Leveling a Lathe

Too much fuss is made over levelling of small lathes. Unless there is large weight involved it is not critical.

As pointed out above, lathes on ships at sea turn out perfect work. I have a couple of model engines entirely made in a ship's engine room at sea and they have run perfectly for 50 years or more.

More important is the bolting down to the bench or floor of the small lathe.

Put it on the bench and stick feeler guages under each mounting foot. Then put shims of correct thickness under each foot as needed. That way, when you tighten down the mounting bolts they won't pull the bed out of line.

Ditto when bolting the bench to the floor, which should be done first.

Hopper is right.

It would save a lot of time and effort if the words 'Leveling' and 'Lathe' were not used in the same sentence. A spirit level (or some fancy laser alignment device) are just one of many tools that might be used in the setting up of a machine tool.

A lathe has to be reasonably 'level' otherwise the tailstock might slide off the end of the bed on to the floor! There are many 'slant bed' lathes in industry, not what you would call ideal for checking with a level yet they churn out millions of very high precision parts every day.

With a lathe like a Myford (nice flat top surface) a precision level is a good tool to check the the bed has not been distorted when it was bolted to the stand, but it would be useless on anything smaller (like a watchmakers lathe!). Machinists precision levels really come into their element on large machines where (if the machine is level) are used for setting up the workpiece.

As regards deliberately twisting the bed in order to ensure parallelism when turning long items the level is not much help, as the only sensible procedure is trial and error.

Thats my £0.02 anyway.

I don't know how many more times it needs repeating on this forum, but when referring to lathes and other machine tools, 'level' means 'flat' (planar) or without twist.

So as long as the bed isn't warped once installed (level), the lathe doesn't care if it's on land or sea or even stood on its end, it'll still turn parallel to close limits.

Martin.

Hi there, all,

I'd like to pour a little oil (Nuto 32? ) on these troubled waters.

My Concise Oxford English Dictionary includes the following for 'Level':

"8. vt make level, even or uniform." (My emphasis) This would seem to me to legitimise use of the term 'levelling' for adusting a lathe bed to be free of twist.

'Level' has a lot of other meanings, many to do with being horizontal, but they don't invalidate those I've emboldened above. Context is everything!

Best regards,

Swarf, Mostly!

I have one of my Myfords set up exactly as Micheal Williams describes.

I needed a new bench, made a substantial one out of wood, the top is made from 2 1/2" strips glued as a laminate. Beneath the top is a 10" x 3" channel, with plates welded across the end, which are in turn bolted to the horizontal side members of the bench frame. The channel is drilled and studded at the correct pitch for mounting the lathe. steel spacers are set in the wooden top to bring the reference surface level (ie co-planar!) with the top of the wood, the drip tray is then placed on the spacers and the lathe mounting blocks placed next. The lathe can the be set up in the usual way.

A very solid foundation.

Graham

Your reply starts off as plain common sense (Alignment not Level that matters) but then you quote what I would call on old wives tale as stated by Myford (Accurate work CANNOT be expected if the lathe is not level)!!! Not surprising is it that Myford's went down the tube. If they meant 'aligned' why didn't they say so.

I have no doubt that the two and a half pages are useful and informative and if followed carefully allow the lathe to be aligned, I have not seen the document but does it clearly differentiate between the importance of level and aligned?

Using a level that meets Myford's specification it seems possible that a bed 2 feet long could have a 5 thou 'twist' from end to end.

You seem quite disparaging as regards lathes on ships, I am sure there are ships engineers who look after their machines and who make and repair high precision parts. As Martin said a lathe would turn out accurate parts stood on its end.

I am quite happy to accept word 'leveling' as a term to describe alignment in respect of lathe but a spirit level is by no means essential for the purpose, it is only one of several and aids and continuous references to the use of a precision 'level' just add to the confusion (and myth!)

Ian

Ian,

Twist is measure across the bed, the length of the lathe is irrelevant. In your example, to use your figures the twist is 0.0015" since the bed is 6" front to back

A couple of things sping to mind.

as has been pointed out many CNC lathes do pretty good work with the ZX plane any thing but level.. ( just wandered round and found all but 1 are at 45 to horizontal and that "odd one" is a "GANG TOOLING" turretless) also from my limited experience .. limited to HARDINGE HARDCREAT machines.... no leveling is done or required ( HARDINGE machine tool's own book of words ).. apart from not to excess because of coolant or hydralic levels.

And these machines seem ok ..

once had a rep come in selling digital high res "dti" .. clocked one of our older mc .. thought his gizmo bust ...coudn't find any runnout or squint... ( and that on a '91 machine)...

the only mc ever leveled was a MAZAK and that was to get rid of 0.1um on 300 mm ...not bad with out tailstock....

Any way back to "our" machines...My guess is if machine if un clamped the bed will obey Mr Young and bend headstock to tailstock as to level then it is best to keep center of gravity above "feet"..

If you now clamp your lathe so that the feet need to warp the bed ..a subtle warp say... to balance the "sag" of gravity of you lathe bed ...might be of benifit but forcing your lathe and its bed to match some notionally flat bench top would mostly make thi9ngs worse...

as to testing.... HOW DOES IT CUT

Folks,

One of the joys of the English language is the multiplicity of meanings that can be applied to the same word and the subtlety of expression that results from the context. If I may selectively quote form Chambers' dictionary: " level: ...a region with no considerable inequalties.....a condition of equality....". The word level is surely a reasonable one to apply to attaining the condition where the 2 shears of a lathe bed are in the same plane. There is no hint in this that they have to be in the same plane as the surface of the earth - which, as we know, is curved in both the X and Y planes and has to be taken into account when installing large machines.

