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  • OOPS so close but the cigar is toast

    Some of you may recall the indexing table I was making out of pvc. Well, today I finally got around to marking it out in pencil as a double check before doing the actual scratching of degree marks. Counted off five degrees, mark- another five, mark- another five, mark- Coming around, 340 degrees, 345, 350, 355, 359/0 - oops

    Turns out all the double checking I did was for naught- I have only 359 divisions instead of 360.

    I'm trying to remain calm. I don't know if I should try to raise my blood pressure or lower it. Should I go eat another big meal, or try to bring up what I last ate. Put a brick through the tv screen- maybe now's the time to clean the carbon out of the van's engine- maybe I should just sit back and ponder the pleasures of needlepoint-

    $%$^%#^p()(&(_*&%$^$%w$)(*%o%*&@^w^%%!

    Well, that didn't help much. Sigh.

    It will be quite a bit of work to fix it, but it can be done. I'm going to see how well epoxy sticks to pvc, since I'll have to rip out the beautifully made threaded rod loop, and the indexing section, since that will no longer fit perfectly to the new loop. I will have to make a new loop since I'm not going to be able to get the epoxy out of all the threads so I can re-glue it with one more space.

    This is not what I wanted to find out- it is an error and it is a big one for this project. What probably happened was that I counted the threads starting from 1, and ended with the 360 in the same thread, when it should have been 360 ending in the 0 position.

    Obviously I'm human. I need a drink.
    I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

  • #2
    Know how you feel Darryl. Last night I finished putting together the last of the 14 drawers for the tool cabinet in the garage. Built the cabinet with a workbench top to replace the Craftsman roll around that I never roll around. Anyway, mounted the full extension drawer slides to a drawer and go to slide it into place, ARRGH, it a tight fit, too tight. After all of my careful measuring and calculating the inch plus of room is about an eighth of an inch short of what is needed. To say the least, I was not a happy camper. At least, it's woodwork and it can be salvaged, but I'm still p****d at myself for not doing a test fit after the first drawer was built.

    I was watching your rotary table project and I've got the allthread idea stored away for future use. Hope you can salvage the nice work you've already put into it.

    Glenn
    So many projects . . . so little ambition! Arroyo Grande, CA

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    • #3
      Shame

      That really is a shame as it was/is a superb job Darryl.

      Yep - always start at zero.

      It is surprising how prevalent that problem is.

      The end of a rule is at zero - the 1" mark is 1" further on.

      Try convincing some people that a baby less that 1 year old is in its first year - which is true. The clock starts ticking at "zero hour" - when the baby is born.

      Its first birthday is the first anniversary of its birth.

      On my 21st. birthday, I had been alive for 21 years and was just commencing my 22nd. year.

      On my 60th. birthday I had been alive (from when I was born 60 years ago on zero time) for 60 years, was entering my 61st.year and my 7th. decade.

      See how many people will get it wrong if you ask them to count the teeth on a gear with a large number of teeth.

      Anyway, I really do hope that you are able to recover and restore it.

      Comment


      • #4
        [never mind, probably not relevant]

        Comment


        • #5
          Darryl, while upsetting, these are growing and learning experiances. That notion, along with "need is the mother of invention" will likely propel you to a better answer. My guess is you and your project will come out of this better than you went into it. It's all in what you choose to make of it. Anyone to pull off a project as slick as yours is sure to finish up front in the pack.
          - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
          Thank you to our families of soldiers, many of whom have given so much more then the rest of us for the Freedom we enjoy.

          It is true, there is nothing free about freedom, don't be so quick to give it away.

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          • #6
            Yep - always start at zero.

            It is surprising how prevalent that problem is.
            We computer geeks call that an 'off-by-one' error and it's probably the biggest re-occurring programming error.

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            • #7
              Darryl,
              Sorry fot that , wish saying we all have done similiar and likeley will do again would help but I know it wont, wouldn't help me either!

              Any way, maybe some forum sympthoy post and the time it takes to read them may help calm down that temptation to kill your TV.

              Kenny

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              • #8
                I'm absolutely heartbroken at your loss Darryl, but I sure enjoyed the way you wrote it up! That was good for a big laugh. I'm sure we've all felt those emotions at one time or another and you described them very well.

                Hard to lose a piece you've invested a lot of time in tho. Now that I've stopped laughing you have my condolences and a sincere wish for success on the rework.

                SP

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                • #9
                  We computer geeks call that an 'off-by-one' error and it's probably the biggest re-occurring programming error.
                  Yep, except I have always heard it called a "fence post error". Example, how many fence posts does it take to make a fence with 10 spans of wire?
                  Free software for calculating bolt circles and similar: Click Here

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                  • #10
                    HEY, I am surprized no one has pointed this out! Leave it alone, do not try to fix it, it is not worth the effort. You are only off one degree in 360 degrees. that is only an error of 10 seconds per degree. You can not read the protractor that close. On most things it is just not going to matter. Or am I wrong? Gary P. Hansen
                    In memory of Marine Engineer Paul Miller who gave his life for his country 7-19-2010 Helmand Province, Afghanistan. Freedom is not free, it is paid for with blood.

