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  • #46
    Originally posted by Milacron of PM
    Ironic statement considering YOU are a major contributor to JT's "excess" talking/typing.

    Amazes me when that happens on forums....the original poster gets the answers he needs in the first two or three responses and it would end there. But then other folks keep chattering away, often with total irrelevant BS of speculation or that accuses the poster of this or that. So the poster continues on just to clarify matters or defend himself from the BS.

    And then the very BS perpetrator that contributed to the poster having to type unnecessarily more, is the very one who then makes fun of the poster for spending too much time typing about it !
    But not ironic of you to criticize those who don't agree with you or your butt kissin' cronies..... thats well known.

    Countless times you yourself have asked questions on your own PM forum and
    received good answers for the amount of info you provided but you bashed or belittled the poster because they don't have the ability to read your mind.

    Comment


    • #47
      Originally posted by J Tiers
      OK, they ARE out of spec.............

      Large end = 0.7148

      small end = 0.5764
      OK, now you are assigning dimensions to the taper. I find it difficult to measure tapers with common HSM equipment, and by your reply on the PM thread, apparently you do too;

      "Well, I simplified the measurement, to get a "close rough estimate", and found that if a taper is way out of spec, it won't fit well..... Kind of obvious, I guess....... "

      We have gone from an assumption to a "close rough estimate". However close and fourth place readings are kind of oxymoronic. It is extremely difficult to measure a taper, accurately locate the points where the two measurements were made, and then measure the distance between. What is the taper of the Bison center using this same "close rough estimate" method?

      I do find it more meaningful when actual information is presented rather than a rant because something does not meet with someone's approval.

      As far as the function of the tang on Morse Taper tooling, so far, I have three references that attest to the fact that it is used to drive the drill. The taper handles a portion and the tang a portion. I would be interested in seeing actual references that say it's use is only for removal, not opinions.
      Jim H.

      Comment


      • #48
        Originally posted by Evan
        The tang is for removal. It's not hardened
        I just put a morse taper in my Rockwell hardness tester, and the tang is hardened: 45 Rockwell C.

        I drove the penetrator into the flat on the tang immediately below the "MT3" label.
        "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

        Comment


        • #49
          It is extremely difficult to measure a taper, accurately locate the points where the two measurements were made, and then measure the distance between.
          It isn't difficult if you have one that fits properly to compare with. Reverse one to the other and tape together. Then measure across them. It should be the same measurement at both ends. Any difference can be attributed to the taper in question.

          I just made a MT2 taper last night and did it by using the compound. I had to shift it once since the travel isn't enough to do it in one setup. Finding the correct taper angle isn't hard at all nor is measuring it. Chuck up a good taper and use a dial indicator on the cross slide to touch off the taper at the ends, noting how far you have to wind the cross slide to get a touch. With a dial to measure the carriage travel between touches you are in a position to calculate the taper to parts per thousand, even with cheap equipment.

          BTW, the taper I made fits my SB tailstock with about 50% contact from one end to the other. That is pretty good for one that wasn't ground. It holds just fine too.

          As for the question of removal vs drive, I think it is pretty obvious. If the tang was intended as a drive it would be hardened. Also, if it is supposed to drive then why all the equipment without that facility, my lathe for instance? The tang is there to protect the spindle as well as for removal. The morse taper and other similar locking tapers are more than capable of providing the necessary drive when in good condition using parts that fit. It may seem necessary that the tang provide drive when using worn or poorly fitted parts but with decent quality machines and well made tooling it's clear that is not the case.

          I just put a morse taper in my Rockwell hardness tester, and the tang is hardened: 45 Rockwell C.
          I suppose mistakes do happen in manufacturing.
          Last edited by Evan; 02-10-2008, 09:25 AM.
          Free software for calculating bolt circles and similar: Click Here

          Comment


          • #50
            Originally posted by J.Ramsey
            Countless times you yourself have asked questions on your own PM forum and
            received good answers for the amount of info you provided but you bashed or belittled the poster because they don't have the ability to read your mind.
            Keep comments in the context of this thread here on this forum. Don't get so desperate for a "come back" that you are conjuring up BS about what happens on another forum.

