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    Default Troubles With Wood Floored Shop

    Here is my lathe, sitting on the 1" thick, 22" wide, 76" long plate. It is on six, 1250 pound capacity vibration mounts. You can see the two 199 levels on blocks on the flat ways. Took a while to get level, then I left it overnight, and have been adjusting it for the past week or so. I figured it would take some time to settle down, and it has. But...when I stand in front of the damned thing, I can watch the bubbles move 2 to 3 hashmarks on the levels. My floor isn't as stable as I thought. Or it might be those rubber mounts.

    I am going to take it off the rubber mounts and put it down on the solid metal levelers to see what happens. I am also going to lay down a sheet of 1 1/2" flooring in front of the lathe to see if spreading my weight helps. I used my studfinder, I do have floor joists on 14" centers.

    Any thoughts appreciated.

    lathe-placed.jpg

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    Quote Originally Posted by Nitromahn View Post
    Here is my lathe, sitting on the 1" thick, 22" wide, 76" long plate. It is on six, 1250 pound capacity vibration mounts. You can see the two 199 levels on blocks on the flat ways. Took a while to get level, then I left it overnight, and have been adjusting it for the past week or so. I figured it would take some time to settle down, and it has. But...when I stand in front of the damned thing, I can watch the bubbles move 2 to 3 hashmarks on the levels. My floor isn't as stable as I thought. Or it might be those rubber mounts.

    I am going to take it off the rubber mounts and put it down on the solid metal levelers to see what happens. I am also going to lay down a sheet of 1 1/2" flooring in front of the lathe to see if spreading my weight helps. I used my studfinder, I do have floor joists on 14" centers.

    Any thoughts appreciated.

    lathe-placed.jpg
    What COUNTRY are you in as use 14" centers for joists? 16" is standard.

    Your body mass was not ON the lathe, so the elastomeric mounts are not at fault.

    The floor moved under YOU, a portion of that movement reflected into the floor, then plate, then mounts, under the lathe, then base & bed UPWARD to the bed and the levels.

    Do you control the space UNDER that floor and its joists at all as to looking into some reinforcing trickery? And if so, is it clear space, or already home to an HVAC system, water heater, bathroom, or such?

    Where I'd be going with this is that I could perhaps build-in a store-room / walk-in closet under that corner that was really a section of bridge, and about as strong as you need it to be.

    ELSE move the lathe to a place you can do that. ELSE move it to where you need not do that, but have or can add a solid slab over compacted Earth & gravels.

    if no joy?

    Just swap the lathe for a decent industrial sewing machine and take up sail-making instead of metal mangling.

    TANSTAAFL

    End of problem.

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    I'd be inclined to first remove the rubber mounts and stiffen the joists below; perhaps by doubling them and adding bridging.

    Just guessing from the lathe and its location that you're not hoping to chase tenths? If so, stiffening the floor might give you most of the accuracy the lathe is capable of providing?

    It's also entirely possible that the weight of the steel plate isn't helping you. Some residential construction was designed for as little as 30# per square foot live load - and that with deflection. Your 1" thick steel plate already exceeds that 30#/sq. ft. load, with the lathe weight (and your own weight) even more. So you might try ditching the plate and locating the solid levelers under the headstock area directly over a doubled joist, secured with bridging all the way across.

    Really hard to know precisely how to best stiffen this floor without knowing its construction and the options open to you.

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    Friend with wood floor shop had same problem, he solved it by cutting hole in floor, framing it in, then pouring full of concrete. Might not be an option for you

    Last time I saw his shop we had just moved in a 4000lb lathe, it was sketchy, getting close to lathe you could feel floor sag. My suggestion at that time was frame around exterior of building, cut 4" holes throughout floor, and start pumping concrete.

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    Will that lathe twist?doesn’t look to be too long from the photo.

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    Put down the levels and step away from the lathe. You are way overdoing the whole level thing. Not to pick on your lathe, but a carpenter's level is close enough.

    Work on making parts instead of fondling your tools.

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    Quote Originally Posted by dalmatiangirl61 View Post
    Friend with wood floor shop had same problem, he solved it by cutting hole in floor, framing it in, then pouring full of concrete. Might not be an option for you

    Last time I saw his shop we had just moved in a 4000lb lathe, it was sketchy, getting close to lathe you could feel floor sag. My suggestion at that time was frame around exterior of building, cut 4" holes throughout floor, and start pumping concrete.
    It need not be all that hard. Now - if in RENTED space, not owned, yah...

    Example IF there is a full basement under, 8-foot+ slab to overhead, and clear space not already allocated.

    4" x 8" nominal, beam each side of a 6' x 6' rectangle, on columns. Cross joists at right angle to the originals, fit to load taken up / leveled with wedge-shims. Spaced according to load, the 6' span joists need not be all that deep. Now you have an area with only 7-foot or so overhead.

    BFD.

    Typical 5/8" plywood flooring simply DOUBLED can support average passenger cars for an automobile showroom floor.

