Announcement

Collapse
No announcement yet.

Impressive $20 brake rotor for tramming the mill

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • #16
    Originally posted by A.K. Boomer
    I respectfully disagree --- I have my vise AND RT table bolted to the mills table most of the time, They both are very stable and tested to good precision - I only do the mills table and then everything else is as good as it gets and by far good enough for 99%, If it wasnt it would be stoned in to be good as I need, or I might re-tram for a very very special occasion.
    I dont have time to go tramming everytime I switch from vise to RT table and such as sometimes this would require 5 trams in a couple hours --- since compound errors would have the chance of increasing if say I trammed to the RT table and then used the vise without tramming (I.E. two segregated pieces attached to a common) then the only real logical solution is to eliminate a compound and start with the common (the table) since I already know the deviances (or lack there of) of both my RT table - its taper mounted three jaw and my Kurt vise I make the assumption that i can pretty much count on everything being within a pre-determined range --- So far - so good

    If your really having that much deviation from RT table to vise ect. enough to have to re-tram every time then I would check into better quality bolt ons or bring them around somehow - or stop working on space shuttle stuff in your home shop
    Cummalitve error is but a small concern,the mill going out of tram while in use eclipses it.Bridgeports and their related kin are as rigid as wet noodles.It is very much possible for a two flute 3/4" endmill to chatter a BP head out of tram.

    Putting a cheater pipe on the wrench when tightening the tie bolts won't solve that either.
    I just need one more tool,just one!

    Comment


    • #17
      Originally posted by nheng
      Speaking of tramming to the vise, I got quite the surprise a few days ago when I put a seldom used Grizzly 5" mill vise into use on the BPT. The jaws are parallel to the table to within 0.001" but the "slides" (if that's what they're called) have a whopping 0.008" across the vise width. Bummer ... it looked precise
      Had the same issue with my 5" Grizz vice.It was out .002,until a removed the swivel base.With that gone it's within .0003 over the width which is fine.The base will get hit with the rotary surface grinder to see if it improves.
      I just need one more tool,just one!

      Comment


      • #18
        Originally posted by lazlo
        Yeah, I don't know why folks go through hoops with 1-2-3 blocks, tram rings, TramARounds, ... I'm guessing they see those T-slot and assume it's going to crash their Tesa DTI



        Judging by the circular grind marks, I'd have guessed that they're Blanchard ground, one side at a time.
        A chunk of plate glass or a tram ring makes life quicker and easier and the machine can be trammed with the spindle spinning that's all.Some of us have to make a living doing this

        They still do both faces at the same time,if the thickness of the surface varies .003-5" you feel it in the pedal.Some argue the blanchard marks make the breakin time go faster.I never saw any diffrence between turned or ground.
        I just need one more tool,just one!

        Comment


        • #19
          I know what AK means, but at school I tram the head to whatever I'm working on every time I use it. I am very suspicious of those machines, since they are often crashed or abused before I get there. There is never any guarentee that the vice is square/parellel to table travel or that the head is trammed to the vice (or table or index or whatever happens to be neccessary)

          Comment


          • #20
            Originally posted by wierdscience
            A chunk of plate glass or a tram ring makes life quicker and easier and the machine can be trammed with the spindle spinning that's all.Some of us have to make a living doing this
            Point taken. I do this for a hobby, so I can spend all the time I want tramming the head

            On the other hand, if you haven't mounted a vise or rotab, it's just as fast to sweep the table as to put a tram ring on the table and sweep it...
            "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

            Comment


            • #21
              Originally posted by lazlo
              On the other hand, if you haven't mounted a vise or rotab, it's just as fast to sweep the table as to put a tram ring on the table and sweep it...
              You'd have to be mighty fast to do it at 400rpm
              I just need one more tool,just one!

              Comment


              • #22
                Originally posted by wierdscience
                You'd have to be mighty fast to do it at 400rpm
                I'm going to have to call you on that one Wierd. Why the need for tramming the head with the spindle running? I'm a hobby guy, and I tram my mill head maybe once a month.

                Are you actually tramming your mill head several times during a milling operation? Why???
                "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

                Comment


                • #23
                  Originally posted by lazlo
                  I'm going to have to call you on that one Wierd. Why the need for tramming the head with the spindle running? I'm a hobby guy, and I tram my mill head maybe once a month.

                  Are you actually tramming your mill head several times during a milling operation? Why???
                  No,I tram with a coaxial indicator with the spindle running and up to operating temps.Doing it this way all runouts average out and things don't change just because the spindle warms up.

                  You can also map out the quill travel error and the knee travel error using this method.
                  I just need one more tool,just one!

                  Comment


                  • #24
                    Originally posted by wierdscience
                    No,I tram with a coaxial indicator with the spindle running and up to operating temps.Doing it this way all runouts average out and things don't change just because the spindle warms up.

                    You can also map out the quill travel error and the knee travel error using this method.
                    Ah, that's interesting Wierd -- I'll have to try that. I have one of those Chicom Blake clones, but I've only used it to indicate a rotab or a circular workpiece.
                    "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

                    Comment


                    • #25
                      Blending

                      I've heard it all with regard to "tramming" the vertical milling spindle to the milling table.

                      So let's take that as a "given" irrespective of what method/s you use or don't use.

                      When was the last time you checked your mill table for parallel to your "X" and "Y" ways? Or that your "X" and "Y" ways are accurately at 90 degrees to each other. Or that your table top is accurately at 90 degrees to your "knee" vertical ways (dove-tail or square/flat?).

