Large lathe levelling

[Weedy64]

I know this has been beat to death in general but the lathes in question are usually 40" or less in length.

I have a Monarch 612 25x144, 16000lbs. Is there a procedure somewhere that deals with large lathe alignment (its large to me). It has a 4 adj. feet headstock, a 4 adj. feet tail pedestal and 2 ea. - 2 adj. feet center pedestals. I have watched videos etc on smaller setups but am a bit unsure if it pertains to mine.

Im good with the 2 collar test and the align. of the tailstock to the headstock. But what/how do you test when the tailstock moves to the other end of the lathe 10+ feet away.

Initial level: Where do you start? 2 headstock feet and single point at the tail end like smaller ones.

I have a Starrett 98 and a 199 is that adequate or do I need someone with optical or laser?

or not the right forum for this?

[Harold_V]

There's no reason why you can't level the lathe properly with the 199 level, but I'd advise against the 98. It's not anywhere near the required degree of precision. All depends on what you expect from the machine, though. The 98 would be better than nothing.

Start by getting the headstock area level. Move to the tailstock area, then the center. You most likely will have to revisit each position, ensuring you haven't made unwanted changes when leveling the next location.

Key, here, is getting the bed straight. How level it is isn't all that important, but by getting it level in both directions, you won't have to interpret error. Your objective is to get the bed straight. Minor error, when working between centers, would be corrected by tailstock adjustment.

H

[GlennW]

I made this to check my lathe bed.

[John Hasler]

Glenn writes:
>I made this to check my lathe bed.

I like that. It deals elegantly with the fact that the top of the v-way is not the reference surface and detects twist without needing to literally level the machine front to back. I think I'd put a lapped plate with a dimple in it under the ball, though. The ball will tend to pick small irrelevant variations. A three-legged version could check for longitudial sagging or bowing as well.

Of course, I have neither a machinist's level nor a machine large enough to justify its use...

[John Hasler]

Weedy64 writes:
> I know this has been beat to death in general but the lathes in question are usually 40" or less in length.

What's it going to be sitting on?

[earlgo]

My friend who used to move factory equipment for a living preferred to put down a thick felt mat on concrete and then a 1" steel plate and then put the lathe or mill on the plate. The felt took up a lot of irregularities and the plate provided a secure place to bolt the machine to. In your case, the use of a 12' long 1" plate might be difficult to deal with, so you could use smaller sections under your support points.

When the Cincinnati Milicron people came to Teledyne-Oster in 1986 to install a T-10 Horizontal Mill, they dug a 3 ft deep hole in the middle of the floor and poured in an isolated block of concrete with integral, but floating, hold down bolts to hold the CNC machine in place. (This was to isolate the machine from the punch press department machines.) Probably not cost effective for you.

Good luck.
--earlgo

[Weedy64]

Yes, plates....I forgot that detail.

The floor is +30yr old concrete of unknown thickness in a building in an old gravel pit. There are 4 ea 3/4" flame cut plates, the full size of each pedestal, head-stock and tail-stock. The 12 1-1/4 jack-screws all seat into OEM 3/4" x 5"dia ci disks that sit upon the steel plates. I do not plan to bolt it down, but there are holes in each disk to do so if I find it necessary.

Just a 4x4 3/4" plate is plenty to deal with. The others are manageble by hand.

I will probly construction adhesive the disks down to the plates to keep them from skating under vibration

[Weedy64]

My lathe is 12ft from a mechanical steel planer. They are on different slabs but not isolated to the level of T-O as above, I have thought about isolating the planer but I think a change from mechanical to hydraulic is in order first and that should soften its vibrations. I hope. I certainly do not mill anything important if the planer is running as I can feel it change direction through my boots.

[spro]

I think a laser in the center of the head spindle would be cool. You might want to use crotch center or a flat at the tailstock. Each section is leveled independently but the laser would show the twist or ramp, as the tail is moved across the section.

[neanderman]

Dang, that's a big lathe... We need pictures!

LeBlond recommended a minimum 6" thick slab to set even their short lathes on. Monarch is still around; you might drop them an e-mail with any questions.

[spro]

I would like to see how this goes. There are all types of newer laser levels. They scribe 3 dimensions, which used to be expensive.
I was thinking of the earlier lasers which could be colleted or chucked up to run true. Simple stuff within 50' and not something made for 10 miles and overheats. Just another register above the bed ways.

[Weedy64]

The floor is certainly not flat.. but so far the 3/4 plate just conforms to the floor with weight on the jacks-screws. A lighter lather could rock but this one bends the plates.. so far. I cannot slide a thin steel rule between the plate and the concrete anywhere near the jack-screws.

I"ll try n some pic from the tail end if the lighting is good.