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Anchor to the floor or not? (new lathe)

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  • Anchor to the floor or not? (new lathe)

    Grizzly would have me level the base cabinets of the G4003G, shim & anchor them to the floor, then also shim/level the lathe to the cabinet tops.

    I've watched Ox Tool, Abom, etc. on leveling and appreciate their machines have wider bases then mine. And I'm not overly confident about the leveler holes in Grizzly's cabinets
    being nearly directly under the ways, but most web info has very few people actually bolting the machine to the floor.

    I've got an idea for using jacking screws in the leveler holes bearing on steel rounds on top of the concrete floor, then shim under the widest portion of the stands.

    I really don't see the machine actually toppling over but I do tend to err on the side of "damn, that would hurt"...especially after a friend is recovering from having a P&W fall over on his leg!

    As for leveling under the cabinets AND between the lathe and the cabinets...I think someone's playing fast & loose with translations.

    The lathe bolts positively to the cabinet top...why not level it all under the cabinet as one assembly?
    Len

  • #2
    JMO, but I use a carpenter's level on top of the cabinets but under the lathe bed to roughly level the cabinets, then a precision machinist's level on top of the ways to level the lathe and remove any twist from the bed. As you noticed, those fellas have toolroom lathes with wider ways and bases, but even on non-toolroom machines I wouldnt worry about the machine flipping unless youre worried about it being bumped hard by vehicles. Ive seen shapers walk themself around the shop, and lathes hit some pretty bad harmonics but never move.

    Out of curiosity, how did a P&W end up on top of your friend? Was he moving it or.....?
    "I am, and ever will be, a white-socks, pocket-protector, nerdy engineer -- born under the second law of thermodynamics, steeped in the steam tables, in love with free-body diagrams, transformed by Laplace, and propelled by compressible flow."

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    • #3
      While its nice to know the floor is level for your lathe mounting, most lathe makers did not consider this necessary
      and that means in many cases the lathe bases / cabinets are not perfectly parallel floor to lathe feet .
      More important (IMHO) is adding mass to the lathe structure. Certainly mounting the lathe base to a concrete floor will add greatly to lathe performance and also give you the assurance it will not fall over on you . The only time I have ever run into such a "falling over" event, involved the Loma Prieta" earth quake in California back in 1989.
      So attach the cabinet to the floor and level the lathe at its footpads and you should enjoys a good setup and lower vibration
      Rich

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      • #4
        [QUOTE

        Out of curiosity, how did a P&W end up on top of your friend? Was he moving it or.....?[/QUOTE]

        Yes, trying to move it away from the wall.
        Lucky for him the neighbors heard him yelling for help as there was no one else at home!
        Len

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        • #5
          Originally posted by Rich Carlstedt View Post
          While its nice to know the floor is level for your lathe mounting, most lathe makers did not consider this necessary
          and that means in many cases the lathe bases / cabinets are not perfectly parallel floor to lathe feet .
          More important (IMHO) is adding mass to the lathe structure. Certainly mounting the lathe base to a concrete floor will add greatly to lathe performance and also give you the assurance it will not fall over on you . The only time I have ever run into such a "falling over" event, involved the Loma Prieta" earth quake in California back in 1989.
          So attach the cabinet to the floor and level the lathe at its footpads and you should enjoys a good setup and lower vibration
          Rich
          You're makin' a lot of extra work for me there, Rich.
          Len

          Comment


          • #6
            Len
            It sort of what the manufacturer is calling for.

            You mention that the mounting holes are almost directly under the ways and using jacking screws.

            In that case, the lathe would be tippy , and your shimming under the wider part of the base is manditory.
            So I agree with your thoughts, and only suggest anchoring for added stability.

            Rich

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            • #7
              Nearly any machine tool can benefit from being securely fastened to a large mass. It can both stiffen the machine and damp vibration. My home made CNC mill is built on top of an old surface plate that is 24" x 24" with 5" of ribbing and it weighs 205 lbs and sits on three stub legs. The machine is only a minimill but mass makes quite difference. At a place I worked we had 72" Toshiba Blanchard style grinder with a 200 HP motor. I did some troubleshooting and had to read the manual. I asked the operator if it was accurate and stayed accurate. He told me that it varied all over the place and if the fork lift went by it changed the part dimensions. It was sitting on a 6" thick concrete floor. The manual called for a 3 foot thick foundation about 10 feet square, unconnected to the surrounding floor! DUH!

