View Full Version : leveling heavy machinery

02-01-2004, 09:28 AM
by heavy i mean 3000-4000 pound range (not 1 million pounds like the stuff in Carl's pics). so i was trying to level some of my latest purchases (that big shaper and mill) and was putting metal shims under the corners to level them. the floor of my garage, i mean shop, is concrete. then i read in an old Brown & Sharpe manual that they say to use wood shims to level and then bolt the machine down. well, first, i'm not bolting anything anywhere, as i don't plan on taking 1/2" deep cuts in single passes.
as i read this, i got to thinking that i've been in several shops (and seen many photos) with wood floors. so using wood to level the machines seems like it would work.

so what is the general consensus? can i use wood shims to level machines on a concrete floor? and do i really need to bolt this stuff down? i'd use metal, but let's face it, i can whip up a wooden shim of any thickness in 20 seconds. i don't have this luxury with metal (not yet anyway).

andy b.

02-01-2004, 09:37 AM
It works. you might want to check level every once in awhile to make sure nothing has moved. Wood expands with moisture so its a good idea to check. After a number of years the shims wind up impregnated with oil and tend to stabilize. BTW we used cedar shakes for shims along with a plastic padding material.

02-01-2004, 01:02 PM
Relatively thin neoprene sheeting say 1/8" to 1/4" thick on metal such as lead or aluminum if you have it works better than wood. The humidity sensitivity is something to avoid and the rubber/metal combination damps vibration and yields under the weight of the machine to take up looseness just as well as wood but then is more stable. Rubber/metal machine pads are for sale by Grainger, Enco, MSC etc. but you can make something up with stuff from Home Depot and the junk yard.

02-01-2004, 07:12 PM
When you get down to it you still have to check level frequently regardless of what you use,even those expensive leveling jacks have to be checked often.

I have seen the use of grout under machine bases,you level it up once and pour a sand and portland slurry under the machine base when it hardens its supposed to stay put,but I have my doubts,its also a PITA if you decide to move something later.

02-01-2004, 07:20 PM
I used wood for years (plywood) and then one day I came accross plastic. I've been using it every since. A good trick is a thin sheet of plastic (1/4") on the concrete, wood in the middle and another 1/4" of plastic on top. Only about once in the last five years have I had to make any adjustments to a machine I set up this way. The plastic I am using is the "Lexan" variety. Very tough. I like to keep about 2" under my machines to fasilitate cleaning with a scraper.

02-01-2004, 08:31 PM

It would be better to shim with steel and Hilti that baby to the floor. Then it won't move on you and you will be surprised how often you will want to take those "big" cuts when you have a machine that has the balls to do it. Never do a job half-assed unless forced to by circumstance beyond your control. http://bbs.homeshopmachinist.net//biggrin.gif

[This message has been edited by Thrud (edited 02-01-2004).]

John Garner
02-01-2004, 09:09 PM
andy_b --

Once upon a time in the late 1960's I saw an experienced shaper operator, who must have suffered a severe episode of "brane faid", start a 16 inch Cincinnati shaper set to a maxium stroke length at maximum speed combination. The clutch screamed and the ram flew forward, pretty much followed by the shaper body. It danced around for a few moments before more-or-less simultaneously unplugging itself from the electrical supply and disassembling itself.

The commotion, arcs-and-sparks, and flying pieces of concrete and iron were, in the vernacular of the day, "mind bending", but by the grace of God there were no human casualties.

Based on that experience, I'd say it's a real good idea to bolt down a shaper really well.


Paul Alciatore
02-01-2004, 10:46 PM
I'll go a bit further on the bolt down thing. Some few years ago I was trying to set up a radial arm saw (yea wood working). It was in a confined space and I needed to reach both sides and the back to make the adjustments so I moved it around and rotated it a bit. I tried and tried for about two days before I realised that by moving it around on the apparently flat concrete floor I was actually causing the frame to flex and all the adjustments to change. I then bolted it down and laveled it and it set up 100% the first try. I sure wish they had talked about that in the instructions. As I recall, a 1" movement in any direction destroyed the 90* setting of the arm by about 1/16".

I suspect this is why radial arm saws have such a bad rep with cabinetmakers.

I firmly believe that any metal cutting machine should be bolted in place on a good concrete slab and carefully leveled before being set up and used.

Paul A.

