Glenn Brooks
Aluminum
- Joined
- Nov 16, 2014
- Location
- Woodinville, Wa
Hi all,
Just discovered my new to me 1985 Southbend Fourteen can't hold decent tolerance on the X axis when making finishing cuts, e.g. Turning down the radius of a shaft. Spent the day making mucho test cuts. Short of it is:
- dial in .020" depth of cut on the cross slide, lathe cuts .024"
- dial in .010" depth of cut on the cross slide, lathe cuts anywhere from .014" to .019"
- dial in .005" depth of cut, lathe cuts .008" up to .015"
It seems to cut .004" to .006" over my selected depth consistently, with smaller cuts showing the greatest variation. SOmetimes twice what I dial in.
All of this even with the gibs tightened up and the carriage locked down to the taper attachment to prevent movement. Work supported by the tailstock. And also when making cuts with both HSS and Carbide tooling.
This looked like a nice tight machine. Good original paint. Gears show little wear. Bed is near perfect. The tool post is a stout QCTP. The spindle has around .001" of play, maybe a bit less.
I could understand dialing in a cut, and coming up oversize due to tool pressure. But consistently and widely turning over the dialed in amount has me baffled.
What could I look at to tighten this thing up? Iam sort of stumped.
Thanks
Glenn
Just discovered my new to me 1985 Southbend Fourteen can't hold decent tolerance on the X axis when making finishing cuts, e.g. Turning down the radius of a shaft. Spent the day making mucho test cuts. Short of it is:
- dial in .020" depth of cut on the cross slide, lathe cuts .024"
- dial in .010" depth of cut on the cross slide, lathe cuts anywhere from .014" to .019"
- dial in .005" depth of cut, lathe cuts .008" up to .015"
It seems to cut .004" to .006" over my selected depth consistently, with smaller cuts showing the greatest variation. SOmetimes twice what I dial in.
All of this even with the gibs tightened up and the carriage locked down to the taper attachment to prevent movement. Work supported by the tailstock. And also when making cuts with both HSS and Carbide tooling.
This looked like a nice tight machine. Good original paint. Gears show little wear. Bed is near perfect. The tool post is a stout QCTP. The spindle has around .001" of play, maybe a bit less.
I could understand dialing in a cut, and coming up oversize due to tool pressure. But consistently and widely turning over the dialed in amount has me baffled.
What could I look at to tighten this thing up? Iam sort of stumped.
Thanks
Glenn
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