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Need help drilling holes in pipe

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  • Need help drilling holes in pipe

    I have a 24" piece of 1/2" emt that I need to drill a 1/4" through hole I" from each end. I need to place the holes so they are in line and perpendicular to the axis of the emt. My initial attempt was not successful as the 1/4" holes did not line up. So thought I would present this problem to the members and see what methods they have found to be successful. Thanks Paul

  • #2
    Clamp the piece to the table and scribe a line, I use a height gage, at the center of the pipe, bar or tube. Drill the hole on one end. Unclamp the piece and relocate on the table, using the height gage to line up the pipe on the scribed line, drill the other hole, after reclamping the pipe. If possible, use the table T slot as a V block, otherwise you will have to use a guide fence. It's quite easy.
    I've done this to cut key ways when the part is longer than the table travel.


    • #3
      What equipment you have available?
      Location: Saskatoon, Saskatchewan, Canada


      • #4

        When I need to keep an established plane when bending long tubes, I use a clamp with a flat plate welded to it that grabs one end of a pipe or tube. Place a magnetic level on the flat plate with the bubble axis perpendicular to the pipe and level it with the clamp.

        Drill one hole by laying out the center top axis, or locate the center of the pipe with a plug turned with with a 1/2” shank on one end and the diameter of the conduit on the other. Place the plug in the drill chuck and then clamp the conduit size end in the vice and lock the vise down. Now when you remove the plug you will be on center.

        Turn the tube end for end or slide the tube to the new location and level the pipe and your next hole will be in the same plane as the first one.
        ARS W9PCS

        Esto Vigilans

        Remember, just because you can doesn't mean you should...
        but you may have to


        • #5
          Thanks for the above helpful replies. I would like to read more on this subject and wondered if anyone could recommend any books or other references dealing with layout and alignment of round objects. Thanks Paul


          • #6
            Get a piece of scrap angle iron. Size unimportant. Clamp EMT to inside of angle iron. Clamp a board as a fence on your drill table to determine center. Drill away.

            If you have V blocks with clamps you could do it that way too. Your goal is to stop the pipe from rotating between drilling operations.

            You could even clamp it to a scrap piece of 2x4.


            • #7
              Yes, the equipment that you have available will determine how you go at it.

              For instance, if you have two identical or similar drill press vises, then you could clamp it in one vise at one end and drill there. Then, with both vises on a flat bench (or mill table) you could clamp it on the other end with the other vise before removing the first vise. Remove the first vise and then drill the second end.

              A variation of this with one vise would be while still clamped after drilling the first hole and working on a flat bench or table, clamp a block of metal or wood in the middle. Carefully remove the vise from end one and move it to end two. Then remove the middle block and drill it again.

              Another way would be to drill one end and reverse it in the vise. Then put a 1/4" rod in the drilled hole and use a level to make the rod vertical as you clamp the vise tight on the second end. Then drill.

              Probably a lot more ways.

              How about two drill presses?
              Paul A.

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


              • #8
                Drill a 1/4" hole in a board or plate longer than 24" near one end. Put a 1/4" pin or bolt in the hole. Drill a 1/4" hole in one end of the EMT. Slide the drilled hole over the pin or bolt. Now drill the second hole. They should be parrellel. Works best with a drill press, but would work with a hand drill depending on tools available
                Sole proprietor of Acme Buggy Whips Ltd.
                Specialty products for beating dead horses.


                • #9
                  Many thanks for all of the useful tips. I was planning on drilling some 5-8' lengths of emt and the idea of attaching them to a 2x4 should make this possible. Paul