I have a Pinnacle mill, combined vertical and horizontal, table size 750mm x 180mm.

Recently I acquired a decent spirit level, stuck it on the table, and of course it showed things were far from level in all directions. The mill is equipped with tapped holes at the corners, so I can fit jacking screws, but it sits on a floor which is timber, although very strong. It’s a wood lining, for insulation, on a concrete base. I could fit some 6mm steel strips across front and back and I guess- it is a guess - that the jacking screws would bear on these and the whole caboodle could be brought level.

My question is- is it worth it? I like a project and it’s about the right sort of thing, ie not too complex or expensive, but I suspect there’s not much to be gained.

Views, please.

If you have a levelled machine you can use a level or angle setting device clinometer etc on a job which has no way of using the bed to work off. If you are using coolant it should run off the correct way if the machine is level.

David

If its a digital angle box you can zero it on the wonky table and then simply set your work relative to that.

I'd say not worth the bother, more important that the head trams true to the bed.

All my machine stand on wood, one similar sized mill just sits flat on the bench two other similar size mills one of which is CNC came with leveling feet and were just set with a Stabila builders level on the bench that they sit on. The lathe sits on the wooden floor which was laid with similar level. Works for me.

Edited By JasonB on 22/09/2022 20:36:12

Well I would say yes, but only because I sometimes use “gravity” as a handy reference for some set ups. When I am not going for a very high level of precision, it is handy to use one of those electronic level gizmos on the work to indicate that you are more or less horizontal or vertical or at any desired angle.

I am also working on some tooling for cutting valve seats where I am going to use a circular spirit level located in the valve guide to indicate that the valve guide bore is vertical - if the mill is also properly levelled, I can assume that the valve guide is then aligned with the mill vertical axis......more or less.

If you set everything up from the table i.e. the mill only references itself, then it doesn’t matter.

Ian

Another thought.....if you were on a ship or in a space station orbiting the Earth you could still make things despite not being able to level your machines, so not essential. But whilst you are on the Earth it seems a pity to waste gravity 😃

I've never even thought about it let alone measured it, so for me it's of zero importance. The CNC mill sits on a welded steel tube stand. The base is shimmed to the stand so that mill is trammed. The manual vertical mill (Bridgeport) sits on the concrete floor but isn't bolted down. The head is trammed. The horizontal mill (A&S 2E) just sits on the concrete floor; at nearly 2 tons it's not going anywhere.

Andrew

Machines in a tool room will usually be levelled to a good standard and grouted in. It could be useful for some setups to be able to use a level knowing the table is level. In reality most people will never find it especially useful and unless you check before you rely on the table being level it may lose the original setup if the foundations move. This dry summer has played havoc with many roads so workshops are probably not immune from ground movement and machine levelling could be disrupted.

Mike

I gave that a lot of thought, so 1st thing comes to mind is a ship with a workshop.

My mill is level for coolant reasons and ease thereof(Not 100% accurate), if coolant design is to flow with mill table level, but I will not use that for any accuracy achivements, seeing the indicators will be more specific and accurate and more easy, than using spirit levels. Using spirit levels(Digital) you zero it and work relatively,

Chris,

Mike Poole’s comments are spot-on

The usual reason for setting the table of a Mill horizontal [which, for the avoidance of doubt, is not really the same process as ‘levelling’ a lathe] is to make it easy to set the workpiece using a sensitive spirit level.

The ‘uncertainty of measurement’ that goes with most digital levels would make a nonsense of this process.

MichaelG.

I think any reasonably flat and level floor would be good enough for a mill.

As Michael points out mills don't need 'levelling' in the same way as a lathe might to straighten the bed, and I've never set a workpiece with a sensitive level. Partly because I didn't know until now it was a way of working, but mostly because my mill is trammed relative to the table, not the floor.

