowls' which are not balanced (see attached camphor laurel platter - wood courtesy of smife (thanks again) which still needs its finish).
camphor platter bottom view.jpgcamphor platter top view.jpg
This is approx 500mm x 200mm and was too big for me to use the tailstock for support.
Anyway, when turning both sides (faceplate to turn the bottom and chuck in expansion mode for the top) the lathe started shaking at around 300 to 400 rpm. I thought this was crap as I was never going to get anything like a clean cut so I sped up the lathe and could get around 800 with less shake than at a much slower speed and for the final part of the inside of the bowl I was up over the 1000rpm.
Does anyone have further knowledge / understanding of 'why is this so'? Everything I have ever read or seen says as soon as the lathe starts shaking to back the speed off but in this case I pushed through the shakes barrier. I am guessing if I had a big and heavy out of balance piece this would not be such a good idea :)
Any thoughts (especially on when this is safe) would be much appreciated and hopefully an education to many of us
cheers
Mick
I have lately turned a few reasonable size 'bowls' which are not balanced (see attached camphor laurel platter - wood courtesy of smife (thanks again) which still needs its finish).
camphor platter bottom view.jpgcamphor platter top view.jpg
This is approx 500mm x 200mm and was too big for me to use the tailstock for support.
Anyway, when turning both sides (faceplate to turn the bottom and chuck in expansion mode for the top) the lathe started shaking at around 300 to 400 rpm. I thought this was crap as I was never going to get anything like a clean cut so I sped up the lathe and could get around 800 with less shake than at a much slower speed and for the final part of the inside of the bowl I was up over the 1000rpm.
Does anyone have further knowledge / understanding of 'why is this so'? Everything I have ever read or seen says as soon as the lathe starts shaking to back the speed off but in this case I pushed through the shakes barrier. I am guessing if I had a big and heavy out of balance piece this would not be such a good idea :)
Any thoughts (especially on when this is safe) would be much appreciated and hopefully an education to many of us
cheers
Mick
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