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Poor Finish and Strange Helical Patterns
- Thread starter Jecheon
- Start date
Steve has a good point about the live center, and possible bad bearing. I would be trying it again with a dead center, and retest before going any farther with this.
Ive had a live center go bad, from to much pressure applyed, and it made a pattern simular to yours. If you dont have a dead center, then try a cut with out a center. Id be looking at all the possible things, before tearing into the spindle bearings.
When using centers, you should recheck, and reajust after you make a few cuts, heat will make things tighter.
Ive had a live center go bad, from to much pressure applyed, and it made a pattern simular to yours. If you dont have a dead center, then try a cut with out a center. Id be looking at all the possible things, before tearing into the spindle bearings.
When using centers, you should recheck, and reajust after you make a few cuts, heat will make things tighter.
I have seen something like it .Tried first to halve speed and and then to halve feed .The best remedy was feeding by hand.Disconnected tumbler ,stopped lathe and turned the leadscrew by hand.Torque was not uniform.Dismantled gearbox and leadscrew.Cleaned and lubricated.Problem gone.
Kind regards
Farfar
Kind regards
Farfar
Hi Guys,
Sorry for the long delay, but for interest the problem of the mystery chatter was solved. The main cause originated from stretched V-belts. The Regal is fitted with twin V belts and over time they had stretched unevenly. As the belts were different lengths is was causing vibration and I guess this resulted in fluctuations in the cutting forces on the work. For people with a similar problem, an easy way to see if the belts are of uneven length is to draw a chalk line across both belts; run the machine for a second or two and see whether the line is still continuous. On my lathe it wasn't. As a quick test, I ran the machine on one belt and the problem was gone.
On closer examination there was also a little bit of play in the saddle gibs which adjusted out with no problem.
Thanks for all the advice.
Pete
Sorry for the long delay, but for interest the problem of the mystery chatter was solved. The main cause originated from stretched V-belts. The Regal is fitted with twin V belts and over time they had stretched unevenly. As the belts were different lengths is was causing vibration and I guess this resulted in fluctuations in the cutting forces on the work. For people with a similar problem, an easy way to see if the belts are of uneven length is to draw a chalk line across both belts; run the machine for a second or two and see whether the line is still continuous. On my lathe it wasn't. As a quick test, I ran the machine on one belt and the problem was gone.
On closer examination there was also a little bit of play in the saddle gibs which adjusted out with no problem.
Thanks for all the advice.
Pete