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  • Rollie's Dad's Method Help?

    OK, I've read several threads on "leveling" a lathe, and I understand it's not necessary to level, just necessary to get everything in a horizontal plane.

    My question is, is RDM for aligning the headstock with the ways, and tailstock? Horizontal and vertical alignment by adjusting the headstock? Or is he talking about shimming the "feet" of the lathe in his discription to achieve alignment?

    My lathe is a 14X40 so I only have 4 "feet" instead of six for larger lathes. I guess I'll start by making some "jack bolts" to insert under the "feet".

    thanks,
    Ken

  • #2
    RDM's method is just about eliminating the twist in the bed - shimming adjusting the feet. Visualize an imaginary line that's the lathe spindle centerline projecting straight out down the bed towards the tailstock. Now imagine that the bed is a little twisted as though the tail end was unscrewed. As the carriage progresses down the bed towards the tail the tool is going to be pulled a little away from the centerline and just a teensy bit down. That's the quality that the RDM method is trying to measure and allow you to correct.
    .
    "People will occasionally stumble over the truth, but most of the time they will pick themselves up and carry on" : Winston Churchill

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    • #3
      I would not use "rollie's dad" method on any lathe other then a very light bench lathe like a small short South Bend..

      IMO using that method on a larger lathe is useless..
      Precision takes time.

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      • #4
        Just checked RDM

        Just checked my lathe using RDM. Using a 30" hydraulic cylinder ram that measured 1.001" on both ends. I got .004" of run out in the horizontal measurement, and .006" in the vertical.

        Being I just got it back into position I think I'll let it set for a few days and settle in before trying for anything better.

        Also only got .0005" run out on the 3 jaw chuck. Very happy with that, I wonder if it is the original Taiwan or aftermarket. I'll have to check.

        thanks,
        Ken

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        • #5
          RDM can measure the twist, IF you already KNOW that the headstock is aligned.

          OR

          RDM can measure the alignment of the headstock, IF you already know the bed is level / not twisted.

          RDM is all "internal", all "self referencing". You need an external reference, like a level, to do the whole job.

          In fact, RDM is just a fiddly and error-prone replacement for the "two collars" test, and to make matters worse, it is not a test of actual operation (which the collars test IS).

          Don't make the mistake of thinking it is magic hidden knowledge of some sort. It's just a test of the relation of spindle axis to bed, and probably not the best one, at that.
          1601

          Keep eye on ball.
          Hashim Khan

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          • #6
            The RDM has its vociferous adherants but in fact it's a waste of time advanced by the ignorant but enthusiastic to - in all good faith, BTW - innocently deceive the ingnorant but equipment poor. The RDM seems simple and effective - and it is in a limited way - but most of its appeal lies in the hocus-pocus facor. By the time you go through all the interations you still don't know what you have. The RDM is time consuming and non-quantitive, except in the final cuts.

            There is one inescapable fact about the Rollie's Dad's Method: no skilled equipment re- builder, millwright, production or job shop, or manufacturer uses it or any method like it to align their machine tools.

            The next question is: if no competent craftsman uses RDM, why should you?

            A level, a two collar test or proof bar, basic mechanic's tools, etc, and cutting tests yields the best results in aligning a lathe to "test sheet ready " in the least time. If you don't have this minimum equipment, round it up. You will need it for annual checks and new machine installations anyway even in the home shop. With these one man can set up and align a new lathe 20" and smaller to factory specs in a couple of hours, and a worn lathe to best compromise in 4.
            Last edited by Forrest Addy; 05-20-2012, 07:15 PM.

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            • #7
              I believe I was the one who suggested "searching for Rolleys Dad's Method" in another thread. Perhaps I should have been more specific. I said to look it up, but I did not say to actually use it. You will find a great amount of information in those posts, much of it better than RDM. I am sorry if I caused any confusion.
              Paul A.

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

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              • #8
                Paul. I kinda gathered that when I skimmed your response. However mention of RDM in any contest seems to bring its adherants out of the woodwork and I wanted to scotch building enthusiasm. Hence, my red-eyed vigor.

                If my words put you in a bad light, I'm sorry. That wasn't my intention. Call it friendly fire.

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                • #9
                  Rdm

                  I did a search last week of this site and I think the key words were "lathe level" or "lathe leveling".