Using a precision level is just one way of ensuring that the lathe is set up correctly, most appropriately in an industrial context where such things are readily available. Other methods, so eloquently described above, are available to the amateur that may be more lengthy but do not need the purchase of expensive equipment. Myford have, in their usual thorough manner, given us a choice of methods, from which we can choose the one most appropriate to our resources.

So, to answer the OP - the lathe does not have to be level with the ground but the shears do have to be set up so that the lathe turns parallel, a condition usually achieved by ensuring that the shears are not twisted and are level with each other.

Rod

I might promote some wrath here, but having introduced the subject of lathes fitted on ships and submarines I feel more is needed to explain the reference.

I was using the example just to question the concept of 'level' and it's importance in setting lathes up correctly. On dry land that is easy to establish, but on floating platforms it is anything but; hence my observation that 'rigid' was what was really needed. That seems to have been accepted by several others as well.

I think Graham was a bit provocative with his comment. Ship's chief engineers are the custodians of their workshops and I feel sure they would be rather upset to think they would allow such equipment to be abused; the risk exists industrially of course and culprits found doing so would be suitably roasted in either regime.

Brian

I understand Myford tool over Drummond lathes.

What was their procedure for levelling the bed of a Drummond round-bed lathe?

Neil

In Basil Brush's words....

Boom Boom!

Hello Graham'

Thanks for clearing that up, I didn't think it would be intentional. Twist from the hull would be a risk.

Sorry to doubt you

Brian

I certainly didn't intend opening up such a can of worms with my simple question, mind you it has all made very interesting reading even if I don't understand a lot of what has been written.

As for my original question "Would not a normal level be sufficient?", I think the answer to that is a resounding yes and that I should make sure, as far as I am able, to set the lathe up with minimal twist in the bedways - I will do my best.

I have learned a few unexpected things from this topic, not least of which is to remember what I have already read. I refer to Harold Hall's first post with the link to his site. Harold, what you describe on your website is of course in your Lathe book which I have owned for a number of years but forgotten about. You'll be pleased to know that I have started reading it again

I have also finally figured out who Tubal Cain is/was. I have been watching a guy in America (mrpete222 on youtube) who calls himself Tubal Cain but have now realised he is just using it as a pen name as indeed was Tom Walshaw writing for Model Engineer.

I was also pleased to learn about College Engineering Supplies, thank you Graham, a very useful source of materials for the small hobbyist such as myself.

I am collecting the lathe tomorrow so we shall see,

Regards

Brian

The original Tubal Cain was a biblical descendant of Cain. The general interpretation is that he was the first metal-worker but wikipedia gives a few different interpretations. I think in the US he is strongly associated with freemasonry, more so than in the UK.

Neil

**LINK**

A splendid Victorian poem about turning swords into ploughshares

Rod

To expand a little on what Graham quotes from the Myford manual. In the section headed "Checking the Levelling" it starts. A final check---- can be carried out by turning a test piece and then explains how final adjustments are done by raising / lowering the appropriate mounting points.

Logic tells me, that Myford are therefore saying, even if you have used precision levels, or the test bar method, you may still be able to improve on the result.

For me, using a spirit level, or a test bar, are only quick methods of getting very close to the best possible mounting. Without them, the test bar only method will just take a little longer.

Harold

The overriding benefit of verifying the flatness of the bed with a precision level is that if the lathe subsequently turns significantly out of parallel, then that is a good indication there is some kind of fundamental fault in the alignment of the machine.

Using only a test bar may allow a nominally parallel part to be produced, but that may be as a result of introducing an unwanted (and unneeded) twist into the machine, which will almost certainly have detrimental knock-on effects with regard to use of the tailstock and fit between saddle and bed.

Martin.

As you say Martin, if a significant error exists then it will become apparent, even if only having set the lathe making a test piece. You will then be prompted to go looking for the reason.I do wonder though how often such significant errors occur, unless one has purchased a very old machine that shows signs of considerable use.

We should not give the impression that the spirit level is vital as many cannot justify the expense, I know having first hand experience. Having had a lathe laying mostly idle for many years I eventually purchased a milling machine knowing that one would benefit the workshop appreciably.

However, I did not know that the drill chuck would not hold end mills but as I could not justify the expense of a cutter chuck, I decided to make one. Unfortunately, I needed a steady to do that but as I could not justify the expense I decided to make one, and so it went on. A precision level was certainly way out of the question.

Of course, if one had such a level then one would be foolish not to use it.

Incidentally, the cutter chuck is still being used some 25 years later

Harold

Edited By Harold Hall 1 on 23/02/2013 16:52:13

Just to take Gray's point about the Drummond round bed a bit further - and this is only meant to apply to the Drummond round bed - the easy way to avoid twist in the bed is to NOT tighten up the grub screw that hold the bed into the tail end mounting. The bed tube is machined (originally) to 3 inches od. +/- one tenth of a thou, and is a very good fit in both the headstock and the tail end foot, and is held in place at both ends by a short pointed bolt that locates into a dimple in the side of the bed. Secure it at the head end as that is where you want the alignment but leave the screw just finger tight or even a bit looser at the foot - you won't twist the bed then. The tail foot is simply a support, the tail stock and lead screw are supported and guided from the bed only.That's the way I've mounted mine - and the way I intend to mount the other 3!

Keith