Leveling lathe on uneven floor before a CNC retrofit. Suggestions?

Discussion in 'CNC Machines and Conversions' started by Uguessedit, Jul 29, 2018.

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  1. Aug 4, 2018 #41

    goldstar31

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    The link has been repeated and repeated 'ad nauseum'. 'Cleeve' ( Kenneth C Hart) wrote in Model Engineer regarding 'His Myford spindle/ headstock which had been aligned by Myford- with pushers and would withstand the attention of a tank. Hart had, of course raised the height of his ML7 by a quarter of an inch! Again, George Thomas also in Model Engineer and then in his books, scotched the tailstock height mystery. Tom Walshaw writing as Tubal Cain discussed the continual shifting of the base ground for his lathe- lathes when he moved out from Darlington to Penrith.

    There is only only demerit in all this----- No one can be minded to read it and put it into practice.

    As I wrote earlier--------------------

    Norm
     
  2. Aug 5, 2018 #42

    Cogsy

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    So what you're saying here is you don't know the reason so can't give it, but somebody once wrote it down so we should just do it? I can't see any reason to purposely misalign the headstock. It should be as parallel as possible. Although nothing can be absolutely perfect, with the precision available to us today, we should be able to get reduce the parallelism error to the point where any concavity/convexity facing effects are nullified by surface finish. In days gone by with more limited precision measuring equipment available, I assume concessions had to be made. It's these sorts of reasons that new editions of books/new books are produced and we don't blindly follow old texts.
     
  3. Aug 5, 2018 #43

    goldstar31

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    No !,I was saying that the the manufacturers of Myford deliberately set the headstock out of alignment .It was followed by the old experts AGREEING.

    In the case of the headstock, the set off compensates for the force of cutting tools! Thomas in his inimitable but pedantic way discusses the height of the tailstock being above the centre line.

    As for access to new books- or revised books, it hasn't happened YET.I would add- to my knowledge.

    What can be said is that I have actually restored several lathes over the years and heeded the advice of those who have gone before.

    Earlier in this, I mentioned the word 'reference' and whilst this is constantly referred to in Connelly's classic tome,- Machine Tool Reconditioning, no one has picked up what is or was the essential part of restoring a machine tool.

    Today, machine tools???? Few of us of had the opportunity to go where they bare actually made. When I am in HongKong or wherever, I have more important things to do and to spend a holiday traipsing around factories. However, I do know -again from practical experience- how modern cars are initially optically aligned and again, how they are corrected after damage.

    I can only hope that this might have cleared some of the misconceptions that seem to crept in- as old wives tales and which, in my opinion- are more than questionable. For me, in the very dim twilight of my life, have probably spent more of what I somewhat selfishly need to know. Hopefully, it is a democratic forum and different opinions should be discussed.

    My kind regards to youall


    Norman
     
  4. Aug 5, 2018 #44

    Hopper

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    Myford's factory inspection sheet specifies the far end of a six-inch test bar in the headstock spindle should point between zero and .0006" toward the direction of tool pressure, ie toward where the operator stands.
    Connelly in MC Tool Recon. allows plus or minus .0003" at the end of a 12" test bar for a toolroom lathe.
    Either of these might be hard to achieve on a lathe with wear on the bed that could easily exceed half a thou (by a factor of several times!).
     
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  5. Aug 5, 2018 #45

    goldstar31

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    Cheers--- confirmation!

    For what is worth in this case, I suspect that there is nothing wrong with the poster's lathe-- other than a slight adjustment of the tailstock- by a gnat's c*** or midge's whisker.

    What probably is necessary is the ability to understand how a bench lathe. should be arranged- and probably how the stand should constructed.

    For the record, my SiegC4 is sitting quite comfortably on an old office desk which just happens to be on a chipboard floor in my study in my bungalow. NOTHING is bolted down.



    TTFN

    Norm
     
  6. Aug 5, 2018 #46

    Hopper

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    Yes, ironically I have the Mighty Drummond solid mounted on a specially made stand of heavy heavy angle iron and four-inch channel braced directly ffrom the lathe's mounting bolts to the floor, where it is also bolted. But it is not as accurate a lathe as my loose-mounted Myford sitting on two blocks of softwood on a wobbly sheet metal and 1" square tube stand set loose on an uneven concrete floor. Apparently the bed is as untwisted as the day it left Nottingham and just sits there floating about and doing what it is supposed to do. The closest thing to a level that has ever been near it would be a glass of rough red filled to the brim stood on the bench next to it while considering the next move. It seems to have worked. Certainly within a hare's breath of a gnat's whatever.
     
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  7. Aug 6, 2018 #47

    bazmak

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    Usually use 1" dia bar sticking out about 8" With the light cuts involved you wont get any measurable deflection
    Maybe slightly from the chuck/Hstock bearings depending on condition.I test bar and dial indicator will give more accurate results
    but the light cuts give more of an indication during the cutting process
     
  8. Aug 6, 2018 #48

    Cogsy

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    My thoughts exactly Baz. Setting up an intentional nominal misalignment on a headstock to account for cutting forces which vary according to tool geometry, depth of cut, tool sharpness, type/diameter/length/support of material and whatever other factors come in to play is an exercise in futility and not something we need to concern ourselves with, in my opinion obviously.
     