            Comment


            • #51
              Here is what happens when a tool becomes worn and the tang is driving the bit.



              It's also not hardened. A single stroke of a file left the mark.



              The tool is Comet brand, made in England.
              Free software for calculating bolt circles and similar: Click Here

              Comment


              • #52
                Originally posted by Evan
                Originally posted by Lazlo
                I just put a morse taper in my Rockwell hardness tester, and the tang is hardened: 45 Rockwell C.

                I drove the penetrator into the flat on the tang immediately below the "MT3" label.
                I suppose mistakes do happen in manufacturing.
                Sigh. You're going to make me go out and get another one.
                "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

                Comment


                • #53
                  Yeah. Try a different brand. I was thinking the same thing but I don't have a hardness tester at home.
                  Free software for calculating bolt circles and similar: Click Here

                  Comment


                  • #54
                    Originally posted by Milacron of PM
                    Keep comments in the context of this thread here on this forum. Don't get so desperate for a "come back" that you are conjuring up BS about what happens on another forum.
                    You would do well to practice what you preach.............look in a mirror.

                    Comment


                    • #55
                      Originally posted by J.Ramsey
                      You would do well to practice what you preach.............look in a mirror.
                      Meaningless comment with a definite example to point to.

                      Comment


                      • #56
                        I want to say it was Frank Ford's site that showed a quick way to measure tapers. Just stand the arbor on a surface plate or other fairly flat surface. Take a 1-2-3 block and using the knife-edge portion of a caliper jaw, measure the taperered shank with the caliper laying flat on the 1-2-3 block with the block laying on its 1" dimension (1" up from the surface). Then flip the block to the 2" side and do it again. The difference is the taper per inch and can be converted as needed. For perhaps a better sampling, you could go from the 1" to 3" measurement if the length of the taper allows for it.

                        Nifty idea....but its not mine

                        Paul
                        Paul Carpenter
                        Mapleton, IL

                        Comment


                        • #57
                          Originally posted by JCHannum
                          OK, now you are assigning dimensions to the taper. I find it difficult to measure tapers with common HSM equipment, and by your reply on the PM thread, apparently you do too;

                          "Well, I simplified the measurement, to get a "close rough estimate", and found that if a taper is way out of spec, it won't fit well..... Kind of obvious, I guess....... "

                          We have gone from an assumption to a "close rough estimate". However close and fourth place readings are kind of oxymoronic. It is extremely difficult to measure a taper, accurately locate the points where the two measurements were made, and then measure the distance between. What is the taper of the Bison center using this same "close rough estimate" method?

                          I do find it more meaningful when actual information is presented rather than a rant because something does not meet with someone's approval.
                          JC, this has degenerated to basically a PERSONAL ATTACK on your part. Is there a reason for that?

                          I did not "ASSIGN" dimensions. I measured them.

                          And it does not matter a whit if it "meets with my approval" (imagine that said in a mincy-wincy falsetto). It is EITHER RIGHT or WRONG. it FITS or it DOES NOT fit. Your approval, or my approval, is irrelevant.

                          As far as a rant, my original comments were frankly "venting" about the silliness of having a beautiful, but wrong, part.

                          (You seem to be on a rant concerning me at the moment, if we wish to discuss rants....... We'll have this thread closed and deleted soon.)

                          NOT ONCE have I demanded Collis perfection for $1, but it WOULD be nice if the part were not COUNTERFEIT. If the part does not conform to the established definition of what it is stated and claimed to be, it is a COUNTERFEIT.

                          I bought the only offering of that vendor, (Victor Machinery, if you must know), and, ironically, would have happily paid several times more per part to get good parts. (you would have already known that if you had read what I said above)

                          So much for your assumption of me being a cheap B%$#@!d who wants it all for nothing.

                          Thanks for the compliment, though.

                          BTW, I only measured them to satisfy your curiosity, which you expressed so forcefully that you managed to get me interested in it as well. I already knew they had problems which made them unusable for me. "How much", is only a detail.

