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Re: Alignment method.

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  • John Pitkin
    Pat, Good idea to check the table first. I don t think you are referring to flatness (surface of the table). You probably mean the alignment of the table
    Message 1 of 10 , Nov 1, 2006
      Pat,

      Good idea to check the table first. I don't think you are referring
      to "flatness" (surface of the table). You probably mean the alignment
      of the table with the ways. I'm curious as to how you corrected the
      table.

      Either the ways and dove tails must be scraped; or, you must grind
      the table. Neither is any fun.

      So which method did you use?

      JP

      --- In GrizHFMinimill@yahoogroups.com, "pat02uk" <patrickrundle@...>
      wrote:
      >
      > One thing not taken into account is the flatness of the mill table.
      >
      > Before alignment it would be wise to check the table by mounting a
      > dial gauge in the spindle and winding the table in both x and y
      > directions under it.
      >
      > The reason I say this is because my table was way off (0.16mm
      > variation from one end to the other).
      >
      > This may have been a bad example but obviously tramming and spindle
      > alignment make no sense if this isn't attended to first.
      >
      > Pat
    • pat02uk
      The problem is a variation of the thickness of the table measured between the top table surface and the bottom surface bearing on the ways. As far as I can see
      Message 2 of 10 , Nov 1, 2006
        The problem is a variation of the thickness of the table measured
        between the top table surface and the bottom surface bearing on the
        ways. As far as I can see this is the only way to explain the
        measurements I made (confirmed later by direct measurement).

        I think the first thing to do would be to lap the table/ways/dovetails
        together after which it is probably safe to consider the ways to be flat.

        As to correction of the table, grinding or scraping the top surface
        seems the way to go.

        I think grinding would be expensive and I've never tried scraping. So
        my method was somewhat more basic and involved lapping and judicious
        use of diamond stones. However, I managed to improve the situation
        from a 0.16mm variation to 0.03mm fairly quickly. I think I could
        better this but it would take much longer to do.

        I have been puzzling for some time over the setting up of one of these
        mills to produce reasonable accuracy and performance. Particularly the
        question 'where do you start'!

        Pat

        --- In GrizHFMinimill@yahoogroups.com, "John Pitkin"
        <cedarcreekranch@...> wrote:
        >
        > Pat,
        >
        > Good idea to check the table first. I don't think you are referring
        > to "flatness" (surface of the table). You probably mean the alignment
        > of the table with the ways. I'm curious as to how you corrected the
        > table.
        >
        > Either the ways and dove tails must be scraped; or, you must grind
        > the table. Neither is any fun.
        >
        > So which method did you use?
        >
        > JP
        >
        > --- In GrizHFMinimill@yahoogroups.com, "pat02uk" <patrickrundle@>
        > wrote:
        > >
        > > One thing not taken into account is the flatness of the mill table.
        > >
        > > Before alignment it would be wise to check the table by mounting a
        > > dial gauge in the spindle and winding the table in both x and y
        > > directions under it.
        > >
        > > The reason I say this is because my table was way off (0.16mm
        > > variation from one end to the other).
        > >
        > > This may have been a bad example but obviously tramming and spindle
        > > alignment make no sense if this isn't attended to first.
        > >
        > > Pat
        >
      • John Pitkin
        Pat, Certainly, 0.03mm tilt in 220mm travel is pretty good. If you know the error exists, simply shim the low end. I shim almost all jobs requiring precision,
        Message 3 of 10 , Nov 1, 2006
          Pat,

          Certainly, 0.03mm tilt in 220mm travel is pretty good. If you know
          the error exists, simply shim the low end. I shim almost all jobs
          requiring precision, anyway, because my vise has more error than that.

          For the permanent fix,surface grinding is pretty inexpensive. Just
          mark the table where its too high and a shop can grind the table in a
          few minutes. The last time I had a shop do a job it was under USD $50
          to resurface a 10 x 30 inch jointer extension table. This little mill
          table should cost about half that.

          I think that's a lot easier than trying to realign the dove tails and
          ways. Sure, you can lap the ways for a smooth slide, but if they are
          still out of alignment it means having to machine both the ways and
          the dove tails, a very difficult job.