02-02-2004, 12:15 AM
this board is a neverending source for projects for me.

so the base on the big G&E shaper is a hollow oil resevoir and is about 5" thick. i guess somewhere under all the grease are mounting holes. do i just drill the holes in the concrete through the holes in the base, or do i have to move this monstrousity yet again?

nevermind, i'm sure the answer is that i have to mark the holes and then move it and drill.

oh well, it looks like i'll be moving some cast iron. thank goodness this will only be happening once.

i think i'll go with plastic for shims. thanks for that tip!!!

andy b.

Forrest Addy
02-02-2004, 03:04 AM
Stiff rigid machine tools like knee mills and shapers whose main casting is fully boxed and internally stiffened really don't need leveling.

Leveling it a means of ensuring the alignment of machine tools having long, inevitably flexible structural components - a lathe bed is the first example that comes to mind. Runways for floor mills and beds for planers are others. They are meticulously leveled at the factory and all subsequent parts are fitted, leveled, plumbed, and squared to the level references. When the machine is installed at the customenr's shop the bed is leveled on its foundation. Merely erecting the machine on its level bed results in the restoration of the machine to factory accuracy where only small amounts of final adjustment to bring it into better than specs.

Stiff machine tools like knee mills and shapers sag very little because of gravity. You can get as accurate performance from such rigidly constructed machine tools whether the machine wasleft on a pallet dropped on a cinder foundry floor or installed on a thick concrete foundation.

That said, accurate leveling of shapers and mills can be a convenience to the operator. If the table is level then setting up the face of an awkward part parallel to it requires only a precision level and not an hour or two of painstaking dial indicating.

02-02-2004, 05:31 AM
In 25 years of working in mold shops and having one of my own for seven years the only thing I level my machines with are either the mounting pads that come with the machines or in the case of bridgeports and such I use cedar shake shingles not so much for the leveling but for vibration and sound they will work far superior to steel shims
every time and if you are really worried about humidity and precision you need a constant temp anyway and then expansion on the wood is not a problem if it ever was to start with (plastic might work just as well though). The company I work for now has all of there milling machines and such leveled with them. CNC's usually have there own mounts from the factory so that is not a problem, shapers need to be bolted down but most mills need not be except in rare instances or specialty machines with lots of reciprocating weight. This is my opinion and experience.

02-02-2004, 06:40 AM
........I have no experience in leveling heavy machinery, and the only machine I've paid any attention to leveling was my recently aquired Logan/Powermatic 11" lathe. I called around, and checked around about this, as I did not want to have to drill holes in my concrete garage floor.

I would have if I found it to be necessary. I used Royal machinery mounts each rated for well over 25% of the unit's total weight, and the lathe had 6 mount positions so I got 6 @ $30 each.

I know some of the manufacturer's liturature may be hipe, but it says they meet OSHA and other agencies' requirements for "Non movement" and safety. That satisfied me that they won't move or walk. Time will eventually tell.


02-02-2004, 10:41 AM
I agree with Forrest on the subject of bolting down machines. It is a necessity with long machines like lathes and really big milling machines but it has to be done very carefully in those cases and with $million long bed milling machines the manufacturer is usually the one doing the set up and acceptance testing. It is very possible to introduce a significant error into the geometry of a machine such as a jig grinder by bolting it down to the average good "flat", "stable" concrete floor. That is not recommended by most manufacturers. Super precision machines such as step and repeat cameras used in semiconductor lithography are placed on heavy (2000-3000 lb. ) steel plate weldments supported by air vibration isolators. This approach is used on some super precision machine tools as well.

metal mite
02-02-2004, 12:52 PM
I agree with Forrest.
I put plywood squares under the corners of mine and shim to eliminate any rock.
The shaper and the concrete will bite into the wood and it shouldn't walk if used at moderate speeds.

Alistair Hosie
02-03-2004, 01:29 AM
I saw a great idea in a woodworking book I have, where a guy took a radial arm saw and positioned it as best he could on a bench. He then put two positions along the arm and two fixings either side of the saw with a wire cable/rope between them fixed to both the wall and the arm with a small turnbuckle in between. When all was set up you simply turn the turnbuckles to get absolute accuracy.
It does not affect the working of the saw as the arm is not affected on the inside only the ouside is drilled and threaded for the bolts.
It holds the arm rock steady at 90 degrees to the cut and the arm cannot flex at all.Alistair