                          Anyhow, the taper has machined "edges" where the diameter reduces before the unfinished head starts or the tang begins. I measured the DIAMETERS AT THE EDGES, where there is a definite place for reference. And then the distance "along" the taper between those points. Some trigonometric exercises convert that to an axial distance, and deriving the taper is easy.

                          The edge gives a decent reference for getting the mic straight across, as well, rather than just guessing at 90 deg.

                          If anything, the taper would be UNDER-estimated by this method, since the "fat" end edge might have some rounding which would reduce its diameter and make it appear shallower. The error is all to the "steeper" side.

                          4 digits?

                          I read it off the mic and had no reason to ditch one or two digits. You'll note the length isn't to tenths......

                          In any case, the taper was measured as described, and found to be well out, out enough that fairly gross measurement errors would be needed to find it to be "good".

                          As far as measurement methods, Evan's method of measuring over two is good in some ways, bad in others.

                          1) it is pretty difficult to hold the two tapers straight and in contact at their max diameter. Any error in that goes right into the readings.

                          2) You need a "standard" to use as one of the units. Obviously if the parts you check are identical, whether with identical errors or both perfect, they will measure the same everywhere by similar triangles, and no information is obtained.
                          Therefore the accuracy is dependent on the "standard" taper used for comparison, and is questionable.

                          Anyhow, rather than some turkey with a bad T/S claiming the parts are crap..... we DO have parts which appear to be WELL out of tolerance.

                          If you can show how the measurement etc was worthless, I'm listening, but it appears to be good on a geometric basis.
                          4357 2773 5150 9120 9135 8645 1007 1190 2133 9120 5942

                          Keep eye on ball.
                          Hashim Khan

                          Everything not impossible is compulsory

                          "There's no pleasing these serpents"......Lewis Carroll

                          Comment


                          • #58
                            A little review of tapers and locking angles might be in order. Just to liven things up a little.

                            In design of machine elements, there is a "locking angle" which is determined by the coefficient of friction.



                            Here is a block on an inclined plane. The coefficient of friction for this particular pair of materials (plane and block) is F. To measure F, increase the angle of the plane until the block starts to slide. That angle is A. Then the coefficient of friction F is the ratio of the "normal" force N (that is, the force at right angles) pushing the block into the plane, to the "tangent" force T trying to slide the block along the plane. The load force L is the weight of the block (it should be pointing straight down - I didn't sketch it quite right). At angle A, the normal force pushing the block against the plane is N=LcosA, and the tangent force pushing the block downward along the plane is T=LsinA. The ratio of the two forces is the coefficient of friction - F=T/N=LsinA/LcosA=sinA/cosA=tanA. Very simple; that all follows directly from the definition of Coulomb or "dry" friction. Real life is complicated a bit by the fact that static or "starting" friction is usually a bit higher than dynamic or "sliding" friction, but both can be measured the same way - by measuring the angle A.

                            The angle A is also, not too surprisingly, the "locking angle." At angles less than the locking angle, a load L applied vertically can't push the block down the plane, no matter how large the load is. The friction force will always be enough to prevent movement. Angles greater than the locking angle don't lock. Any force L at all will cause the block to slide down the plane.

                            The concept of locking angle is vital in design of, say, gear trains. A tooth contact angle less than the locking angle will be a locking gear. A good example is a typical worm gear. Because of "locking" it won't transmit a torque backwards - a torque applied to the worm will move the gear easily, but a force applied to the gear will not turn the worm. The parts will break before the worm will be rotated by the gear. Exactly the same effect prevents bolts from spontaneously unscrewing themselves as soon as a load is applied. Similarly, most leadscrews are non-reversing - the load doesn't rotate the screw, no matter how great it is. By increasing the contact angle (done by increasing the helix angle of the thread or worm), this locking effect can be eliminated. A multi-thread or multi-lead leadscrew, or worm-gear worm, can be a reversing (that is, non-locking) mechanism. The idea, of course, is to use the geometry of the parts and interface - that is, the contact angle - to get the system to work the way desired. In some applications locking is good, in others it's not. The machine designer has to keep track of this.

