View Full Version : Leveling a lathe
02-03-2005, 12:23 PM
Or any other machine for that matter. I need to level my lathe. It is on a concrete floor. Four legs. What is the best material to use for shims under the legs? Pieces of steel plate? There are holes in the bottom of the legs. Would a steel plate with a threaded rod a nut type of deal work best?
02-03-2005, 02:23 PM
Andyz, Like anything there are several acceptable methods. Steel shims (highly reccomend against plastic) will work but are the biggest pain in the rear. Allthread double nutted would work, but due to the small contact area may change over time as it might tend to dig in the concrete. The next better method would be to use LEVELING FEET - (McMaster-Carr amoung a bunch others sell these) these are basically set screws with swivel pads on them to allow for increased floor contact - fairly cheap. For BIGGER equipment they sell leveling block - these are rectangular shaped pads that are two pieces that assemble together with an internal ramp. As you tighten the bolt it slides one half UP the ramp allowing adjustment that way. These are PRICEY and unless your lateh is BIG I wouldn't bother.
Some lathes are designed to be anchored to the floor and the anchor pads are threaded - you adjust in place. Others (mostly cabinet style) can often be bolted direct and leveled at the TOP (between the BED and the Cabinet - my Rockwell is like that.
I see alot of the SFD machines using a largish levelign foot with rubber (urethane?) - in theory this woudl be ok - but personally I would check ot every so often to make sure it is STILL in spec - which is probably a good idea with any method as floors themselves sometimes move too.
Jacin in Ohio
Renee n Jerry Conrad
02-03-2005, 05:30 PM
Jacin's allthread idea might be applied to a bolt, turned true on the head to get more footprint. A large flat washer could be welded on the bolt head to increase the footprint further. A finish cut after welding would be in order. To chuck the bolt screw two nuts on it, one at each end of the thread, chuck the nuts in a 3-jaw, and the bolt will pull up to the end of the thread, or against the chuck. Accurate enough for this work, and it doesn't ding up the threads.
Hope this helps,
02-04-2005, 06:40 AM
You may find it worth your time to get ahold of a precision level. These levels have graduations that measure 0.0005" per 10 -12" depending on the type. These are very helpful in leveling larger machines. Smaller stiff framed machines tend to be a bit more forgiving than a larger machine. A larger machine may take several sessions over a period of days to get it right, it takes time for the frame to settle. It really boils down to how much you want to fuss with it. I have never met a person that was sorry they did a thorough job setting up a machine.
02-05-2005, 04:26 PM
Joe, what in the hell did you have to level that weighs 75tons? :shock:
02-05-2005, 05:41 PM
75tons? I can see that. I was at an auction in Philadelphia last week and saw some machine tools that blew my mind. They had 3 horizontal boring mills that were 12 feet tall and had a table that you could park a city bus on. I saw lathes that were 20 and 30 feet long.
I was talking to the riggers and apparently one of the bidders was interested in moving one to China and another was going to Central America.
The boring mills sold for $45,000, $5,000 and $800. I'm guessing the last one is for scrap. Same story with the big lathes $22,000, $9,000 and $500. So if you were in the market for a 20" by 144" lathe, you missed a steal :wink:
02-06-2005, 07:05 AM
So long as we're on the subject. We installed a machine for work at a site - not so big - but three pieces that were 2,500 4,000 and 1000 pounds respectively. We aligned them and blessed them for service. A week later the customer complained that the resolution was crap and they were VERY dissatisfied with the equipment. Our service group sprung into action to readjust the alignment and low and behold it was PERFECT. They ran some verification tests and still everything was perfect. They drug the customer in and they were satisfied. A week later - REPEAT of the situation - resolution was crap and they were NOT happy. We did this back and forth for a couple of weeks until the SERVICE group called in for reinforcements. Everyone was still perplexed - every diagonostic test proved it was right on - every aligment tool verified the fact. THEN one day mid stream the alignment went to heck right in the middle of a test. :shock: It took them a while to figure it out but what was happening was that in the room next door they had a LARGE mobile piece of equipment - it was in place 90% of the time as it was when we installed OUR equipment, BUT when they moved it the floor position changed and our alignment was affected.
Another method we use is to "pour the floor" in our case we do this several ways, but in short we use a leveling compound called Micorox Grout- basically a two part epoxy. You can prelevel sections of floor this way or level your equipment and "pour in place". We use the equivalent of shelf paper or even petroleum jelly as release agents. Our equipment often runs several feet on some sort of track - the support structures (floors) typically flex and we've found out it is much more consistent to place our loads (equipment) in place even if we are not pouring in place - meaning we LOAD our floors to simulate the deflection caused by our equipment and then pour a level base. Adjustments later are only minor this way and we can control floor loading much better.
I keep thinking I will need to pour footings for my Pullmax not so much for the weight, but the vibration- so far so good.
In any event checking level at intervals to allow for settling is a good idea. IMHO
Jacin in Ohio
02-06-2005, 12:00 PM
My uncle was telling me about a mill the had at a concrete pump truck company he worked for. it was around 75 feet long and 10 feet wide and was used for doing some machining on the main booms of the trucks.
03-25-2005, 02:45 PM
It's best not to span any expansion joints or cracks in the concrete floor. The two pieces of concrete will move independantly of one another and play havok with your leveling.
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