# YANLLQ (yet another newbie lathe leveling question)



## iconoclast (Oct 16, 2009)

I hate to post yet another newbie lathe leveling question, but I'm frustratingly close to getting this thing level (that being my only real reference point for achieving straight/untwisted) yet I've got two problems I can't seem to find a solution for. 

I have the machinist level that does 0.0005" per 10" span, and I have it calibrated so that turning it 180 degrees shows the same reading.
I have 1-2-3 blocks that boast parallel within 0.0001", flat within 0.0001" and square within 0.0001" and I'm using them to level based on the flats of the ways and not the tops of the V part of the ways.
I don't have the luxury of leveling screws, but if I have to hoist this thing up yet again to adjust the shims I'm going to seriously look for a way to attach some. Nevertheless, I have the thing shimmed such that along and across the ways are all level, according to the above mentioned equipment, at all four corners. Just for good measure (no pun intended) it also shows level (along and across) in the middle (roughly half way between the headstock and the tail).

So far so good. Then when it's time to tighten down the bolts, everything goes to $#!+. 
Specifically, even slightly tightening any of the bolts make the rear (furthest from the operator) ways seemingly bow in the middle. That is, along the rear ways near the headstock the level says the tail is too high (two to three bubble lines), but along the rear ways near the tail the level says the head is too high (one to two bubble lines). Around that time placing the level across the ways in the middle will suggest the rear is too high (easily two bubble lines). 

That bowing problem occurs even while keeping the head and tails mostly level across the ways, but that brings me to the second problem. The tailstock end has two bolts, one on the front side foot and one on the rear side foot. (The headstock has four of it's own.) The bolt on the front side of the tail will become tight with the bubble only moving one line towards the back. With my fingers I can "tighten" the rear tail bolt such that it moves the bubble three lines toward the (tightened down) front, and yet it still isn't what I'd quite call "finger tight". Presumably, I could shim the rear tail such that it's out of level when the bolts are loose but levels in when the bolts are tightened, but that seems just wrong somehow, and I don't know if that just compounds some other wacky twist that will cause other problems. (Not to mention any interaction with the rear-ways bowing problem mentioned above.)

I've searched the web, read through numerous accounts of lathe levelling and theories regarding the pros-and-cons of adding twist for straighter cut, dissection of the strengths and flaws of RDM, the physics of using lathes on ships, and torn out some more my hair. Yet the closest thing I could find to anything relevant was one old-time big-lathe installation manual that suggested that shimming the outside edge of head and tail equally on the front and back could help correct ways that bowed up in the middle (presumably equally front and back) and vice-versa (inside edge of head and tail for ways that bowed down in the middle).

Incidentally, for most of my newbie machinist questions thus far, a google search returns useful results from this cpf sub-forum more often than any one of the dedicated machinist sites. Who would've guessed? Anyway, that combined with the fact that I already have an account here means you all get first crack at helping me. Please?


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## Torque1st (Oct 16, 2009)

When you tighten the bolts you may be compressing the shims and twisting the lathe bed. Or you could be applying a lever to the shims depending on their location and configuration. Some machine leveling feet are probably your best bet.

Once you have it level then making adjustments for taper are in order.


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## gadget_lover (Oct 16, 2009)

It would seem that if it is bowing when you tighten the bolts, then the feet are not machined flat and on the same plane or the surface you are putting it on is not flat. Or both.

I'm not sure how to fix that. 

Daniel


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## precisionworks (Oct 16, 2009)

> Some machine leveling feet are probably your best bet.


+1

Even with leveling feet, it's a touchy-feely job. 


Mason levelers under the Delta-Rockwell surface grinder. 4" diameter with 5/8" bolts.






El Cheapo leveling feet under the South Bend 10-K. Each threads into solid round stock 1.5" diameter, which is bolted under 2"x2" square tube that gives the lathe a larger footprint - nice when turning out of balance parts. The square tube & round stock raise the center height to the correct level for me.






If you keep trying to level with shims, you'll probably take up needle point instead :mecry:


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## Atlascycle (Oct 16, 2009)

How big of a machine are we talking about here?


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## iconoclast (Oct 16, 2009)

Right now leveling feet seem like a nice improvement. Especially considering that even once I get the thing level, I'll someday have to re-adjust it (shudder). However I'm not entirely clear how to get from here to there.

