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  • Trammalamaringthing

    Sorry about that title. (not really) Here's a couple pics of the 'ring thing' I'm using now to run the indicator on while tramming the mill.




    Pretty self-explanatory. First pic is one way, other one is upside down. This is a part out of an automatic tranny. Notice the polish on the 'teeth'- I worked this part around on some sandpaper on the surface plate and found that these teeth are 'high', so it worked out that once sanded it sits very flatly on the mill table. In the first pic you can see the result of my milling the outside 1/4 inch or so to make it perfectly flat and smooth. This is the area where the indicator needle rides.

    The boss sticking up in the center makes it easy to center under the spindle by eye, especially if there's an mt3 adapter of some kind mounted in the spindle. That boss will probably get in the way if there's some other tooling mounted, but I'll deal with that if and when the time comes. As it is, I can mount and unmount the indicator to the spindle without removing any of the endmill holders I normally use. Not that it really matters- on this mill tramming isn't something you do every day or every week.

    I get a little obsessed now and then, so lately it's been this whole mill alignment thing. In that vein, I've also wondered how well the table will measure up as I move it to extremes in both axis. It has occurred to me that all I know at this point is that the spindle to table distance is equal all around a 5 inch circle with the table centered. I'm going downstairs now and crank the table around and take measurements again. Back in a while.
    I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

  • #2
    Ok, well that was interesting. I've got a whole foot or so lengthwise where the table is good, then it drops by a thou at one extreme and by two thou at the other extreme. That's with the gibs snug. Across the width it's perfect. At least now I know the 'envelope' for close results.

    From all the reading I did last night (and this morning) I now have one more thing to check- leveling the bed. Heh, I don't think that's been talked about here, leveling the mill-
    I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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    • #3
      Watching this with interest.
      I have an X2 mill that I'm trying to tram at the moment and anything that makes the task easier is very welcome.
      Regards
      Geoff
      My place.

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      • #4
        That's quite similar to my method:

        http://www.youtube.com/watch?v=ZfioLDhBNBQ

        Because the rotor is quite a large diameter the fake Blake coaxial indicator is rather sensitive to variations. This works quite well, in fact. Brake rotors are machined to a very high degree of parallelism between the adjacent braking surfaces.

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        • #5
          Originally posted by tumutbound
          Watching this with interest.
          I have an X2 mill that I'm trying to tram at the moment and anything that makes the task easier is very welcome.
          Geoff,

          It looks like we have the same mill (the red X2 - I hear they are much better than the other colors). This document has some good advice about adjustments, including tramming. I'm still way new at this, but I've trammed it a few times with pretty good success using a dial indicator and a plastic hammer. Perhaps we can trade tips?

          -Pete
          I just like to make stuff.

          Comment


          • #6
            Pete,
            I agree, the red ones are the best! Actually, that's the only colour they come in here.

            I've been able to get the X axis sorted out pretty well. Within about .02mm over a 150mm distance from center.
            It's the Y axis that's proving difficult. It seems to be a bit trial and error in getting the correct size shim in the right place under the column mount.
            Running the DTI across the t-slots is a bit of a concern so something like darryl's solution (or a brake rotor) would be a help. Someone had suggested a big bearing race which I'll try to find.
            Regards
            Geoff
            My place.

            Comment


            • #7
              Am I missing something here? After you milled the outside 1/4 inch how did you know that the plane of that surface was parallel to the plane of the underside/table surface and to what precision.

              Phil

              Originally posted by darryl
              In the first pic you can see the result of my milling the outside 1/4 inch or so to make it perfectly flat and smooth. This is the area where the indicator needle rides.

              Comment


              • #8
                (sorry to hijack this thread, just a quick reply)

                Geoff, you are waaaaay beyond me. I've only done the x-axis. But now you've got me thinking about the tiny little step I get between passes when facing. Barely noticeable, more of a slight imperfection really, and it hasn't concerned me so far, but now it is going to bug me, knowing I can potentially do something about it.

                I'll have to look into y-axis tramming after I finish my current project. Good thing I have a 1.5 week vacation starting tomorrow eve .

                -Pete
                I just like to make stuff.

                Comment


                • #9
                  Nice to tram things in perfect, but on HSM grade machines... What does your perfect tram look like under working conditions ? say .050 in DOC on Rockwell C 42 in 4140?

                  Everything flexes, my 5500 lb mill with a 12 in square of 4140 flexes..

                  Work to the level you need.. Any more is just wasted time

                  Most HSM machines can do HSM+ grade... But every machinist has got to know his machines limitations ...

                  Working with a even slightly swaybacked lathe or mill... nothing is perfect...

                  Hmm I have some Cat D9 Transmission gears around ~26 in OD I could set on mill table... But still overkill for a mere Bridgeport, or even a Cinci 2MI..
                  Last edited by Bguns; 12-23-2009, 04:38 AM.

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                  • #10
                    Phil, what I did was lay this thing in the center of the table, then clamp two pieces of bar to the table to create a V that I could slide the ring up to. That let me rotate the ring by hand while it stayed in a general position. I then cranked the table to bring the edge of the ring up to the cutter. Got my cutter height just right to skim off a thou, then carefully cranked the table over to take a skim cut about an eighth wide. I used a new edge on the insert and carefully slid the ring to nest up to the bars, then slowly spun it while keeping it in full contact with the mill table. Once I got all the way around, I cranked the table over a bit more and got the machined area wider. Once I had it about a quarter inch wide, I dropped the cutter another thou and did it all again. Once I had a good width machined with fresh cut metal over the whole width, I put in three more full turns of the ring while the cutter swept off any high spots.