          John Pitkin


          --- In GrizHFMinimill@yahoogroups.com, "pat02uk" <patrickrundle@...>
          wrote:
          >
          > The problem is a variation of the thickness of the table measured
          > between the top table surface and the bottom surface bearing on the
          > ways. As far as I can see this is the only way to explain the
          > measurements I made (confirmed later by direct measurement).
          >
          > I think the first thing to do would be to lap the
          table/ways/dovetails
          > together after which it is probably safe to consider the ways to be
          flat.
          >
          > As to correction of the table, grinding or scraping the top surface
          > seems the way to go.
          >
          > I think grinding would be expensive and I've never tried scraping.
          So
          > my method was somewhat more basic and involved lapping and judicious
          > use of diamond stones. However, I managed to improve the situation
          > from a 0.16mm variation to 0.03mm fairly quickly. I think I could
          > better this but it would take much longer to do.
          >
          > I have been puzzling for some time over the setting up of one of
          these
          > mills to produce reasonable accuracy and performance. Particularly
          the
          > question 'where do you start'!
          >
          > Pat
          >
          > --- In GrizHFMinimill@yahoogroups.com, "John Pitkin"
          > <cedarcreekranch@> wrote:
          > >
          > > Pat,
          > >
          > > Good idea to check the table first. I don't think you are
          referring
          > > to "flatness" (surface of the table). You probably mean the
          alignment
          > > of the table with the ways. I'm curious as to how you corrected
          the
          > > table.
          > >
          > > Either the ways and dove tails must be scraped; or, you must
          grind
          > > the table. Neither is any fun.
          > >
          > > So which method did you use?
          > >
          > > JP
          > >
          > > --- In GrizHFMinimill@yahoogroups.com, "pat02uk" <patrickrundle@>
          > > wrote:
          > > >
          > > > One thing not taken into account is the flatness of the mill
          table.
          > > >
          > > > Before alignment it would be wise to check the table by
          mounting a
          > > > dial gauge in the spindle and winding the table in both x and y
          > > > directions under it.
          > > >
          > > > The reason I say this is because my table was way off (0.16mm
          > > > variation from one end to the other).
          > > >
          > > > This may have been a bad example but obviously tramming and
          spindle
          > > > alignment make no sense if this isn't attended to first.
          > > >
          > > > Pat
          > >
          >
        • yenomon70
          I took your advice and aligned my mill head etc. It was off. I agree with you ..it does take patience. At the end of this alignment process it dawned on me.
          Message 4 of 10 , Nov 4, 2006
            I took your advice and aligned my mill head etc. It was off.
            I agree with you ..it does take patience. At the end of this
            alignment process it dawned on me. Why not tighten the bolts snugly
            then reinstall the head on the column and recheck. If it is out of
            alignment it won't be by much so then give it a whack with the mallet
            until it comes out on the nose. Then remove it and tighten the bolts
            vigorously. Of course you can combine your daily weight lifting and
            just keep removing and replacing the head
            Thanks John
            Bob

            --- In GrizHFMinimill@yahoogroups.com, "John Pitkin"
            <cedarcreekranch@...> wrote:
            >
            > Pat,
            >
            > Good idea to check the table first. I don't think you are referring
            > to "flatness" (surface of the table). You probably mean the
            alignment
            > of the table with the ways. I'm curious as to how you corrected the
            > table.
            >
            > Either the ways and dove tails must be scraped; or, you must grind
            > the table. Neither is any fun.
            >
            > So which method did you use?
            >
            > JP
            >
            > --- In GrizHFMinimill@yahoogroups.com, "pat02uk" <patrickrundle@>
            > wrote:
            > >
            > > One thing not taken into account is the flatness of the mill
            table.
            > >
            > > Before alignment it would be wise to check the table by mounting a
            > > dial gauge in the spindle and winding the table in both x and y
            > > directions under it.
            > >
            > > The reason I say this is because my table was way off (0.16mm
            > > variation from one end to the other).
            > >
            > > This may have been a bad example but obviously tramming and
            spindle
            > > alignment make no sense if this isn't attended to first.
            > >
            > > Pat
            >
          • joelblatt_32952
            I did the same job on my mill. I was dreading the job, but wanted to remove the gears after converting to a belt drive so the alignment discussion gave me the
            Message 5 of 10 , Nov 6, 2006
              I did the same job on my mill. I was dreading the job, but
              wanted to remove the gears after converting to a belt drive so the
              alignment discussion gave me the excuse to dive in. I had already
              used shims at the base of the column to align it fore and aft and
              fortunately the head wasn't off from the column in that direction.
              I really appreciate the suggestions, especially the "tighten some what and
              swat with a mallet" advice - that really worked - I only had to take
              the head off a couple of times till I got the final alignment within a
              thousandth and a half on both axes. I do have a suggestion - I use
              a Micro-tram plate to do the final alignment with a vise installed -
              it really makes tramming easy once the column is aligned....Joel in Florida
              =============
              --- In GrizHFMinimill@yahoogroups.com, "yenomon70" <yenomon70@...> wrote:
              >
              > I took your advice and aligned my mill head etc. It was off.
              > I agree with you ..it does take patience. At the end of this
              > alignment process it dawned on me. Why not tighten the bolts snugly
              > then reinstall the head on the column and recheck. If it is out of
              > alignment it won't be by much so then give it a whack with the mallet
              > until it comes out on the nose. Then remove it and tighten the bolts
              > vigorously. Of course you can combine your daily weight lifting and
              > just keep removing and replacing the head
              > Thanks John
              > Bob
              >
            • Arved
              ... OK, for those of you who ve done this, what sort of square did you use? I have visions of a 12 machinist square being required. Thanks, - Arved Thanks, -
              Message 6 of 10 , Feb 1, 2011
                From an ancient posting (and since then a PDF file hosted here) from the great John Pitkin:

                > Setting the column
                >
                > Using a framing square, I adjusted the column to approximately
                > vertical. Not perfect, but it's a starting point.
                >
                > Then, I use an accurate square to get the column vertical and
                > perpendicular to the table. With the square clamped to the table and
                > a dial indicator attached to the head with a magnetic base (not
                > attached to the quill), run the head up and down (z axis) checking
                > distance to the square. Check both left right tilt and fore/aft tilt.
                > This will check the column for perpendicularity.

                OK, for those of you who've done this, what sort of square did you use? I have visions of a 12" machinist square being required.

                Thanks,
                - Arved

                Thanks,
                - Arved
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