Starting by levelling a structure is always a 'good thing' whether it's a house, factory chimney or machine tool. They're designed so the forces due to the weight of the structure itself and whatever loads are applied to it are transferred to ground without causing the structure to bend or topple over. When a machine tool is set up for accuracy, making sure it's level on installation ensures any further adjustments aren't distorted because the machine is tilted, which saves a lot of fiddling. But I doubt levelling is a priority in a home workshop.

Dave

Me neither, although I have a sensitive level; 0.0005" in 10" per division. If I want a top surface to be "level" I set it to zero with a cheapo digital level zero'd on the table, and then use a DTI to get zero movement as the table is moved. Using the DTI references the work surface to the ways, not the table, which I think is better.

Andrew

I have to agree with other comments, on the mill a sensitive indicator is the way to go. If you want to use a level and the mill has moved then everything has to be put on hold until the mill levelling is rectified. On a floor with any give then a heavy vice or rotary table with a large workpiece mounted in it will change the levelling as the masses are moved from one side to the other. A suitably sensitive level will detect this and it will soon become an annoyance.

Martin C

Levelling the mill - is it worth it?

IMO, an utter waste of time, cost and energy. Can’t be much more blunt than that!

Dave, Andrew, Martin

I only mentioned it because it was demonstrated to me by one of the tool-makers at KODAK, best part of 40years ago … IF the machine is suitably massive and stiff, AND the foundation adequate, THEN it can be a useful time-saver.

I have no intention of promoting the idea, I have simply seen it in use.

MichaelG.

My thanks for all those very useful contributions. I occasionally get seduced into a sort of mission creep, thinking I’d like to do things in the most swagger mode possible. It’s often (usually) a mistake and unnecessarily complicates things and doesn’t produce better results. I had been wondering if perhaps there was some advantage in accurate levelling of the table that I hadn’t realised, but it seems clear that, for me, there isn’t, so thanks again and I can stop shopping for 6mm flats.

Glad you did - most of my learning comes off the forum and the magazines. Still plenty more gaps to be filled!

Dave

Hi, when I made my stand for my Major milling machine, I included holes in all four corners for levelling feet, not so much for getting the table dead level, but for any unevenness of the floor.

I did use a level, but like JasonB, it was a Stabila one, which is about 600mm long. It's also easier than mucking about shimming to stop the machine rocking across two corners.

Regards Nick.

Having adjustable jacking screws is a great help to stop any rocking about, but its up to the individual whether to get it exactly level or not. Some mills are deliberately tilted to allow faster coolant draining. Both of the mills at the museum are fixed to the concrete floor using studding and chemical anchor resin. They are raised about 4" with wood and bolted. The relatively high centre of gravity is a factor, and they both are close, but not exactly level in either plane, so a cutter laid on the bed would not be in danger of rolling off. I have recently got one of those little square electronic levels to set things at an approximate angle. I do have adjustable angle plates with scales that have had their zero marks added by using a spirit level, I just matched the bubble deviation to that of the bed.

My mill has a concrete base with welded metal structure to make it higher so I don't bent my back too much, same with lathe, some advice I got. The mill is bolted on 6x 20mm bolts and the purpose of that was to get it level for coolant flow and a sturdy base, just the way I decided to do it. If it was not for that I would just placed the mill on the floor.

While on the subject of levelling, the lathe is another story, but there are lathes on ships too, so its more about the bed twisted than levelling, but theres coolant involved maybe too. The interesting thing is if you bolt a smaller lathe down to anything, you have a problem, then you must shim it and hope your surface bolted too is stable enough.
Bolting it may twist the lathe bed.....Something to think about.

I bought one of these box levels recently on a show, however it times out before I can set it up after zeroed for a comparison to make an adjustment, so that was that. I don't know if I open it up there may be aplace to disable the timeout. Maybe it was not the best type.

I would suggest levelling any equipment on a wooden floor is a waste of time. My whole shed expands and contracts with the weather so I’m sure this affects the wooden floor as well, even sat on a concrete base. I’ve not bothered levelling any of my machines over the years and it doesn’t seem to have affected my work. I suppose if you demand extreme accuracy levelling might well be important though, that being the case I’d mount through the wooden floor onto the concrete.