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                    • #11
                      Sorry to hjear of your dissapointment son keep up the otherwise very good work kindest regards Alistair
                      Please excuse my typing as I have a form of parkinsons disease

                      Comment


                      • #12
                        Uh, what is it- nine fence posts- yeah that's it- (or is it twelve)

                        Thanks for the encouraging words. I will be able to salvage it- I stayed up a bit last nite to see if I could pry the epoxied rod out of the groove without damaging the table, and it wasn't that hard. Pvc doesn't grab onto epoxy well enough to be a problem- unless you need it to hold something- . In my case it's mostly a filler in a groove, so it does the job well enough, and I was able to remove it without problem. I curved up a new rod and cut it to length before I retired last night (this morning) and it will work out fine.

                        I had a similar problem with some drawer slides I installed- final dimensions were off by about 1/16, and I'm using them but it's tight. It eats at me a bit each time I open a drawer. Talking about that 1/16- I bought a tape measure the other day and remembered the experience I had with one being short by that sixteenth. I went through about 6 or 8 tapes before I found one that read properly. It was the cheapest one there too, so now I'm the proud owner of a piece of crap that measures correctly.

                        It's testy being a mortal sometimes. But therein lies the gist of this 'test'- how well can you cope with the things that life presents you- that is one of the rocks in the jar as opposed to the sand. This incident of mine, and the errors some of you have mentioned are but specks, though it sure didn't seem so last night. I was starting to envision things like cam gears, where one has 40 teeth, and the other 'happens' to have 79- or other more realistic things like threaded rod measuring up to have 19.7 threads per inch instead of 20, etc.

                        Anyway, I have the new rod circle made and fitted, not epoxied yet, and there will be no loss of concentricity, etc, and the project and I will survive. Thanks again for the support.
                        I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

                        Comment


                        • #13
                          Postage

                          Originally posted by tony ennis
                          We computer geeks call that an 'off-by-one' error and it's probably the biggest re-occurring programming error.

                          Originally posted by Evan
                          Yep, except I have always heard it called a "fence post error". Example, how many fence posts does it take to make a fence with 10 spans of wire?
                          Yes, Evan,
                          that is the corollary of it.

                          The error in the first instance was counting zero as one - as in measuring a distance.

                          Your example was an error in numbering - ie in 10 spaces - has two variations:
                          1.
                          assuming that the fence started with a post there is a post at zero, hence there are another 10 posts for 10 spaces hence 10 +1 = 11 posts; and

                          2.
                          assuming that the start of the fence was not a post but say was fixed to a wall (or a pre-existing post/fence) there are only 10 posts required for the 10 spaces - ie the first post was at "1" and not at zero.

                          But back to the unfortunate events regarding the rotary table, I would have thought that the increase in diameter to accommodate the 1 extra space in 360 would not be very big at all.

                          Even if that were not the case, would it make any functional difference if a new 360 "space/tooth" ring of all-thread were used with a little of the outer "crests" of the "teeth/threads" removed to get the same outside diameter as the previous deficient "ring"?

                          Comment


                          • #14
                            Originally posted by darryl
                            I had a similar problem with some drawer slides I installed- final dimensions were off by about 1/16, and I'm using them but it's tight. It eats at me a bit each time I open a drawer. Talking about that 1/16- I bought a tape measure the other day and remembered the experience I had with one being short by that sixteenth. I went through about 6 or 8 tapes before I found one that read properly. It was the cheapest one there too, so now I'm the proud owner of a piece of crap that measures correctly.
                            S.O.B.
                            Well, that accurately describes my current project. I've got a cabinet that is 24 and 3/4 wide with a pair of doors that are 12 and 3/8 wide. Check the doors just before doing the glue-up and walking away and I'm about 1/16th of an inch wider than the cabinet. Of course I'm using the tape to measure, because 24.75" is just outside of the range of all of the solid measuring products I own...

                            The kicker is that I know better than to use the end of the tape for anything that needs better than 1/4" measurements. I am beginning to think that the measuring tape is more dangerous at 2a than the power tools are!

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                            • #15
                              When I was a kid I 'fixed' my dads tape measure by tightening the rivets on the end. I thought that it was loose- and I guess I shouldn't be surprised that many people don't know the use of that looseness. It's there because the tape can be used for both inside and outside measurements. The amount of looseness is equivalent to the thickness of the hook on the end. If you can measure by hooking over an edge and making a mark, then clamp a block to that edge and remeasure by pushing the hook up to that block, the reading should be the same. I haven't found any significant error on that account, just error in the actual length reading because the rivets are in the wrong spot. You can't make either reading (inside or out) properly in that case.

                              My dads response to my fixing was 'well, that tape's no good anymore'. I was perturbed until he showed me how they are supposed to work.

                              By the way, I checked a Stanley (good solid brand name) and it was out- why pay $12 plus tax for that when you can get the same error in manufacture for $2- I got my good one for less than that, but I had to test several before I found a good one. I would recommend for anybody buying a new tape to check it in store first.

                              I finally took my new baby out of the package and used it. It measures accurately, so fine. I put the batteries in it for the light, and got my moneys worth just in laughs. Even in the dark, I couldn't read the tape with that pitiful weak red led focussed off into space somewhere. Replaced it with a bright orange led I had, and now it's a mercedes. Whoooohooo!
                              I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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