2 Replies Latest reply on Sep 4, 2007 4:40 PM by Eddie Cyganik

    Formula to Calculate a Bolt Hole Pattern

      I was wondering could someone help me out.
      I'm trying to find out what the Trig formula for calculating a bolt hole pattern for a given radius and a specific # of holes.
      I want to create a set of variables so the user inputs the arc radius and number of holes req'd. And then it plots the centers accordingly.
      I'm actually using this in another application for our cnc router with a pgm called woodwop 5.0
      I'm just not sure what the equations should be set up like to do something like this. Any help would be greatly appreciated.
      Thanks in advance
      Brad
        • Formula to Calculate a Bolt Hole Pattern
          Martin Stevens
          I just stumbled across your question. If you've not figured thisout by now...
          I will still make a suggestion for others who also 'stumble across'this topic.
          Though i've not tried to set this up myself, I do use the formulato calculate chord length often. Here goes: 180 / number of holes =a
                                          chordlength = sin a * P.C.D. 

          Just remember that if you want to use any trig formula in Excelthat all angles have to be converted to radians before the functionis applied to the value.
          e.g. for same formula above: 180 / number of holes = a
                                                              a* pi / 180 = r
                                                             chordlength = sin r * P.C.D.

          Refer to the help file in Excel how to use formulas. For example pi/ 180 should be entered as PI()/180

          Hope this helps someone!
          • Formula to Calculate a Bolt Hole Pattern
            Eddie Cyganik
            Hey Macgeyver,
            What kind of question is that?
            I remember in one of your earlier episodes,

            ...you took a washer, pocket lint, a piece of chewing gum and some clam shells to trigger-out how to defuse an atom bomb.

            ...Come on, use your noodle.