              I think the massive and yet cheap concrete lathe bench someone had here was a very good idea.

              Comment


              • #8
                The idea of bolting the machine to the floor is not really to prevent tipping over, although that is a safety consideration. If you are going to level it, you are going to be trying to get the ways level within a thousandth of an inch or LESS. At these levels of movement, cast iron behaves like rubber. From personal experience I can tell you that moving a machine table or other support structure just an inch or less on a concrete floor WILL raise or lower the points of support (feet) up or down by much larger amounts and destroy any leveling efforts that you may have made.

                It is not really necessary to bolt it TO the floor. It is only necessary to prevent it from moving around on the floor. You can, of course, use anchors that do bolt it to the floor. But in one lathe installation where I did not want to drill any holes in the floor, I used a bracket that fastened the lathe's table to the wall behind it so it could not move around. It was attached to the rear legs just a few inches above the floor to prevent any possibility of the legs flexing. The subsequent leveling held for several years.

                You probably want some levelers on the table legs. On my SB table I have fabricated them from bolts (round the heads), coupling nuts, and U bolts to hold them to the legs.
                Last edited by Paul Alciatore; 10-19-2014, 06:36 PM.
                Paul A.

                Make it fit.
                You can't win and there is a penalty for trying!

                Comment


                • #9
                  A light gauge sheet metal or light sheet steel base will "move" in temperature fluctuations no matter what you - same applies to putting or removing "tools? into or from that very handy cupboard under the lathe.

                  Just do the best you can and adjust your procedures to suit.

                  Comment


                  • #10
                    Well, yes sheet metal is no good here. I am not familiar with the Grizzly "cabinets". My lathe is on a welded steel table made with heavy gauge channel, angle, and 1/8" sheet. The lathe sits on a single large piece of steel channel which is welded to the table top.

                    If the Grizzly "cabinets" are indeed just sheet metal, then I would not worry about leveling. I would bolt the lathe down to them using tight bolts ONLY on it's three highest legs (three point suspension). The other legs would have loose bolts in them, perhaps with rubber or cardboard shims. This would avoid putting any stresses on the lathe bed allow it to take it's own shape which is probably the best you can do under those circumstances. But I have looked at the Grizzly web site and the stand they show looks like a heavy, cast base, not sheet metal.

                    The following assumes that you do have a good, heavy, cast iron, steel or other suitable base.

                    Why level both the base at the floor and the lathe on top of the base? If you want a firm set up, you need to start with the cabinet. If it is not firmly supported by all legs, then it can rock or shift and any leveling of the lathe would be useless. It must be at least solidly mounted. The actual degree of level is not so important at this point but I would want it within about one degree of level to make leveling the lathe easier. And once you have established such a firm seating, it needs to stay put to avoid any changes to it.

                    Now, leveling the lathe ON THAT FIRM BASE is intended to make the ways as parallel to the lathe axis as possible. If there is any twist in the bed, this will not be true and you can be turning tapers instead of cylinders. That will drive you nuts if you are doing precision work. Now, the base must be firm enough to actually allow you to take any twist out of the lathe bed when you level the lathe. If you have not leveled (or at least firmly mounted) the base first, then you will be fighting any flexing in that base. Or if you just bolt the lathe down to the base, thinking that you can then "level" it at the floor, that base may not mate perfectly with the lathe feet. This means that could actually introduce even more twist into the lathe bed and you have two or five times the original problem to try to correct. This is not a good idea.

                    By firmly mounting the base and then leveling the lathe on top of it, you can more easily bring the lathe to the degree of "level" needed for precision work. Hence, the Grizzly instructions.

                    As for temperature fluctuations, hopefully, if the base is constructed from the same materials in like places (like all the legs are CI) then the temperature changes should have minimal effect as all parts would expand or contract by the same amount. The cabinet or table design should be simple in that the various parts should be similar to other like parts. Legs the same material and size, the same for cross pieces and other braces, etc. Any motors or other heat producing devices in the base should be well ventilated to prevent heat build up.

