PDA

View Full Version : anotehr lathe leveling question (i know you're sick of them)



andy_b
03-18-2005, 07:17 PM
suppose you have the lathe mounted on a table, and the table has adjusters at the bottom of each of the four legs. suppose you level the table, then put the lathe on it and the tailstock end is about 1/8" low. is it acceptable to raise the tailstock end of the table to the point the lathe is just about level and then do the final leveling with shims, or should the whole thing be done with shims? i'm just wondering as it looks like the better and easier method would be to just raise the tailstock end of the table up, even though the table would be a bit unlevel. it isn't like things would be rolling off the table or anything. 1/8" over 6' isn't much of a tilt, unless you are a lathe bed. this table is flat and has no drawers or anything in it.

andy b.

egpace
03-18-2005, 07:51 PM
The purpose of "leveling" the lathe is to insure that the entire lathe bed has no twist, bow, or sag to it. In theory the lathe could be not "level" and be ok. Think of a granite surface plate, one end of the plate could be 1/8" low (running down hill), but the plate itself can be perfectly flat. In the case of the lathe, your ultimate goal is to make sure the tool bit dosen't fall below or rise above the center of the work piece when the carriage travels the bed.
Ed

QSIMDO
03-19-2005, 07:09 AM
I've seen several references to "leveling" lathes, etc. and they've always had me confused as the machinery on my ship was rarely if ever level!
Certainly, they were set up without twist on their deck pads but "level"?

Once per roll! http://bbs.homeshopmachinist.net//biggrin.gif

JeffG
03-19-2005, 07:32 AM
Andy,

I'm in the process of setting up my South Bend 9A, and have it on a bench with leveling feet, like your setup. I used the feet to get roughly equal contact with the uneven concrete floor.

I used the "2-collar" method to set up the Lathe. My bench is a 2" plywood top on heavy steel legs. I set the lathe on 4x4 aluminum pads, bolted it through the bench top (lightly at the tailstock end), made a test bar, and cut the collars. A couple of shims and cuts later, and my collars are equal, to the limit of accuracy of my cheap digital calipers (5/10ths).

No level required. http://bbs.homeshopmachinist.net//smile.gif

Jeff Greenblatt

Forrest Addy
03-19-2005, 09:54 AM
Looks like "leveling" is a confusing term for the newcomer to the home shop world.

How about: "aligned with a precision level?" Wordy, but maybe more descriptive.

Leveling in itself does nothing constructive for a machine tool. The object of leveling is not to "level" a machine tool but to ensure its flexible parts are not distorted by placement on an uneven surface. Leveling is merely a means of restoring the machine to the same condition as when its alignments and geometry were first established at the factory.

Thus leveling is a convenient means of returning a machine tool to its as-manufactured condition and incidentally for aligning (leveling) parts in a plane parallel to the machine's horizontal axes.

[This message has been edited by Forrest Addy (edited 03-19-2005).]

andy_b
03-19-2005, 10:04 PM
so then i guess the answer to my question would be it doesn't matter if the table is level, as long as the bed of the lathe doesn't have any twist.

andy b.