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spindle direction on cnc lathe

cuttergrinder

Hot Rolled
Joined
Mar 16, 2007
Location
Salem,Ohio
I know it is common for cnc lathes to run either direction while cutting depending on how the tool is set up. We have a large Leadwell lathe but it seems to cut better when the spindle is turning so that the tool pressure is pushing down on the turret rather than lifting it up. I did some checking today and the ways for the turret definitely have a little play when lifting with a bar. I know the gibs need adjusting but was just wondering if guys usually run a large cnc lathe so the tool pressure is down. The reason I'm asking is we are getting some cable drums for a crane to turn and groove for the cable. These are 20" diameter and 13' long so maximum rigidity is going to be needed. The grooves for the cable will be both left and right handed and the grooves have to plunge on the one end of the grooves but they have a runout groove on the other end. Just wondering if I should try to program so it is always pushing down on the tool rather than lifting?
 
I am more concerned with letting the chip fall away. Your play may be as a result of continually having force applied in one direction. From memory there is an alignment pin and that should remove play equally in all directions provided there is no wear. Same applies to a Curvic coupling.
 
I am more concerned with letting the chip fall away. Your play may be as a result of continually having force applied in one direction. From memory there is an alignment pin and that should remove play equally in all directions provided there is no wear. Same applies to a Curvic coupling.
I did a poor job of describing the play. The play is actually in x axis ways. I can lift the cross slide .010" with a bar.
 
I can lift the cross slide .010" with a bar.

You need to fix that! You got a lack of Turcite or a gib problem.

As far as rigidity, it depends on the lathe. Slantbeds I've owned don't seem to care. Larger conventional bed CNC's didn't like lifting the turret off the ways as much as pushing it down.
 
In that case you probably need to sort it out. But in the short term reverse the tool to compensate.
 
You need to fix that! You got a lack of Turcite or a gib problem.
Make sure it is the ways and not the thrust bearing or ball screw nut. I've seen quite a few problems where it was just the thrust bearings that needed replacement.
 
You need to fix that! You got a lack of Turcite or a gib problem.

As far as rigidity, it depends on the lathe. Slantbeds I've owned don't seem to care. Larger conventional bed CNC's didn't like lifting the turret off the ways as much as pushing it down.
This is a slant bed. I can feel an adjustment screw under the ways just like would be on a manual lathe but A manual usually has dovetail ways. This one has flat ways. Im going to check it out tomorrow.
 








 
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