Leveling Mill

chevydyl said:
I forgot to throw in the twist (which happens to be more what I meant not just gravity) that could be applied to a machine not level, but think of the big ol unsupported mill table hanging off all the way to one side, now throw some twist into the machine because it's not leveled, run it like that for awhile and it will cause uneven premature wear. Let's agree that in the home shop you may never see it, but a machine used daily surely will show signs.
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I first asked if it were a small stand alone mill, such a machine will not be twisted by it's own weight like a longish lathe might be.
 
True, and if it was never scraped then it surely don't matter.
But take into account the setup thing, that's reason enough to level a mill
 
chevydyl said:
True, and if it was never scraped then it surely don't matter.
But take into account the setup thing, that's reason enough to level a mill
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Has no relationship with scraped ways, a simple bridgeport knee mill will easily handle a 400+ LB part on the table, if they were easily worn by their own weight when out of level I would suggest never putting so much as a vice let alone a vice and a part on it, think of the possible wear that would cause (-:
 
Wreck™Wreck said:
I first asked if it were a small stand alone mill, such a machine will not be twisted by it's own weight like a longish lathe might be.
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Don't underestimate how easy it is to flex cast iron. I used to have an old US machine tool vertical mill (predecessor to the millrite), and it flexed when not leveled. Not to mention it dampened vibrations better when leveled.
 
Very true dan, good point.
Put an indicator in your bridgy spindle, on the table vise or whatever, push down on the back of the ram with only slight pressure, I was like wow, pretty much a limp noodle, a hard breath could just about make the needle move. We all have opinions, my opinion is that it is necessary to level all and any machine that has slide ways to preserve the accuracy and condition.
Cast iron moves extremely easy, why do you think they setup the castings on a 3 point when checking dimensions for scraping? If on 4 points it can and will sag under its own weight, deflection is quite amazing, very interesting, consider the same when the machine was built a certain way, then you go throwing a tweak into it..... do what you want with your own machines, but my machines are level, and checked on a monthly basis to ensure the foundation hasn't crept. My lathe has had to be releveled, on account of the concrete base I poured especially for the lathe to sit on, I don't know exactly why but it moved.
Fun fact, say you scrape your machine in my garage at 50 degrees, and she's perfect. Then it gets moved into a shop at 75 degrees, it will wear differently than it would if kept in the colder climate where it was dialed in. And yes I'm aware that in the home shop you may never notice in your lifetime but the daily use for 10 yrs will have an effect.

This is a good discussion
 
The last thing I would do is put my mill on a slab of steel plate. In the 40 something years, all my mills have always been supported on four square blocks of wood. Either 1 x 4 stock or 2 x 6 or 8 stock. Then on top of that if needed various shims to get the table reasonably level. Again, don't have to be perfect as to leveling a lathe. Wood will keep a mill from moving around if from rock and roll country or heavy vibration from cutting tools being used. And please don't bolt your mill down to the concrete! Unless it is one of top heavy one's that could tip over, then bolt it down.
 
I put it on the plate to even out the load on the concrete floor, instead of just four corners, not my floor
Once level I'll weld stops to plate so base stays there .
Trying to come up with suitable shim material, think I'll try spray paint can metal for the thin stuff .
Don't want to spend $70.00 for ss shim stock.
As mentioned I will be useing a level for some setups.
But anyhow Thanks for the input
 
The cabinet under my mill/drill has 1/2" X 13 TPI bolt holes for leveling, ,it is currently sitting on 4 bolts that rest on 4" X 4" plates. I have used a level in setting up some projects, checked the table and adjusted to it. May have to move the mill so will recheck for level again.
 
I'm thinking being a little low on the right side ,oil from feed screw is getting into my servo powerfeed
I started another thread on servo powerfeed w oil in it , may be related to mill not level.
Thoughts ?
 
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