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Bolt Blanks 1 1/4 X 7 tpi x 8"

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  • Bolt Blanks 1 1/4 X 7 tpi x 8"

    Got a strange request from a customer today. He has 6 bolt blanks 1 1/4" Grade 5 and wants them threaded to std. UNC 7 tpi about 5" of the 8" length. On one end he wants a 1" hole perpendicular to the shaft. I'm assuming this thing fits on a pin and then threads into some sort of alignment assembly. Anyway, I don't have a sample yet, but I was still curious.

    One, what should one charge, and Two, probably the most important, how much of a bitch is Grade 5 going to be? From what I've read so far, it's case hardened so that could make things awfully interesting in the threading dept.

    Any ideas would be appreciated.
    Wayne

  • #2
    First, grade 5 should be no problem. You can turn and saw grade 8, it just takes more effort so 5 should be a piece of cake. If it's really grade 5 it's not case hardened, but if it's hard it shouldn't be a grade 5 any longer.

    I'm a little puzzled at the description of what the customer has and wants. Drilling a 1" cross hole in a 1-1/4" shank doesn't leave much so his load had better be in compression. If so, not a problem. But if this is mounted on a cross shaft, what function does a bolt head have any longer? It could just as well be a length of 1-1/4" round stock with a thread on one end and a cross hole in the other. I'm missing a gear in the train somewhere.
    .
    "People will occasionally stumble over the truth, but most of the time they will pick themselves up and carry on" : Winston Churchill

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    • #3
      I suspect you have it correctly. Pitch out the hex head and replace it with the cross hole. He said "bolt blanks", but like you said, it could just as easily be a piece of 1 1/4" round stock, Grade 5.

      In any event, I assume I will be called on to thread 5" of Grade 5 bolt stock, whatever it might be, along with the cross hole. I was just curious what evils awaits me.
      Wayne

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      • #4
        Originally posted by atty
        I suspect you have it correctly. Pitch out the hex head and replace it with the cross hole. He said "bolt blanks", but like you said, it could just as easily be a piece of 1 1/4" round stock, Grade 5.

        In any event, I assume I will be called on to thread 5" of Grade 5 bolt stock, whatever it might be, along with the cross hole. I was just curious what evils awaits me.
        None. Grade 5 will be a quenched and tempered medium carbon steel. It is tempered for strength and not hardness. It will machine like mild steel.

        For reference -
        Low Carbon Steel: <0.15% carbon
        Mild Steel: between 0.16% and 0.29% carbon
        Medium Carbon Steel: between 0.30% and 0.59% carbon
        High Carbon Steel: between 0.60% and 0.99% carbon

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        • #5
          I had to extend the threads on some 1'' anchor bolts for a customer . Those bolts were harder than grade 5 by about triple , trying to single point it would have been way to time consuming so I chased them with a split die and die holder with the handle resting on the compound. I had to make three passes on each anchor tightening up the die each pass or the anchor would just slip in the chuck.
          Eight anchor bolts took about 3 hours, The customer was happy that it could be done and was pleased I only charged him forty bucks a piece.

          Steve

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          • #6
            Thanks for the info, guys. I, too, was wondering whether to fight with a die, or just single point it. I cut a test piece last night on the lathe out of 12L14 and no problems, but that's a far different creature than Grade 5. Guess I'll just have to wait 'til I get one of those things in my hand and see.
            Wayne

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            • #7
              Just spitballing here, but there's a possible problem if they truely are bolt blanks. Bolt threads are usually rolled. I am not sure that this is the case with grade 5, but if it is, then the blanks may be undersized in the area to be threaded by a considerable amount. This could mean that you don't have enough meat to cut a standard 1 1/4" thread.

              You might be better off if you get some actual bolts and just extend the threads to the length needed. Or get some longer bolts and cut off the existing threads if you fear the transition from rolled threads to cut threads.
              Paul A.

              Make it fit.
              You can't win and there is a penalty for trying!

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              • #8
                Update

                First of all, thanks to everyone for their thoughts. I know none of you have ever experienced a customer who gives you a phone description of a project only to have the raw material arrive in a form that is not exactly what you had in mind. He did say 1 1/4 X 7, and he did say a hole perpendicular to the shaft, but I don't recall anything about drop forged castings and a lollipop at the end.

                Anyway, the good news is that it turned out to be 1035 steel rather than Grade 5, case hardened bolt steel, so threading went a little better. I did have a lot of fun, however, getting these things lined up in a 4-jaw with that rough, forged outside. You learn to take an average on the dial indicator. Fortunately, Chicago Hardware, the bolt blank manufacturer, had machining in mind as they cast the blanks at 1.360" leaving plenty of meat to turn down to 1.250" before threading.



                Finished product:

                Wayne

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                • #9
                  I would never have guessed the shape from the job description, nice job by the way!!

                  Peter
                  I have tools I don't know how to use!!

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                  • #10
                    Ah..Toggle bolts,nice threading job BTW!

                    Oh,charge plenty,Toggle bolts that size aren't cheap and don't come std. with that thread length.
                    I just need one more tool,just one!

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                    • #11
                      Thanks guys. I would love to charge plenty. It is the biggest threading job I've ever tackled, but unfortunately, he's a good customer for other things, so it's one of those once-a-year grunt jobs that you kind of suck up for the greater good.....hopefully. If he saw the hours/bolt, he would pass out.
                      Wayne

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                      • #12
                        Okay,just remember,customers are like stray Dogs,once you start feeding them they come to expect it
                        I just need one more tool,just one!

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                        • #13
                          Nice job. Which method did you use to centre drill the ends?

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                          • #14
                            :-) Never in my wildest imagining would I have come up with that
                            device from the initial description. :-)
                            ...lew...

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                            • #15
                              Originally posted by bob ward
                              Nice job. Which method did you use to centre drill the ends?
                              Yes, I'd like to know that too. How did you drill the lollipop in the middle?
                              I'm guessing with a drill press and some 'estimating' but I'm also thinking the hole center should be in-line with the thread axis and the hole axis should be perpendicular.

                              Not easy.
                              Mike

                              My Dad always said, "If you want people to do things for you on the farm, you have to buy a machine they can sit on that does most of the work."

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