  9. Aug 6, 2018 #49

    goldstar31

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    I rather think that the futility of it is the fact that 'we' have given freely of our time and our knowledge to no avail.
    'We' have had our learned discussion but as for the poster, we are left guessing as he hasn't deigned to return.
    Clearly, there are recent postings about 12 x37 lathes. One wonders what their reasons are for not posting

    For what it is worth, an eminent authority in both full size and model engineering wrote to me. We had been discussing full size ships etc. Somewhat bitterly he wrote of the same old daft questions and receiving the same old daft answers.

    His views and- I'm seriously tending to agree with him more and more. Last time that I heard from him he had cancer but despite it all, was building a full size steam loco!

    Regards

    Norm
     
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  10. Aug 6, 2018 #50

    GaryLa

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    I usually pour a 4 inch minimum to 8 inch thick "footer" of concrete.

    Using 2x8s as a frame, a little larger than the machine's footprint.

    I vibrate it and it finds its own natural level. This "buffers" me from the original floor's problems and gives me a stable, level base.
     
  11. Aug 6, 2018 #51

    Anatol

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    Hello Norm

    Standing midway between you and the OP, (capable old hand in the skills I have, but only now getting into machining seriously) I have sympathy for both sides. Having been on several forums I think this is par for the course. Like so many other internet thingies, you have No Idea who your'e talking to, might be a beginner or a professor... (Who knows what is going on in his life? I recall someone criticizing me for being offline too long - I'd been dealing with adeath in the family!).

    "Earlier in this, I mentioned the word 'reference' and whilst this is constantly referred to in Connelly's classic tome,- Machine Tool Reconditioning, no one has picked up what is or was the essential part of restoring a machine tool."

    Nice reference, but its $300 on amazon - out of my budget.
    still learning,
    A
     
  12. Aug 6, 2018 #52

    goldstar31

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    As far as my memory is holding out at 88 years, this topic was flogged and flogged some way back. What was also there was how to download Connelly's Machine Tool Reconditioning. It's a wonderful book and to be recommended to those who have difficulties in sleeping. Maybe Georg Schlessinger 's various editions on testing machine tools is somewhat easier going.

    Moving slightly 'off topic' but I hope constructive is Robert H Smith's Advanced Machine Tool Work. I had a copy, gave it away to someone who didn't even acknowledge but it is there on the 'net. Expect 5 or 600 pages but there are wonderful snippets on how to create angles from the periphery of abrasive wheels - by simple packing.
    Great when one doesn't have a full blown tool and cutter grinder!

    Any use????

    Norm

    As a Postscript, I attempted to price Connelly but note that on my computer in Google there is the PDF to download-- or put you to sleep:oops:
     
    Last edited: Aug 6, 2018
  13. Aug 7, 2018 #53

    Hopper

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    Yeh, I think lathe levelling/alignment threads are in danger of becoming like the endless dino vs synthetic oil threads on motoring and motorbiking forums.
    Getting to the stage where one has to wonder if it's worth, as your old mate commented, giving the same old answers to the same old questions.
    I might be better off out in my shed spending my time doing the impossible and turning out true and parallel work on a vintage piece of junk perched on two wooden blocks. (In fact, I know I would be!)
     
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  14. Aug 7, 2018 #54

    goldstar31

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    I've given you 'a like' because I am at the point of becoming a 'lurker'.
    In the past few minutes, I have yattered with a friend of my late wife and whose husband has a Myford ML7 in his flock wallpapered hobby room. She is paying- bitterly for residential music courses and is not getting value for her hard earned cash. She is, by the way, a teacher herself.

    One wonders what the reaction would be if posters seeking information had to pay the rate for the job and not to be ignored after a helper gives for free and is studiously finally ignored.

    Norman
     
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  15. Aug 7, 2018 #55

    BaronJ

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    Hi Norman, Guys,

    That seems to be becoming the way of the world...
     
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  16. Aug 11, 2018 #56

    Wizard69

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    Im not sure if i can add much to this thread. In any event if the lathe bed is twisted you will need a substantial foundation to fasten it to to untwist it! I really see no way around this.

    For me the bigger question would be is the bed actually twisted? Sadly beds do twist, often on newer lathes, as the castings relax internal stresses. This can require substantial effort to correct.

    This brings us back to the "foundation" which on larger lathes would be a substantial concrete pad. On a smaller lathe you might get by with a concrete floor but concrete floors vary widely in quality. Really small lathes can be untwisted on substantial tables. In all cases your foundation needs to be stiff enough to resist the lathes desire to twist.
     
  17. Aug 12, 2018 #57

    Uguessedit

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    Sorry guys I’ve been busy. I should’ve followed up earlier. Everything went well. After dialing the tailstock in we have a beautiful turning beast. She has been solid and I have been watching every few days to check for floor settling. It seems to have resolved flashing around all the edges and it’s certainly more stable now. I do plan to eventually build a bigger stronger stand but this will do until that time comes. Very pleased and the comments helped me think through the challenges of an inconsistent sinking floor. While adjusting the tailstock I did have to deal with a cracked cast screw stop and machined one up over an evening and cleaned it all inside and out and reassembled. Like new again. Thanks.
     

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