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Thread: Bridgeport Mill Leveling

  1. #1
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    Jun 2005
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    Default Bridgeport Mill Leveling

    I have a Series 1 Bridgeport mill I have been working on for some time. I am about to start enough of the re-assembly process that I really want to have it in place and as level as possible before I make it any heavier.

    My concrete floor is imperfect as they typically are. Its not rough, but is not perfectly flat either....and likely the bottom of the mill base casting is not either. Up till now, I have used some steel shimming to level it, but with the four corners as contact points, you end up chasing it in circles and it is inexact at best. The real goal is to make it stable, but I have a precision level and I would like to be able to level it both directions.

    There are 4 holes in the base and I have been thinking of ways to try to make some sort of levellers while I can still get under the thing to set them in place. The design does not make this easy as you really need to be adjusting a nut on the back side from the holes or a bolt protruding through the top side, and I was wondering if any of you knew of or could provide a picture of a commercial solution to this. I had been thinking of ways to accomplish this for some time and then was inspired when I saw the picture of something like this in this picture from a recent thread. Anyone done something like this and have a picture or diagram of just how they made the "feet" and made them adjustable from the top side?

    Thanks in advance for any help you can offer!
    Paul
    Paul Carpenter
    Mapleton, IL

  2. #2
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    Aug 2002
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    Menlo Park, CA
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    Default

    Does your Bridgeport not have the threaded holes in the base?

    Mine does; I got it (well) used and there were 3/4" (?) leveling screws in each of the holes. I just used a precision level and tweaked the screws until it was level and stable. The screws have no base, just a turned down section at the end so you can get them out again after jamming them against the floor.

    - Bart
    Bart Smaalders
    http://smaalders.net/barts

  3. #3
    Join Date
    Mar 2005
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    408

    Default Mill levelling....

    Search this, some has been said before. Iirc, the concensus was that mills don't really care if they are precisely level, unlike long bed lathes....A vertical mill is a pretty stiff structure.
    The levelling would only be for your convenience, or to use as a reference when setting up. Probably could use adjustable levelling/ isolation pads made from hockey pucks, steel & ready-rod.
    I should talk, I have my Rockwell mill on wheels....(with levelling feet.)
    Rick

  4. #4
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    Dec 2006
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    Marshalltown, IA
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    156

    Default

    It's nice to be level just so things don't roll off the table. Tap the 4 holes if they aren't already. Use some threaded rod to make up 4 adjusting screws. Mill 4 flats on the top and radius the bottom. Make 4 aluminum feet out of 3-4" round. Flat on the bottom, 1/4" thick at the outside to clear the casting, step up to at least 1/2" at the center. Use a ball mill to form a 'socket' in the center of each foot for the adjusting rod, matching the radius. Place some heavy rubber underneath the aluminum feet. Make sure you put a dab of grease in each socket. Works great.

    Marc -

  5. #5
    Join Date
    Oct 2006
    Location
    Ivins, Ut
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    Default

    We often overdo a project just to make it look good and us feel good. (There's sometimes a useability advantage and learning bonus too, of course). If all you're worried about is the machine, I'd use a carpenter's level and stick with the shims. If you use good sized shim material, say 4" square, there is absolutely no problem with only the four corners of the base having contact with the floor. In reality I suspect you'll find more contact than that for most of it. A precision level for a mill is a whole lot of extra effort for absolutely no return. I do, however, bolt my mill to the floor because it helps dampen vibration and I occasionally need to climb on it!
    Gordon
    Last edited by chipmaker4130; 02-08-2007 at 01:13 PM.

  6. #6
    Join Date
    May 2005
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    UK
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    Default

    Quote Originally Posted by Marc M
    It's nice to be level just so things don't roll off the table.
    Marc -
    I was putting keyways in the ends of 6 feet of 2" dia 316 shafting this afternoon. My shop 'reorganisation' isn't quite finished yet, & the mill is on some bits of bar to make it easier to shunt around. As I wound the table along for setting up, the whole mill went past it's point of balance on the bars & would lurch to one side, then back again when I wound the table back. No danger, but a bit alarming to anyone who might have been watching. Lucky they weren't

    Tim

  7. #7
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    I am feeling a little stupid...I didn't think of just tapping the existing holes (they are not currently threaded). They measure about 5/8. I kept thinking in terms of some sort of nut on the backside....which you cannot then reach with the mill in place. I kept thinking this way because I didn't think there would be enough strength in the existing holes for support, but it sounds like that is not the case. I was thinking nut and washer on the back side.

    Level would be my preference.....but just keeping it from rocking due to an uneven floor is the first priority. I realize it is not a flex issue as with a lathe, but would prefer that stuff doesn't roll off and that the whole mill cannot rock. As I mentioned, just stuffing shims makes it awfully easy to end up chasing the one corner that doesn't touch from one corner to the next. This is exascerbated by the fact that each corner is not a point contact, but about three inches on either side of the center of the corner.

    I will probably go ahead and clean up the holes with a proper size drill and tap them and make a couple of plates with dimples for easier use. The preference would be to leave it on its corners where I can and use the levelling bolts only to lift the "low side".

    thanks
    Paul
    Paul Carpenter
    Mapleton, IL

  8. #8
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    Jul 2005
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    N W La.
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    I just finished my leveling new "Bridgeport clone" from ENCO -- and it IS very similar -- but the seemingly 3/4" holes were to sloppy to take that thread, so had to go out to 7/8", and the clone was the same dia through the full 5" so I did a partial thread and made a pin out of the bottom on the all-thread. The stuff was pretty tough!!. In case that didnt make sense, heres a pix........

    If everything seems to be going well, you have obviously overlooked something........

  9. #9
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    I had hardwood packings, about 6" sq x 1" thick, plus steel shims under my mill before moving it & will probably reproduce that arrangement. It provides just a tiny bit of flexibility & cushioning, so that the packing doesn't have to be exact to the last thou to stop it rocking.

    Tim

  10. #10
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    Mar 2005
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    Toronto
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    its nice to have the mill level, just feels right. my garage floor slopes over an inch or more over the length of the casting - the look of it made me walk crooked until i fixed it.. there are advantages if you are using coolant, and i can remember at least once when i used a level on the work to help with a tricky set up.

    I ended up putting my XLO on three feet. The feet are round pieces of metal, say 2" dia, length to suit, and cut in wedge shape - one the faces of the cylinder is an a small angle. levelling is a piece of cake: set a prybar up and and slide the wedge under the machine, with one foot on the prybar, and a stick or broom handle to move the wedge around, plunk the machinist level on the table and have at it. obviously never ever put any body part under machine while lifted

    are 3 feet less stable than 4? probably, but the mill is close to 3000lb's and solid and in ten years haven't done anything that would even remotely would come close to having it topple over.

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