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How difficult is it to cut threads on a lathe

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  • #46
    U.D. You may be correct about the humility, I however, have a problem with the SHOUTING, and think that there may have been gentler ways to make the point. Mike

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    • #47
      Someone once said:

      "There are no stupid questions - only stupid answers."

      When someone asks a question it is a quest for knowledge.

      When you never ask any questions you say to the world "I am too stupid to ask for help when I require it".

      Through the sharing of knowledge and understanding we all grow.

      A true, yet sad story:

      Sometimes when I answer questions I have been guilty of NRTFQ. When I first went to university I had a physics lab in which the point of the lab was to measure the acceleration due to gravity using a pendulum. Completed the lab - did the calculations, redid the calculations, got pissed off and programmed the computer to do the calculations...WTF is going on? OK, back pedal a little, more, more, crap. I know, RTFI! Oops. Oooooooops! Should have read the instructions! The swing of my dendulum was greatly in excess. Lab due tomorrow- what to do. Oh well, bite the bullet. Show all the work, all the confirmations, the printouts. My conclusion to the experiment was that excessive arc length and the failure to read the instructions had resulted in total failure in the experiment and I then proceeded to prove this conclusion. I handed in my work book. Two weeks later, the TA is handing the books back out stating the marks given for each. My lab partner got a stanine "1". Mine was last - he did not want to give it back. He said "Do you mind if I show the other TA's, Professors, and your advisor this?" I thought - oh crap, my goose is cooked! He continued "Well, I am anyway, this is exceptional - a '9'." I asked him what in hell he was talking about - I screwed it up. He said "Yes, you did. But you realized the source of error and proved it. Even doctorial students can finish their studies and never come to the revelation you did - it is the difference between a scientist and someone with a sheepskin."

      Moral: If you learn through failure - even a failure is a success.

      It may suck to admit you fail, drove 140MPH infront of a ghost car with radar, farted in an elevator, or completely buggered an expensive tool or part but, it is better to own it and learn from the experience than bury your head in the sand and hope it goes away - it will come back to haunt you.

      It is OK to be Human - nobudy is perfekt.

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      • #48
        Thrud, I am not sure what this is. Perhaps a rebuke? If so, you make the point better than I do. Correct with grace. Mike

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        • #49
          Philosophically (.. or is that "filosoficly"?) I'm in agreement with Mike. But after re-reading the sequence of postings I suspect Paul's intent was not as it appeared (ie. "shouting"). Granted (I guess) uppercase is interpreted in these forums as 'shouting'-I don't have a lot of experience in these electronic discussions. But I sometimes use uppercase simply to emphasize the word, not to be aggressive. For emphasis purposes Italics would be the most appropriate, but it's not handy here. Be that as it may, I wouldn't bother to offer a spelling correction that didn't amount to a hill of beans anyway... even if implicitly invited.
          Lynn (Huntsville, AL)

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          • #50
            Never tried cutting Ext. Thds with a tap, how would one do this? Thought I had seen quite a bit, now I am intrigued.
            CCBW, MAH

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            • #51
              The way I am familar with it is to use a broken tap. Grind the end square, leave two or three good teeth, and grind off the rest. You now have a two or three tooth thread chaser/form tool. Clamp in tool post parallel with work and cut threads as usual, except you can feed straight in. Leaves proper profile etc.
              Jim H.

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              • #52
                Re: external trheads with a tap. One of the "projects in metal" books (if I recall correctly) had a ball/concave ball cutting tool that used a worm gear. the worm gear was made using a 1/2-13 tap cutting on a blank disk held in place by the tool being constructed. The disk and tap were mounted just as they would be mounted when the tool was finished-except the tap was located where the worm drive gear would be in the finished tool.When the tap had "Hobbed?" the disk as far as you needed the gear to travel the tap was removed, a machine screw inserted and the worm was driven! It was a clever idea, dont know if it worked or not.

                Dave: My physics lab had only a few rules. One rule was: no erasing data. just a single line to show it was FELT to be erronous. Then a note to explain why the error was made. The Prof explained that some great stuff was discovered or explained from the error's and damn little from the experiement that proceeded as planned, especially if the results were as anticipated.
                Its the stuff we know (that aint so) that gets us into trouble.

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                • #53
                  Steve
                  Someone should have told that to Robert Millikin (sp?) when he fudged his data on the oil drop experiments to fit his "feelings" that it was correct. It turned out he was - but he did not prove it himself. The Noble prize was deserved for the original thought put into it but, I feel he "earned" it dishonourably.

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                  • #54
                    Scott,
                    You use it like a full thread form insert. John Stevenson uses the chaser head dies the same way - they are much tougher than a lousy tap! He even uses one for flat belt grooves (for auto fan belts). He is my kind of animal - Bodger Extremis!

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                    • #55
                      ave, it's my humble opinion that a lot of fudging goes on- especially today. I just don't believe a lot of the "modern" physics.
                      Too many assumptions built on assumptions that were made to explain data that was interpeted as meaning somehing that was preconceived.
                      But: an open mind catches few flys. Now what did I mean by that?
                      Steve

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                      • #56
                        Steve
                        I agree, few if any professors these days are passonate about their work - tenure being their prime concern it seems. A sad affair indeed. Too much politics and not enough "fun".

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