                    Note that I was turning the workpiece by hand, against the cutter rotation, keeping it moving slowly but surely and never letting it lift off the table. The one thou depth of cut with the fresh cutting edge was easy enough to rotate the ring into, but at the first feeling of weakness in my hands, I'd slide the ring away from the cutter and rest my fingers. Cutting that circular land that way took maybe fifteen minutes.

                    After that I took a file and while allowing the land to control the file to be flat on it, I went around a few times to even out the high spots. I alternated directions as well. Some steel wool after that to remove a bit more of the roughness, and then it got rotated under the indicator mounted to the spindle to test. I could see the needle quivering a bit as I rotated the ring underneath it, but it never moved off the mark. My estimation is that the height of that circular land doesn't vary more than a tenth or two all the way around.

                    I also slid the ring side to side so the indicator touched across the width of the land, just to make sure it would read consistently. The ring doesn't have to be perfectly centered under the spindle in order to work properly.

                    I know I've prated on a bit with the explanation of this procedure, but in part I'm trying to put forth the idea that because the table isn't moved except very slightly, the distance from the cutter to the table will not be varying at all, and anything which is trimmed in that same spot is going to come out at exactly the same length, or in this case, the machined circular land is exactly parallel to the table at any point. I turned the ring around three times taking spring cuts, to the point where all I was getting all around was bits of dust here and there coming off. Because this was the last of the machining done on the land, any change in the relative position of the cutting edge due to heating of the spindle etc, would have been stabilized. That's important to note.

                    Something else to add- I have, or had, a large bearing race that I used to use for this. If you do that, check that the printing on the edges isn't going to interfere with your readings. I found that discrepancy by accident, as I had not considered that before.

                    Last note- I had a tilt and a nod error with my column, which means it was leaning sort of left-rear. I thought that might be complicated to shim, but it's as easy as pie. Do a left/right shimming first, using equal thickness shims front and back on only one side until you get no discrepancy, then go equal thickness shims again, but on the left and right sides- front or back as needed to lean the tower the proper direction. For either direction of tilt, using equal thicknesses of shim will prevent the other direction of tilt from being affected. That's the key to it. Of course, I'm assuming a four bolt mounting pattern for the column, four corners where you could potentially shim. Be aware of course that you'll only need shims under three corners when you're done-

                    Bguns, everything flexes, that's for sure. Without much force applied as well, as I'm finding out. If I took that strenuous of a cut as you've described on my wet noodle mill, the tram would be way off during the cut. Hopefully though, once it comes down to a spring pass as a final, the surface would not have any cupping or ridges left on it. One thing I have seen is when I take a heavy cut, but come too close to the final dimension, then the finish cuts level off the high spots and leave gullies behind where the cutter got in too low during the heavy cut. Operator error, of course.
                    Last edited by darryl; 12-23-2009, 05:31 AM.
                    I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

                    Comment


                    • #11
                      Round-a-bout?

                      Originally posted by tumutbound
                      Pete,
                      I agree, the red ones are the best! Actually, that's the only colour they come in here.

                      I've been able to get the X axis sorted out pretty well. Within about .02mm over a 150mm distance from center.
                      It's the Y axis that's proving difficult. It seems to be a bit trial and error in getting the correct size shim in the right place under the column mount.
                      Running the DTI across the t-slots is a bit of a concern so something like darryl's solution (or a brake rotor) would be a help. Someone had suggested a big bearing race which I'll try to find.
                      Geoff.

                      Have your Dial Test Indicator laid back with its axis to be both about 30 > 45 to the table and tangent to the arc/circle you are tramming - the stylus should be the trailer and the dial end the leader. That way there will be less load on the stylus and its supports and the load on the stylus will be all vertical with no lateral load on it to strain the stylus bearings.

                      This way the stylus will slip over the tee-slots and not crash into them.



                      A bearing race or a "flat" like a brake disc as shown should be OK - but in that case run Carpenters red/grey fine/coarse oil stone over your table to remove any burrs or "dings" as that can stuff up an otherwise good set-down of the ring/disc onto the table. The oil-stone I use is in this pic. ("Bunnings" and others in OZ have them):

                      Comment


                      • #12
                        I'm sure it's been linked to before, but have a look at this shop made copy of a quick tramming tool.

                        http://madmodder.net/index.php?topic=822.0

                        Paul Compton
                        www.morini-mania.co.uk
                        http://www.youtube.com/user/EVguru

                        Comment


                        • #13
                          Darryl your method of cutting the junk trans part is not only inaccurate, it's dangerous as hell. Don't EVER cut anything that is not well secured to the machine. Yeah I know you were only taking off a thou and when you bump something inadvertently you may take off a hand.
                          Something this forum and it's associated magazines lack is any emphasis on safety. It is disgraceful to publish some of the dangerous crap that they do. I would be amazed if they are able to buy liability insurance.
                          dp as far as brake discs ( not rotors) being a high level of precision, dream on. Yes they should be. No they likely are not. And if you don't know for certain then you are pissing in the wind.
                          It is not necessary to reinvent the wheel here. Put the indicator in the spindle and indicate the TABLE. not a piece of junk of unknown and unlikely parallelism .
                          Last edited by tdmidget; 12-23-2009, 08:59 AM.

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                          • #14
                            Why are some folks reluctant to tram off the table?

                            Anything you put between the table and the DTI is going to throw your measurements off.

                            Just make sure the indicator probe is pointing away from the direction you're sweeping.
                            "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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                            • #15
                              A large, in this case 10", bearing race is the bomb for tramminization!


                              Rex

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