    CAVEAT: Yes, done this. No, am not an RPE.

    Get proper advice and follow that advice for your actual, not "hint at" situation.

    It is cheaper and easier than building a "panic room", for example.

    Which it could become.

    Or a preserves and food closet, (as one of our ones became), or.... lot's of things more useful than a solid mass of ignorant 'crete.

    It can even be removable and portable to the next challenge, just as has to be done all the time for lots of construction or rigging projects.



    And "Oh BTW?"

    WTF WAS going through a tiny little MIND NOT ....to put that lathe there to begin with without doing some basic structural checking and getting advice FIRST?

    Had an Uncle by marriage that klever-klewless onct. Went-over from dairying to raising chick'ns commercially.

    Got rolling good, built him a second-story onto a chickn' house to double his capacity.

    Used him 2 x 4 joists where 2 X 12 shudda been to keep the cost down. Figured chickn's weren't very heavy, after all.

    3/8" plywood floor over them 2 X 4's sagged when he walked through to distribute feed, but no big deal, old cow-patty-hopper was sure-footed enough to not lose his balance.

    Got him a surprise one day when my Aunt came in to feed from one end, he came in from the other end, and three THOUSAND chikn's took flight to go for the feed.

    And then all three thousand of those "not very heavy" cluckers LANDED at near-as dammit the same time!

    Well.. nobody died as didn't have feathered wings already.

    And there was chick'n shit and nitrates enough on and in the plywood the wreckage burnt up right nicely as well.

    You'd have to know French Creek, West Virginia..."back in the day".

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    Quote Originally Posted by gbent View Post
    Put down the levels and step away from the lathe. You are way overdoing the whole level thing. Not to pick on your lathe, but a carpenter's level is close enough.

    Work on making parts instead of fondling your tools.
    Nah, he wants the levels to check twist of the bed, a fine use for 199's. Gross level of the machine, I agree - normal levels are OK.

    On that plate - presumably it's steel? For the weight, it's shape is an inefficient stiffener, so unless the point loading of the leveling feet (get rid of the rubber bits) risks punching through the flooring I'd skip the plate.

    If you're in a situation where there's a basement below the lathe, you might even (carefully!) mount that plate to the underside of the floor, then use a pair (or three) of lolly columns to support the lathe by resting on the floor of the basement, pressing against the steel plate, up through the joists, then to the lathe.

    That should be pretty stable, presuming the joists don't see a lot of swelling/shrinking due to changes of humidity. If there's swelling, then using four columns supporting spreader plates against the underside of the flooring directly is about as good as you're going to get.

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    Quote Originally Posted by Nitromahn View Post
    . . .the bubbles move 2 to 3 hashmarks on the levels. . .
    If the bubbles move 'in unison', or nearly so, it won't matter anyway. The bed will still be flat. If walking back and forth in the normal work area causes differential movement in the indications, it could potentially be significant.

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    Quote Originally Posted by Gordon Heaton View Post
    If the bubbles move 'in unison', or nearly so, it won't matter anyway. The bed will still be flat. If walking back and forth in the normal work area causes differential movement in the indications, it could potentially be significant.
    Bugger drops 8 feet vertically unexpectedly, be OK so long as it stays level whilst "airborne". But they don't. Residences ain't built like the World Trade Center coming down straight as a pile-driver. Failed floor nearly always tilts.

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    Okay guys, I get the point. Nothing I can do about the place it's in, but I'll go the cheap route before I spend too much money. In other words, gluing in a few more sheets of flooring should stiffen it. I need to give this a few days to cogitate on it.

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    Quote Originally Posted by Nitromahn View Post
    Okay guys, I get the point. Nothing I can do about the place it's in, but I'll go the cheap route before I spend too much money. In other words, gluing in a few more sheets of flooring should stiffen it. I need to give this a few days to cogitate on it.
    Thicker flooring also needs cross-bracing of the joists UNDER if dynamic load is to be spread, let alone static load.

    Your better approach is to copy a "bandstand" for Memorial day or such.

    Build a stiff step-up stage atop the existing structure if you cannot do what you need to do UNDER it.

    Downside it that adds mass you already have a problem with.

    Catch 22

    That rules it out on safety grounds.

    Can't get a good situation from a bad situation.

    Movement in residential or office or general-purpose industrial floors is expected, allowed, and designed-in to be safe-enough within limits that a machine-tool may not EVER be happy with, even when strong and safe enough to not fail.

    Bridges move, too. So do airport runways, highways, and adjacent sidewalks.

    Stand on a corner, London, and FEEL a Leyland Titan double-decker pass by.
    Sections of Park Avenue, Manhattan, or several places in many other major cities can make a body uneasy from their movement. There may be cuts for railway trains under that "solid looking" pavement.

    Machine tools need enhanced immobility as much as strength is all. A "machine hall" is purpose-built to deal with that, best it can. Even that is never "perfect", just "good enough" that other s**t matters more, whilst the outfit can go make chips and earn their crust... and a sheckel or three toward the cost of all that reinforced 'crete, too. Hopefully.

