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  • Tramming tool

    I made a tramming tool

    The way I made it was to drill the holes for the indicators and then the hole for the shaft mid way between the other two holes. I pressed in with loctite a shaft in the center hole, chucked it in the lathe and faced off the base so that it would be perpendicular to the spindle. I put an indicator on it while still in the lathe and it was dead nuts spot on.
    I assembled it and zeroed out the indicators and mounted it in a collet in the mill and trammed the mill with it. Everything was in order but the first set of test cuts came out horrible. Long ridges told me that the mill wasn't trammed properly so I zeroed out the tool again and double checked the plumb of the spindle. It read right on but when I rotated the tool 180 degrees it was around .010" off. What the heck is up with this?

  • #2
    Just a novice thinking out loud here but maybe it's the drill chuck? I would try it in a collet.

    EDIT: Nevermind, I see now you did use a collet. Sorry.

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    • #3
      Only collets were used in the making.

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      • #4
        Originally posted by Kd0afk View Post
        ......

        I assembled it and zeroed out the indicators and mounted it in a collet in the mill and trammed the mill with it. Everything was in order but the first set of test cuts came out horrible. Long ridges told me that the mill wasn't trammed properly so I zeroed out the tool again and double checked the plumb of the spindle. It read right on but when I rotated the tool 180 degrees it was around .010" off. What the heck is up with this?
        How are you zeroing out the indicators? Do you have a a plane surface that you know to be exactly perpendicular to the spindle? That would seem essential.

        Maybe adjust the tram .005" in the other direction, make a trial cut, and if good re-zero against that surface.
        You're probably seeing an accumulation of errors. ...that's my guess.
        Lynn (Huntsville, AL)

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        • #5
          The tool is zeroed out by sitting it on a flat surface. I have a granite plate for that. The shaft indicated to be perpendicular to the base.

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          • #6
            This reminds me of the guy who once asked me to borrow my level, to check his! I asked him how he knew mine was accurate and his was not? Of course a level is easy to check. Set it on a roughly level surface and observe the reading. Flip it 180 degrees and if it is in calibration it will read exactly the same.

            I have seen these tramming devices and thought WTF? When you use two indicators like this you have introduced whatever error the two indicators may have, and whatever error the spindle, and collet may have. So in order to properly calibrate this device you need to swing it in a properly trammed spindle with the first indicator and zero it. Then you need to swing the second indicator and adjust it also to read exactly zero. As long as you leave it in the spindle it will be accurate. Take it out and all bets are off. There is a good reason that a single indicator is the most accurate way to tram a spindle.

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            • #7
              Originally posted by Kd0afk View Post
              The tool is zeroed out by sitting it on a flat surface. I have a granite plate for that. The shaft indicated to be perpendicular to the base.
              Well, apparently something went awry. Either the "flat" surface isn't (maybe some dust), or the shaft isn't quite perpendicular.

              Another possibility of course, is the assembly is somehow cocked in the collet so that the plane traced or swept by the two indicator tips is not perpendicular to the axis of rotation.
              Lynn (Huntsville, AL)

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              • #8
                I will make a video and try and post it to explain what's going on.

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                • #9
                  I know how to check a level for accuracy and how to check and adjust a tri square for squareness, that is not the issue.

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                  • #10
                    All you have to do to zero it is put it in the spindle (preferably in a collet), zero 1 indicator, turn it 180 degrees and zero the other indicator. This way you are zeroing the indicators both on the same spot on the table, perpendicular to the spindle. Make sure the spindle is locked so it can't go up and down.
                    Last edited by Toolguy; 02-15-2015, 01:58 PM.
                    Kansas City area

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                    • #11
                      As a secondary test chuck it up in your lathe's tailstock and see if your stationary chuck face is square at each 90؛ point of rotation of the tool in the tail stock.

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                      • #12
                        I'll try what's suggested.

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                        • #13
                          Yes. I made one of these devices as well, beautiful little helpers.

                          But the easiest way to use them is like this...

                          It helps to use a 1-2-3 block, thick parallel, gage block, small surface plate, some such - a good, flat surface, laid on the mill table.

                          Raise the table / lower the head so that one indicator touches the surface. Zero it. Preferably just touch it, without going more than a quarter-revolution, so as not to have to worry about how many revolutions and such.

                          Turn the tool 180 degrees, without moving the knee/head at all, and zero the other indicator on the same surface. Again, preferably without going more than one revolution, that cuts down on confusion...

                          You can then bring the tool down/table up to where they touch the table. See the differences, and adjust as needed.

                          Front-to-back (Y axis) tramming can get a bit confusing, as both indicators will move the same amount - just at different rates, until they finally do match.

                          Good work!

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                          • #14
                            Zeroing each indicator on the same point by rotating 180 degrees worked. Thanks guys

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                            • #15
                              Personally I think one of those devices is a waste of time and money. If you read the directions for one of the professionally made ones they tell you to zero the unit simply by setting it on a "flat" surface. This works if the centrelines of the mounting shaft and the two indicators are all perfectly perpendicular to the base and parallel to each other--somehow or other yours aren't.

                              The easiest way to tram a mill table is to use a good back plunger DTI with a large (1/2" or greater) button point. Set it so the plunger just kisses the top of the table and it will glide over the slots no problem. This also allows you to swing the tool through a larger radius which will give you a more accurate tram...
                              Keith
                              __________________________
                              Just one project too many--that's what finally got him...

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