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Impressive $20 brake rotor for tramming the mill

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  • #31
    This thread is rattling down the same path of esoterica as the Poor Man's Surface Grinder thread, but before it loses all value to over-intellectualizing I'll just add that I picked up a similar rotor at the local parts store and am very pleased with how it works with my Asian mill using my Asian coaxial indicator and Asian 1-2-3 blocks. My mill is now trammed as good as it is ever going to be and it was utterly painless thanks to this simple idea.

    Another example of thinking outside the box and coming up with an adequate solution using non-typical components. Such solutions are what makes the H in HSM meaningful.
    Last edited by dp; 08-19-2008, 03:27 AM.

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    • #32
      Originally posted by dp
      This thread is rattling down the same path of esoterica as the Poor Man's Surface Grinder thread, but before it loses all value to over-intellectualizing
      The thread was purely on-topic until someone posted trigonometry about worn knees.

      If you want to Get 'R Done, just tram off the table. You don't need a disc rotor.
      "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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      • #33
        I really like the idea of using cheap ordinary every stuff to do things that might take $$$$ if you bought the "real thing". The brake disc is classic.
        Its cheap and available! I got a piece of thick float glass from a old coffee table in the attic...

        E.g. you want an oil proof, waterproof, cutting fluid proof, thin tough, high temperature chip resisting (260C, 500F) , low friction/no-chafe, washable membrane to protect your machine ways... This obviously needs a high tech matieral of the finest kind


        Try a teflon baking sheet from your local hardware store or supermarket or steal one from SWMBO if you dare. It meets all the requirements


        Need a high voltage connection to pass into a steel pressure container...




        try a spark plug! available everywhere!


        Do anyone have anymore?

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        • #34
          extruded ALu bar is parallel?

          Heres another one a bit more on topic - Because I didnt have some parallels to hand and the job didnt really need to be accurate I used some 1" by 3/4" extruded aluminum solid bar lying in my metal store instead. When I micced the resulting job (as you do even if you only the nearest mm) I found it was within a 001" of being square and parallel then when I checked the "new Ally parallels" I was using, I found they are within 0.0002 of being parallel and 0.001 of specified size in each dimension

          So why do I need to speed $$$$ on ground parallels?

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          • #35
            Originally posted by lazlo
            The thread was purely on-topic until someone posted trigonometry about worn knees.

            If you want to Get 'R Done, just tram off the table. You don't need a disc rotor.
            My tiny mill has a tiny table in the Y dimension - this idea provides a nice workaround for that. The only worn knees in my shop are affixed to me. BTW, that table needs to be surface ground and I'm not going to do that on my saw

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            • #36
              Originally posted by dp
              BTW, that table needs to be surface ground and I'm not going to do that on my saw
              Oh, come on now Dennis -- just chuck a cup wheel in a drill press and Get 'R Done!
              "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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              • #37
                Originally posted by lazlo
                Oh, come on now Dennis -- just chuck a cup wheel in a drill press and Get 'R Done!
                Yessir - that should work fine!

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                • #38
                  More tramming.

                  Now excuse me while I butt in and get back to the "right tram but tilted table" bit.

                  I will discuss the "tilting" later.

                  Back to the scenario where (let's say I - me) have my mill spindle trammed to my table and that my table is tilted forward.

                  The previously-mentioned "saw-tooth" effect between adjacent nicely over-lapping circular patterns is not the only "hidden" problem.

                  If the knee is raised to, say, locate an edge or edges or the centre of a hole (in "X" and "Y"), and if the knee is dropped/lowered, the axis of the - lets say hole, the principal is the same for anything - the coincident centres will remain parallel but will diverge to the extent that the quill spindle axis and the axis of the hole are no longer coincident. This will increase as the distance between the initial location height of the knee and the machining positions widen. The converse similarly applies.

                  In this case there will or may well be an unexpected and unexplained alignment error such that an otherwise apparently correctly aligned/located detail/position may not be accurately repeated with the lowering/raising of the "knee". This may well result in a hole drilled or bored by using the quill down-feed, or the knee up-feed not having the same relationship to the referenced edges (used by the edge-finder etc.) as previously aligned or as expected.

                  I have only use a tilt/"sag" in the "knee" in the "Y" plane. The same can occur if the mill saddle or table tilts/"sags" in the "X" plane. There may well be both "X" and "Y" components in which case they may well compose a vector that is between but neither wholly within either or both the "X" nor "Y" planes.

                  A similar effect and situation arises with an improperly aligned and set up column and/or spindle on a vertical mill-drill.

                  All of this matter is directly applicable to situations that may arise in what may for all intents and purposes, a correctly "trammed" milling machine.

                  And yes, a brake disc rotor or similar is quite in order to be used - or not used (your choice) in any of these posts that I make

                  I will discuss these topics further later.
                  Last edited by oldtiffie; 08-18-2008, 11:36 AM.

