Regular Ripples w/ Power Feed on PM-1130v

Another 1130V owner checking in with a similar observation. I've been a little reluctant to share my thoughts on this since I'm quite new to the hobby, but I didn't want to let this thread to die since there's a potential of being an issue with the tool - either the design or, at minimum, the finish work.

I went through all my gibs and have them better adjusted, but what I'd suggest to anybody else with this issue is to look at the gibs on the (rear) saddle. I found a ton of slop in each of the four adjustment screws and getting these adjusted helped me out.
Even with these gibs adjusted, putting an indicator on the top surface of the saddle I'm able to see a thou or two of slop when I pull up on the carriage. It seems like this lathe would be better served with a front adjustable gib on the carriage instead of the fixed gib that it has.
 
Hello, I do not have a PM lathe but mine is a 1440 import. I have experienced this but only using certain spindle speeds. It is my belief that it is being generated at the headstock gear train and showing in the cut. Thanks.
 
Charles scozzari said:
Hello, I do not have a PM lathe but mine is a 1440 import. I have experienced this but only using certain spindle speeds. It is my belief that it is being generated at the headstock gear train and showing in the cut. Thanks.
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Interesting. Is there something one can do to narrow down the cause? What did you notice that leads you to think it's in the headstock?
 
It is all related usually to the leadscrew thread pitch. I found on mine the carriage wheel causes the carriage to rock back and further as it turns. It is not balanced so the offset weight of the handle causes this on my lathe.
Pierre
 
pdentrem said:
It is all related usually to the leadscrew thread pitch. I found on mine the carriage wheel causes the carriage to rock back and further as it turns. It is not balanced so the offset weight of the handle causes this on my lathe.
Pierre
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Not sure if I understand. This model has a lead screw and a separate power feed shaft. Under normal power feeding operations, why does the leadscrew factor in?
Are you talking about a PM1130V, or some other model?
 
zippyslug31 said:
Interesting. Is there something one can do to narrow down the cause? What did you notice that leads you to think it's in the headstock?
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Granted many things come into play, matial being cut, insert type, feed speed, depth of cut. If you have that covered like I feel I do the only other possibility is the spindle vibrating because of gear backlash or gears the are not cut properly. some speeds are not affected, some are. I compensate when needed by taking shallower cuts at slower speeds. I have also seriously considered removing the geartrain and using a belt system to the spindle with a variable speed control and a 3 phase motor.
 
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On mine I also have a separate leadscrew but the pattern matches it. The hand wheel is the problem on mine. That is what I am saying.
 
zippyslug31 said:
Not sure if I understand. This model has a lead screw and a separate power feed shaft. Under normal power feeding operations, why does the leadscrew factor in?
Are you talking about a PM1130V, or some other model?
Click to expand...
I would think if you took a face cut on a 3"or 4" round disc which means you eliminated the rack form the picture, with no sign of ripples that it just may be the problem. That contradicts what I said about the gear train vibration showing up in the rough finishes, but I feel that is my problem. If by chance ripples do show up on the face cut, it very well may originate then at the ( spindle ) headstock. Charlie.
 
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