                            This is all very simple geometry, but not as well understood as it should be. I've run into engineers who have never realized it.

                            Tapers can also be locking or non-locking. Non-locking tapers are fine for one of the uses of tapers - alignment of parts - but in practice the locking feature is usually beneficial, so most of the tapers we see are locking ones. R-8 has a non-locking taper, which is one reason why you'll never see it in a lathe tailstock. A locking taper won't permit movement under a torque load so long as it has an axial load sufficient to keep it locked. The situation is a bit different from the inclined plane described above, because on the inclined plane, the force trying to cause slippage, T, is always proportional to the applied load, L. This is not automatically the case with a taper. When drilling with, say, a tail stock, the axial force (the source of the locking force) is not always proportional to the torque on the drill. When drilling, yes, there is a positive axial force, and if the taper is steep enough (No. 2 Morse, say, vs. R-8) the taper will lock, and the drill bit will be held steady against the torque forces needed to do the drilling. But as soon as we start to back the drill out, we will have (relatively small) negative force - that is, tension instead of compression - on the taper, and it can no longer lock against the small torque caused by the drag of the bit on the sides of the newly-drilled hole. Then the drill bit (or chuck) will spin. The way to prevent this is to apply an external axial load sufficient to keep the taper locked - which is what a drawbar in a mill spindle does - or to bang the taper into place. Because of the elasticity of the steel (Young's modulus), banging the taper into place gives us an elastic force analogous to the normal force N or the load force L in the inclined-plane situation, and that in turn gives a tangent force T (depending on the taper angle, the coefficient of friction of the metals, and how hard the bang was) sufficient to take the place of the external load we don't have.

                            Interestingly enough, it is not strictly necessary that the taper fit well in order to lock. Note that in the inclined plane problem, the contact area doesn't appear in the formulas. A larger area does not give us more "friction force." For any given material, the more gradual the taper, the higher the radial force generated at the contact patch - whatever its size - when the taper is banged in. However, when the fit is poor, the alignment of the parts will also be poor, which means that the taper isn't doing its primary job.

                            Here is a Sharpie mark on a 2 Morse center. This center has been placed in a 2 Morse taper socket (not banged in!) and rotated slightly, thus scraping off some of the Sharpie ink. It's clear that contact is pretty decent over the length of the socket (which is shorter than the center, so the ends of the center didn't make contact at all, and the Sharpie line there is undisturbed).



                            Here is the same center placed in a 7 Brown & Sharpe socket. The tapers are very similar, but that's not close enough. Only a narrow ring has any contact at all. If banged in, this combination could be expected to resist torque as well as the proper 2 Morse center and socket, but the alignment of the center in the B&S socket will not be good.

                            Comment


                            • #59
                              Originally posted by J Tiers
                              So much for your assumption of me being a cheap B%$#@!d who wants it all for nothing.
                              Nothing wrong with cheap. None of us have infinite resources. Besides, as a new England skinflint of frugal Scots antecedents, I pride myself on my traditional "respect" for money.

                              Comment


                              • #60
                                Thank you.

                                I DO often find that more cost is sometimes cheaper overall..... Although I AM disinclined to spend extra.... (Swedes)

                                Great explanation of tapers.

                                One thing......

                                The "holding" of an improper taper against pulling out is somewhat dependent on the "stiction" factor. It's harder to start it slipping than to keep it going once started.

                                BUT, if the thing WOBBLES, due to the improper taper allowing movement, then the "stiction" is broken, and you have ordinary sliding friction.

                                That's why what is implied by the area not appearing isn't as true in reality as it is in theory.

                                But I totally agree with your statements. They agree with my intro to M.E. distribution courses.... Thanks for the reminder!
                                4357 2773 5150 9120 9135 8645 1007 1190 2133 9120 5942

                                Keep eye on ball.
                                Hashim Khan

                                Everything not impossible is compulsory

                                "There's no pleasing these serpents"......Lewis Carroll

                                Comment

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