                  There was a lot of discussion on 3-4 threads about the lathe not actually needing to be level at all "lathes on ships, etc." However it was simply a means a putting everything into a measureable horizontal plane. I understand and agree with all of this. However, in one of the post RDM was mentioned and the method seemed simple enough, and seemed to make sense. Since then I have read other post in other threads/forums and looking for some advice on whether it was meant to shim the headstock or shim the feet of the lathe? Not trying to start a heated discussion. Never realized that as some have said that it is for "mini-lathes".

                  I'll look up the two-collar method and see what that involves.

                  thanks,
                  Ken

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                  • #10
                    Two collar method

                    Did another search on the "two collar method" trying to digest everything for now.

                    I'll start by leveling the lathe and work from there.

                    thanks,
                    Ken

                    Comment


                    • #11
                      Sorry I never heard of Rollie or his Dad who are they or are they an American myth that is unknown here????Alistair
                      Please excuse my typing as I have a form of parkinsons disease

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                      • #12
                        Be glad you never heard of Rollie's Dad's Method. IMO, it is designed to be used on used lathes by those who don't have the proper level. You place a bar in the chuck, and start taking cuts at each end of the bar. Measure the ends and make adjustments by placing shims under the offending foot of the lathe. It struck me as a pure guessing game, that would take an enormous amount of time with very questionable results. What the method does is to deliberately twist the bed so that one can turn a parallel shaft for that particular distance, then you get to do it over again for a different length. To me it's pure hocum, or as Forrest says "hocus-pocus".
                        It's similar to the 2 collars test, but a level is not used, and as result there are no controls. IMO, it's a scam perpetrated on the unsuspecting, looking for the magic cure.
                        I read the instructions several times before I figured it out.

                        Using 2 levels, one to rough the lathe in, and the other with with .0005" graduations to fine tune, I generally can get a lathe leveled in under an hour. When I relocated to my new shop, I taught my apprentice son how to level the lathe. I was the wrench turner and he told me which way to turn the wrench. He had never used that level before. I thought it would take 2 hours, but 45 minutes later the lathe was within a couple tenths end to end. The lathe has 4 leveling screws at each end.
                        Harry
                        Last edited by beckley23; 05-20-2012, 06:15 PM.

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                        • #13
                          Sorry I never heard of Rollie or his Dad who are they or are they an American myth that is unknown here??"


                          "here"? Where is that?
                          Last edited by tdmidget; 05-20-2012, 07:16 PM.

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                          • #14
                            The topic under discussion here is properly called "Rollie's Dad's Method of Lathe Alignment" and the instructions may be found here:

                            http://neme-s.org/Rollie's_Dad's_Method.pdf

                            Before this discussion drifts any further into the realm of name calling let's all recognize that Rollie's dad used this method with fine results for him and he was a talented and respected tool maker in Massachusetts.

                            I am somewhat surprised that laser interferrometers have not yet been mentioned.

                            If you don't think RDM is right for you then please don't feel obliged to use it!

                            I try not to get worked up by things like this but Rollie is a long time friend and talented HSM craftsman. His dad was a great fellow as well and is mised by all who knew him.
                            Last edited by Errol Groff; 05-20-2012, 07:35 PM.
                            Errol Groff

                            New England Model Engineering Society
                            http://neme-s.org/

                            YouTube channel: http://www.youtube.com/user/GroffErrol?feature=mhee

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                            • #15
                              Originally posted by customcutter
                              I did a search last week of this site and I think the key words were "lathe level" or "lathe leveling".

                              There was a lot of discussion on 3-4 threads about the lathe not actually needing to be level at all "lathes on ships, etc."
                              Bless your heart! Lathe leveling is one of those religious items like "billet", aircraft aluminum, and whether to mash knurls

                              You're a lot better off reading a description of the two collar method in a machinist text than to try and filter the threads here, IMHO...
                              Most texts tell you to level the lathe, then adjust the legs on the lathe until the collars match. HTRAL, for example:

                              "The leveling may be perfected by adjusting the shims under the front and back legs until the collars on the test piece are turned the same diameter."

                              Rollie's Dad's method skips the leveling, and goes straight to shimming.
                              Last edited by lazlo; 05-20-2012, 07:56 PM.
                              "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

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