                    Yes, moving tools on or off the lathe or into or out of the storage areas may change the level. I guess ideally the storage areas should be completely independent of the lathe supports. In the real world, I think most people do not worry too much about this if the floor, base, and installation are all solid enough and properly performed.


                    Originally posted by oldtiffie View Post
                    A light gauge sheet metal or light sheet steel base will "move" in temperature fluctuations no matter what you - same applies to putting or removing "tools? into or from that very handy cupboard under the lathe.

                    Just do the best you can and adjust your procedures to suit.
                    Paul A.

                    Make it fit.
                    You can't win and there is a penalty for trying!

                    Comment


                    • #11
                      Its odd but there is rarely if any discussion on a lathe bed having bent horizontally - there is not much if anything you can do - just put up with and work around it as best you can.

                      Most discussion seems to presume that the lathe is (as?) "new" - ie not worn - particularly on the bed and under the carriage near the head-stock. In many instances the lathes under consideration are worn there - an at the cross and top slides as well.

                      Comment


                      • #12
                        Originally posted by oldtiffie View Post
                        Most discussion seems to presume that the lathe is (as?) "new" - ie not worn - particularly on the bed and under the carriage near the head-stock. In many instances the lathes under consideration are worn there - an at the cross and top slides as well.
                        Well, what would you do about that sort of bed wear?

                        You have, short of re-grind etc, the option to shim and fiddle to get the lathe to have compensating errors in the "leveling", or deal with it. Usually that sort of wear is nearly irrelevant, simply because the errors show up only on the smallest diameter parts, and the smallest diameter parts are generally not long enough to cause it to be an issue.

                        You yourself have shown calculations of the diameter errors arising from the wear, and have correctly shown them to be quite tiny for most typical part diameters.
                        1601

                        Keep eye on ball.
                        Hashim Khan

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                        • #13
                          One of the best machinists Ive ever known once told me that a decent machinist needs a decent machine to make parts, while a great machinist can make decent parts on anything. The same guy became very wealthy building custom modern manufacturing machinery in a shop full of old flatbelt machines.
                          "I am, and ever will be, a white-socks, pocket-protector, nerdy engineer -- born under the second law of thermodynamics, steeped in the steam tables, in love with free-body diagrams, transformed by Laplace, and propelled by compressible flow."

                          Comment


                          • #14
                            Originally posted by Paul Alciatore View Post
                            Well, yes sheet metal is no good here. I am not familiar with the Grizzly "cabinets". My lathe is on a welded steel table made with heavy gauge channel, angle, and 1/8" sheet. The lathe sits on a single large piece of steel channel which is welded to the table top...

                            .

                            The G4003G was one of the few Grizzly lathes with cast iron cabinets, but now it is described as "Heavy duty steel stand" - though the images look like the old CI stand:

                            http://www.grizzly.com/catalog/2014/Main/568

                            Comment


                            • #15
                              I don't have any of my machines bolted down. So far I have not had an issue with them. My Clausing/Colchester would not run above 1000 RPM without a bit of shake, but that was the heavy unbalanced chuck it had on it. I now have a smaller chuck but have not needed the higher R's to see if is still a chancy area to work in.
                              Bolted, they are not as easily moved around if one needs the space or sells or acquires another machine. Not to mention the holes drilled into the floor. And with my shop always in jeopardy of flooding, I don't need another water access place. I'm sure the holes wouldn't work out for me as drains, either.
                              Lathes may need tied down if one does a lot of faceplate or four jaw work with unbalanced work. But mostly such work is not spun in higher R's. Lathes are subject to tipping while moving them due to their usually being top heavy with small foot print area. My model 100 Clausing is a bit iffy but mostly due to the home made bolted together bench. The bench is not as heavy as it should be. I hardly use that machine due to the bench and the carriage wheel gear shaft needs bushed to OEM size as the wear allows the feed gear to wobble and finish suffers on the work.
                              Krutch


                              Mentally confused and prone to wandering!

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