Sorry, I should've mentioned in the first post that this is one of the ubiquitous Grizzly G4003G machines. So the size is on the order of a 12x36.

Right now the lathe is bolted to the stands, which are in turn bolted to the concrete floor (as recommended by the manufacturers instructions). 
Neither the stand nor the lathe have threads where the bolts go through their feet. The bolts through the lathe feet thread into the top of the stands. Bolts sticking up from the concrete floor pass through the stand feet and have nuts to tighten down the stands. How and where exactly would the leveling feet attach?

The default height of the spindle line seems to be a reasonable working height, but I'm afraid that adding a few inches (when I say "few" I'm looking at precisionworks photo of the 10-K) might be problematic for actually using the machine. How might I attach these leveling feet so as to minimize adding additional height to the overall assembly as much as possible?

What should I look for in leveling feet? I presume something more than "flat on one end and threaded on the other" is in order?

For what it's worth, both the instructions for the machine and other anecdotal advice on the web said the stands should be "approximately level", and then the machinist level should be used to fine tune the level of the machine itself. As such, the stands are completely "carpenter level" both individually and across the space between them. (As you might expect, I don't have a machinist level that's long enough to bridge the 34" between them.) This seemed to make sense at the time, but thinking of the mating surface as acting like a lever when the bolts are tightened starts to make some sense of the behavior I'm seeing. I'm not really sure what to do differently there, but I'm hoping that a suitable plan for leveling feet will compensate for it?


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## gadget_lover (Oct 16, 2009)

It's interesting that the leveling feet displayed here (for most of them) do NOT actually fasten the machine to the floor. It instead simply jacks the machine up from the surface it is resting on.

In Iconoclast's case, it might be that the lathe needs to be bolted to the cabinets, then the cabinets need to be leveled ( in all planes ) to level out the lathe before bolting them to the floor.


Daniel


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## precisionworks (Oct 16, 2009)

> How might I attach these leveling feet so as to minimize adding additional height to the overall assembly as much as possible?



Look at the design of a machinery mobile base, where the casters are mounted on bent tabs that allow the machine to sit as low as possible. The same design should work for your lathe.


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## Atlascycle (Oct 17, 2009)

look at these from McMaster Carr, 60915K74 they will do what you want without adding to much height.

Jason


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## precisionworks (Oct 17, 2009)

Jason, that's a nice looking mount. I really like the way that the machine only has to be raised up 1.5" to slide the pad underneath & then the bolt threads in from the top side. With the one piece Mason Mount, the machine has to be raised about 5" to insert the bolt.


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## 65535 (Oct 17, 2009)

I believe the proper shims to use for level machinery are flat shim stock, angled shims are good for aligning simple things, but the angle of the surface makes for uneven pressure and a nightmare when you tighten down.


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## Atlascycle (Oct 17, 2009)

I have the same style of mount under a 300 ton capacity stamping press that weighs 80000#s. Very easy even inder a machine that heavy.


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## iconoclast (Oct 17, 2009)

ok, so if I understand this right... 
I grab eight feet like the ones Atlascycle pointed out. Pull the shims out (don't worry, they're not angled shims) from under the lathe and bolt it directly to the stands. Remove the bolts from the concrete floor, and chock them up to a learning experiance. Slip the new feet under the stands, resulting in the whole thing raising by about 1.5" + the height of any leveling adjustment. If that turns out to be too high, I have to rig up something with offset attachments like in precisionworks picture. 
Then do the whole leveling dance again, only now adjustments are made by turning the bolts that go through the stands feed into the leveling pads. The extra two adjustments on the tail end (four feet on the tail-end stand but only two bolts from the lathe feet on the tail-end into the stand) would mean more things to adjust properly, but with the advantage of being able to rule out (or at least adjust out) any lever effects resulting from how the lathe feet mate with the top of the stands. 
Am I on the right track or am I missing anything?


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## Torque1st (Oct 17, 2009)

I believe you would still need shims between the machine and the pad for the McMaster units specified. If you go to the McMaster site you may be better off with a mount similar to #60855K54 but sized appropriately. It has an adjustment nut for leveling.

Divide your machine weight by the total number of mounts used and go with the next size mount above that figure.


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