    TANSTAAFL

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    Quote Originally Posted by thermite View Post
    Bugger drops 8 feet vertically unexpectedly, be OK so long as it stays level whilst "airborne". But they don't. Residences ain't built like the World Trade Center coming down straight as a pile-driver. Failed floor nearly always tilts.

    Sure, but he's talking about 'a few graduations' on a precision level. A residential floor tilting prior to imminent failure would be much more than that. You go ahead and spread your limitless wisdom all around, after all a 134 year old should be heard. (That's about the age you'd have to be to have all the decades of experience in all the different fields you claim.)

    Its a bit out of character for me to pop off, but I get tired of your smug, arrogant blather.

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    What is underneath the shop area?

    defines what a most appropriate solution would be

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    Is the ceiling underneath the lathe open to the joists? If so, sheets of plywood glued and screwed to the bottom of the joist will effectively turn the joists from T beams to I beams. Stiffness and bending of a beam is related to the second moment of inertia. If you assume a glued and screwed 3/4" plywood floor on 2x10 open joists, the moment of inertia of a single joist section is about 278 in.^4. Adding a glued and screwed skin of 3/4" plywood to the bottom of the joist system increases the moment of inertia to about 738 in^4. It's a lot more complicated than this, but it gives you a general idea of the impact of this type of reinforcement. Deflection will be reduced by about 60%.

    Sheetrock will provide some improvement over exposed joists, but far less than plywood.

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    Quote Originally Posted by Gordon Heaton View Post
    Sure, but he's talking about 'a few graduations' on a precision level. A residential floor tilting prior to imminent failure would be much more than that. You go ahead and spread your limitless wisdom all around, after all a 134 year old should be heard. (That's about the age you'd have to be to have all the decades of experience in all the different fields you claim.)

    Its a bit out of character for me to pop off, but I get tired of your smug, arrogant blather.
    "Tired"? So take a nap and come back refreshed?

    Whilst your silly behaviour doesn't bother me at all. I even encourage it. Not all useful information is equally welcome, anywhere, any time, yours or mine, either one.

    Near-as-dammit EVERYTHING I know has been - and continues to be - learned from OTHERS. Cut-off the input, cut-off whatever it is they know that I do not YET know. I'm far too greedy to go a-hating or holding grudges for more than a short while.

    Hurts me, not the other guy. Where's the gain in that?

    Whatever else, then, I must have acquired more patience, tolerance, or willingness to listen?

    And it's coming up 150 years "equivalent", thanks. Some of us - fully ambidextrous - just don't need as much sleep as others. Go ogle "Dolphin sleep".



    Carry on.

    BTW.. He's close to the wall. Wood gives loud warning before failing in bending. Shear at the typical couplings used? Not so much warning atall.

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    Unless the total deflection due to the weight of the machine and steel plate is excessive in terms of sheer amount of sag (did we ever learn what size joists are under the floor?) I would ignore it so long as the machine moves as a unit and isn't twisting during the slight deflection when you stand near it. If that isn't happening, three level divisions is what? .0015" per foot deflection? Who cares.

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    Quote Originally Posted by Nitromahn View Post
    Okay guys, I get the point. Nothing I can do about the place it's in, but I'll go the cheap route before I spend too much money. In other words, gluing in a few more sheets of flooring should stiffen it. I need to give this a few days to cogitate on it.
    I think that spreading flooring or plates on top of a springy floor will not result in a stiffer base for your lathe. I have a 3500 pound lathe mounted on a 1.125" thick plywood floor and it is rock solid. BUT, the 16"-on center 2X8's under the plywood are supported by 6X8 posts set on concrete pads that distribute the load to a well-bedded 4" concrete slab 7' below. The posts are strategically located where the feet of the lathe contact the shop floor. The load carrying capacity of the vertical timbers set on concrete is orders of magnitude greater than sheeting spanning the base of your lathe.

    I think the answer to your problem lies in supporting the joists solidly from below.

    Denis

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    Quote Originally Posted by gustafson View Post
    What is underneath the shop area?

    defines what a most appropriate solution would be
    Too true. Marquette Building, Chicago's "loop". Famously well built in its day. But that was a long time ago.

    Great place for my employer to site a Joolry Store.

    By the time the RPE, structural guy, and City Engineer / inspectors had given me what I needed to send the riggers in with 5800 Avoir worth of Mosler TRTL30 safe?

    They had to sign a long-term lease on a carpark space directly under the vault, grout on a heavy steel plate, run a heavy column up to a second plate grouted right under the safe!

    Getting it INTO to that spot was a major project, too! Temporary reinforcement had to be placed along the whole route of travel, then removed.

    All part of what they do, one of Illinois best rigging firms of the era. Living legends among the makers of safes and vaults. Mosler is how I found them.

    Experienced and superbly competent at it.

    Free? Not so much!

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    My old home shop had a wooden floor with a crawl space. I used several automobile screw jacks in the crawl space to steady the floor. Worked well.

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