ewlsey
Diamond
- Joined
- Jul 14, 2009
- Location
- Peoria, IL
I'm chasing down the cause of poor surface finish on my engine lathe. It's a 16x40 geared head lathe, made in China. It's a stout commercial grade machine. Not a hobby home shop toy.
1045 material, 1.7" diameter, feed .014/rev, 700 RPM, .08 DOC on diameter.
Did some hunting. Cross slide is badly worn in the middle of travel, like .01" slop at the location where I was making this cut. So, obviously that's a huge issue.
I checked the spindle bearings at both ends with a pry bar and indicator. Seems good and tight both radial and axial. Runout on the spindle nose is basically 0.
I wanted to isolate the issue to the wear in the cross slide, so I put some bar clamps on the cross slide to hold the dovetail over and down. Then I took some more test cuts that way.
It's better, but certainly not good. If I use these same parameters in my CNC lathe, the finish is flawless. Am I asking too much? I'm OK with fixing the wear in the cross slide, but I'd really like to rule out other sources of the poor finish before I dive in.
Any thoughts?
1045 material, 1.7" diameter, feed .014/rev, 700 RPM, .08 DOC on diameter.
Did some hunting. Cross slide is badly worn in the middle of travel, like .01" slop at the location where I was making this cut. So, obviously that's a huge issue.
I checked the spindle bearings at both ends with a pry bar and indicator. Seems good and tight both radial and axial. Runout on the spindle nose is basically 0.
I wanted to isolate the issue to the wear in the cross slide, so I put some bar clamps on the cross slide to hold the dovetail over and down. Then I took some more test cuts that way.
It's better, but certainly not good. If I use these same parameters in my CNC lathe, the finish is flawless. Am I asking too much? I'm OK with fixing the wear in the cross slide, but I'd really like to rule out other sources of the poor finish before I dive in.
Any thoughts?