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                  • #39
                    Originally posted by oldtiffie
                    Now excuse me while I butt in and get back to the "right tram but tilted table" bit.
                    Tiff, if you're going to do that, can you start a new thread?
                    "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

                    Comment


                    • #40
                      Originally posted by oldtiffie
                      Now excuse me while I butt in and get back to the "right tram but tilted table" bit.

                      I will discuss the "tilting" later.

                      Back to the scenario where (let's say I - me) have my mill spindle trammed to my table and that my table is tilted forward.

                      The previously-mentioned "saw-tooth" effect between adjacent nicely over-lapping circular patterns is not the only "hidden" problem.

                      If the knee is raised to, say, locate an edge or edges or the centre of a hole (in "X" and "Y"), and if the knee is dropped/lowered, the axis of the - lets say hole, the principal is the same for anything - the coincident centres will remain parallel but will diverge to the extent that the quill spindle axis and the axis of the hole are no longer coincident. This will increase as the distance between the initial location height of the knee and the machining positions widen. The converse similarly applies.

                      In this case there will or may well be an unexpected and unexplained alignment error such that an otherwise apparently correctly aligned/located detail/position may not be accurately repeated with the lowering/raising of the "knee". This may well result in a hole drilled or bored by using the quill down-feed, or the knee up-feed not having the same relationship to the referenced edges (used by the edge-finder etc.) as previously aligned or as expected.

                      I have only use a tilt/"sag" in the "knee" in the "Y" plane. The same can occur if the mill saddle or table tilts/"sags" in the "X" plane. There may well be both "X" and "Y" components in which case they may well compose a vector that is between but neither wholly within either or both the "X" nor "Y" planes.

                      A similar effect and situation arises with an improperly aligned and set up column and/or spindle on a vertical mill-drill.

                      All of this matter is directly applicable to situations that may arise in what may for all intents and purposes, a correctly "trammed" milling machine.

                      And yes, a brake disc rotor or similar is quite in order to be used - or not used (your choice) in any of these posts that I make

                      I will discuss these topics further later.
                      So to summarise you are saying that not only should the Z axis be truly orthogonal to both the X and Y axes for all values of X and Y it should be without a varying zero offset (offset) for all X and Y.

                      And you further contend that tramming to a disc only gives you this for a single value of X and Y.

                      This is true - However.
                      I would contend that for most mills the changes in Z offset across X and Y and the variability in orthogonality with variation in X, and Y, only change very slowly with time.

                      Whereas the point changes in orthogonallity can change abruptly and frequently ( head swiveling?, vice swinging etc...) hence the concentration on tramming, a single point check for orthogonality, in this forum.

                      Others have contended that one should concentrate on the variation of orthogonality and offsets to local frames of reference rather than relative or more universal frames.

                      I would however contend that the scope of variation of orthogonality and offset should be localised to the problem under consideration rather than to specific general or local frames of reference.

                      To summarize "WHAT EVER GETs 'ER DONE"

                      (With thanks to Sir Humphrey Appleby and Bernard Wooley at the Department of Administrative affairs )
                      Last edited by derekm; 08-18-2008, 12:51 PM.

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                      • #41
                        "A brave decision Derek"
                        to paraphrase Sir Humphrey

                        (and that was the Department of Administrative Affairs)
                        Just got my head together
                        now my body's falling apart

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                        • #42
                          Originally posted by Swarf&Sparks
                          "A brave decision Derek"
                          to paraphrase Sir Humphrey

                          (and that was the Department of Administrative Affairs)
                          Thank you and I stand corrected. I must hurry off to number 10

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                          • #43
                            Originally posted by derekm
                            I would however contend that the scope of variation of orthogonality and offset should be localised to the problem under consideration rather than to specific general or local frames of reference.

                            To summarize "WHAT EVER GETs 'ER DONE"

                            (With thanks to Sir Humphrey Appleby and Bernard Wooley at the Department of Administrative Affairs )
                            Friggin' hilarious! Thanks Derek!
                            "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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                            • #44
                              "I must hurry off to number 10"

                              Give my regards to the chancellor at number 11
                              Just got my head together
                              now my body's falling apart

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                              • #45
                                Originally posted by derekm
                                Then have you got a technique for checking if the head goes out of tram mid cut
                                or at the end of each cut - and if you dont would you want one if you could?
                                Not yet,but I am getting there.

                                There used to be a device called a "Tram monitor"it was too simple a design and too easy to build so I don't think they sold many

                                Basically it consisted of a sqaure block fixed to the bottom of the B-port mills belt case under the motor.Bellow that were two indicators fixed to the ram set at 90* to each other.

                                In use the mill was trammed in and both indicators set to 0.

                                If the mill's head was kicked out of tram a quick glance at the indicator dials would tell tale.

                                Even better setting the mill back in tram could be quickly done by by setting the head back until both indicators read 0.

                                The company that made them got $349 each which was a bit much considering it was simple and didn't include the indicators.I don't know if they are even selling them anymore.
                                Last edited by wierdscience; 08-18-2008, 02:05 PM.
                                I just need one more tool,just one!

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