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new article: X or Y Axis Zero Set on a Mill

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  • Rick
    If you have followed my previous strange journeys, you know that I occasionally go overboard in the area of accuracy. Well, here we go again. This article
    Message 1 of 31 , Dec 30, 2008
      If you have followed my previous strange journeys, you know that I
      occasionally go overboard in the area of accuracy.
      Well, here we go again. This article deals with a method for setting
      zero on my mill such that I can make "accurate" cuts with an end mill.

      I do not claim that this is a proof, but the procedure does seem to work
      well. Time, and your comments, will tell....

      Your questions and comments are welcome.

      See

      http://rick.sparber.org/XYZ.pdf

      Rick Sparber
    • Rick Sparber
      Glenn, Glad to hear that the touch pad works so well. It gives me encouragement to build my own. I have looked at the accuracy of the EEF compared to using a
      Message 31 of 31 , Sep 6, 2009
        Glenn,

        Glad to hear that the touch pad works so well. It gives me
        encouragement to build my own.

        I have looked at the accuracy of the EEF compared to using a high
        quality DTI. With care, I was able to "tune" the position of my EEF
        for zero run out. Then I could expect a repeatable accuracy of about
        0.0002". A lot depends on how clean all surfaces are and how gently
        you can achieve touchdown. One tiny spec of swarf on the surface or on
        the probe and you can forget about accuracy.

        I've never had trouble with EMI on my EEF. Are you using an interface
        circuit or connecting directly to the DRO?

        I've been playing with alignment of my rotary table using my EEF and
        found very good results. I mount a block on the RT's top, crank it
        around the 360 degrees and use the centerline function to find (0,0).
        I have the procedure written up but have not had time to do a final
        check and post it.

        Although I'm technically in retirement, I've just accepted a position
        as adjunct professor at a local community college. I'll be helping to
        teach engineering. I did this as a volunteer last spring but this time
        around they want me to be able to handle petty cash so I must be an
        employee. So much for retirement... It is a lot of fun.

        Rick

        -----Original Message-----
        From: mill_drill@yahoogroups.com [mailto:mill_drill@yahoogroups.com]
        On Behalf Of Glenn N
        Sent: Sunday, September 06, 2009 10:09 AM
        To: mill_drill@yahoogroups.com
        Subject: Re: [mill_drill] new article: X or Y Axis Zero Set on a Mill

        Rick,
        Well since the water tank episode I have had to replace the HVAC in
        the
        house and still haven't finished getting the shop in order. Seems
        life just
        keeps getting in the way of living:)

        Since this message I have built the DRO 350 and installed it on my
        mill.
        The touch pad works very well with the DRO and the accuracy is
        comparable to
        the paper trick. Have you done any testing with it to see how well it
        works
        for you? Sometimes it fails to set or sets on it's own but I haven't
        investigated that yet. I think I need to do something to desensitize
        it a
        bit. I think it is just ambient EMI tripping it but I haven't put the
        scope
        on to see. The shop shelving project is almost finished now so I
        should be
        working in the shop soon instead of on it. How did I ever get
        anything done
        before I retired??

        Glenn
        ----- Original Message -----
        From: "Rick" <rgsparber@...>
        To: <mill_drill@yahoogroups.com>
        Sent: Wednesday, December 31, 2008 12:32 PM
        Subject: Re: [mill_drill] new article: X or Y Axis Zero Set on a Mill


        Glenn,

        Sorry to hear about the water tank. It is always annoying when the
        real
        world intrudes on shop adventure.

        I look forward to your analysis when you have time to get back to your
        shop.

        On one of my past "accuracy binges", I looked very closely at the
        accuracy of a Harbor Freight 8" caliper. I use them on my DRO with
        minor
        modification, on my height gage, and one hand held. I also have one on
        the ways of my lathe. I found them to be far better than the stated
        spec. My DRO is able to see all of the bits inside one of these
        calipers, not just the ones displayed. Very impressive accuracy given
        they cost less than $20. If you are interested, details are on my web
        site. I sure caught a lot of grief of some of my early claims. The
        attacks were a bit painful but I also learned a lot. There is also an
        article on how I tuned up my Electronic Edge Finder for max accuracy.
        It
        talks to my DRO to set zero which is handy.

        I never thought about building a touch pad because I assumed it would
        not be very accurate. Given what you have said so far, I will make one
        and see.

        Rick

        Glenn N wrote:
        > Rick,
        > The hot water tank gave up suddenly last night so it will be a day
        or so
        > before I get back to the shop, but I want to do some comparisons
        between
        > my
        > methods of using my home built touch pad, using my normal method of
        > touching
        > off the side on paper and trying to duplicate your results.
        > I don't think I have any end mills that have been sharpened other
        than on
        > the
        > end so they all seem to come out pretty close to specified diameter
        and
        > things seem to fall in under .002" off of what I am shooting for
        without a
        > lot of fussing. I use my touch pad on the sides and it seems to
        find the
        > high spot on the helix of the end mill very nicely. It is quicker
        to just
        > touch off on paper and go from there and I have not done any testing
        to
        > verify what the error margins are. Also I plan to investigate
        further
        > what
        > I see on my machine as the difference between a full width slot cut
        with a
        > 2
        > flute vs. 4 flute vs. cutter diameter.
        > So far the parts I have been turning out have amazed me with the
        accuracy
        > I
        > seem to be getting on final dimensions. I have only had the mill a
        couple
        > of years now and mine is the only mill I have experience on and it
        is
        > exceeding my expectations so it will be fun to see if I can add to
        you
        > database :)
        >
        > Glenn

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