                      If your knee has "sagged" say 0.10 degree (6 arc minutes) and you tram your spindle to your table it will be fine and you will get a nice even over-lapped "circle/arc" pattern on your job.

                      (arctan 0.1 arc minute = 0.0017 = 0.0017 per inch = 0.0140" per 8").

                      So if you trammed your spindle over 8" and then moved the table 8" in the "Y" direction you would still be trammed correctly. But two cuts 6" apart using "X" using a fly-cutter set to 8" would have a significant "step" of (0.0017 x 6 = 0.0140") - or there-abouts - instead of the smooth over-lapping "blended" cut you may have expected (or been hoping for??).

                      Ever wondered about that "unexplained" "saw-tooth" effect you have been getting between parallel cuts (usually in the "X" direction) when your "tram" has been "perfect"/"dead nuts"/"spot-on"?

                      I only used the "0.1 arc degree" as an example but it is quite possible that similar smaller errors exist that no amount of "tramming" will detect.

                      I will/may address vices later.

                      Comment


                      • #26
                        You may be an oldtiffie but you are a wisetiffie I hear the sound of many feet running to get their angle plates.

                        BPT built in +0.0005" measured at the front of the knee. Probably to compensate for droop with a nominal load rather than wear.

                        I look forward to your vise discussion. Maybe a Kurt will find its way home before that and I can send the Grizz back to the docks or have a friend grind it.

                        Comment


                        • #27
                          Originally posted by oldtiffie
                          If your knee has "sagged" say 0.10 degree (6 arc minutes) and ... you trammed your spindle over 8" and then moved the table 8" in the "Y" direction you would still be trammed correctly. But two cuts 6" apart using "X" using a fly-cutter set to 8" would have a significant "step" of (0.0017 x 6 = 0.0140") - or there-abouts - instead of the smooth over-lapping "blended" cut you may have expected (or been hoping for??).
                          Sure, I think we all know that Tiff. If you're running a clapped-out machine, you'll have to compensate for it (or rescrape the back of the knee).
                          But that is off-topic from the OP. Putting a disc brake or a TramARound on top of a sagging knee isn't going to fix anything.

                          Same deal with the vise: you can tram on a parallel in the vise, but if the table's really worn like you describe, you'll have the same problem the moment you move the table.
                          "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

                          Comment


                          • #28
                            Wait and see.

                            Nope - not OT as regards the OP - at all.

                            Originally posted by lazlo
                            Sure, I think we all know that Tiff. If you're running a clapped-out machine, you'll have to compensate for it (or rescrape the back of the knee)
                            I don't think that you are in a position (again!!) of speaking for the collective "all" (of us?) nor individual member (n)or reader of this topic or forum.

                            If that is your own individual opinion - that's fine - as I respect that.

                            I don't recall saying that the machine was "clapped out" either, nor by infernence, or extension, that it needed to be re-scraped.

                            This situation also applies to "mill-drills" (which have no "knees").

                            Wait and see how things develop before you pre-judge other peoples interests and responses - or lack of them.

                            But that is off-topic from the OP. Putting a disc brake or a TramARound on top of a sagging knee isn't going to fix anything.
                            It is not OT as it relates directly to some of the problems that may be over-looked as errors develop that may have been assumes would be corrected by "tramming".

                            As using any sort of suitable disc or flat/parallel plate is a viable option for tramming as used by some other than perhaps yourself, it is definitely not OT.

                            I just checked the OP and a disk brake is in the OP on my computer. It is:
                            Originally posted by nheng
                            Although I have a garage full of old brake rotors, I hate to machine CI in the shop. Stopped at Autozone this evening and had the girl grab any small (thin) rotor off the shelf. She looked up the price and it was $20. I forget what car it was for but here are some very careful measurements ... quite impressive.

                            Rotor thickness variation measured at 4 quadrants, at 2 diameters:

                            +/- 0.00005"

                            Height from outer face (at wheel hole pattern) to rotor surface (also 4 quadrants):

                            +/- 0.0001"

                            In short, these Chinese rotors are on a par with the best quality parallels !

                            Of course, they are soft and they have a fine turned, not ground finish and these accuracies are only possible because the faces of the mics ride on (and integrate) the surface peaks.

                            Still darned good for $20 and it let me tram the mill within 0.0005" across about 8" in 5 minutes. A large diameter ball or roller contact point would allow the DTI to see close to the accuracies listed above.

                            Den
                            Same deal with the vise: you can tram on a parallel in the vise, but if the table's really worn like you describe, you'll have the same problem the moment you move the table.
                            There you go - pre-judging again - without even having seen it (yet).

                            I do hope you are not adopting an intimidatory approach toward nor "talking down" to me here - as if so, I can assure you that it will not work.

                            So, just wait and see what transpires.

                            Comment


                            • #29
                              Originally posted by oldtiffie
                              I don't think that you are in a position (again!!) of speaking for the collective "all" (of us?) nor individual member (n)or reader of this topic or forum.
                              I said "we all know that" because you posted something so ridiculously obvious, that anyone who wasn't asleep would realize it: that tramming only works if your table, knee, and column ways aren't worn.

                              We get it Tiff, and it's off-topic from Den's original post, which was using a disc rotor for tramming purposes.
                              "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

                              Comment


                              • #30
                                Originally posted by wierdscience
                                Cummalitve error is but a small concern,the mill going out of tram while in use eclipses it.Bridgeports and their related kin are as rigid as wet noodles.It is very much possible for a two flute 3/4" endmill to chatter a BP head out of tram.

                                Putting a cheater pipe on the wrench when tightening the tie bolts won't solve that either.
                                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?

                                Comment

                                Working...
                                X