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drill bit and tap sizes

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  • drill bit and tap sizes

    I don't know if this is important to anyone, but here you go. I made a spread sheet of all the metric tap sizes and drill bits along with the fractional equivalents. The ones with a * next to them are spark plug sizes.

    (that's the spread sheet with all of BP's additions, thanks )
    Last edited by arsenic; 04-01-2008, 12:46 AM.

  • #2
    for anyone wondering, yes I do have too much time on my hands


    • #3
      FYI- This came in so handy today, so THANK YOU SO MUCH!!!
      1993 Suzuki Katana 750 (GSX750F)
      1993 BMW 325i


      • #4
        Good list Arsenic..
        Some notes and additions:

        Most times the drill called out is for what is known as 75% tapping. This is standard. Smaller drills will allow higher engagement but run the risk of binding while tapping. Larger drills, less engagement but run the risk of the screw pulling out the threads at torque.

        The softer the material the coarser the thread. Coarse threads are deeper and allow more material to be in sheer. Don't be fooled into using a fine thread thinking you have more threads so better holding power..

        Sharp drill will cut undersized. Dull ones over sized and hand drilling is generally over sized as well. When hand drilling something around 4mm to 5 mm I use a smaller drill.

        I added a few sizes that are accepted for metric as well as some eye balled sizes. There are 4 major types of drill available at good hardware stores/ machine shop suppliers:
        Fractional (drills sized by fractions of an inch in 1/64th increments)
        Numbered (drills sized numerically. Larger the number the smaller the drill)
        Letter (these take over after number drill #1.)
        Attached Files
        Last edited by Black_peter; 11-26-2007, 01:09 PM.


        • #5
          thanks BP, that's awesome. I just put what I knew worked, I didn't have that so important work shop cross over.


          • #6
            I HIGHLY recommend this website for mm or # or letter drill bits.
            I ordered a 4.3mm drill for $4.60 shipped to my door.
            Last edited by arsenic; 01-24-2008, 03:39 PM.


            • #7
              Son of a gun..
              I built this when I was in 5th grade..
              (from the plans not a kit)


              • #8
                here's an SAE to Metric conversion chart by 64th of an inch. I've seen these charts, but only by 16th, so I made one.

                Last edited by arsenic; 03-31-2008, 11:36 PM.


                • #9
                  This should really get stickied under Mechanics 101 maybe under how-to as well..


                  • #10
                    it IS a sticky in mechanics 101. I made sure of that before I posted it
                    Last edited by arsenic; 02-09-2008, 03:56 PM.


                    • #11
                      Just wanted to add a little something.

                      Millimeters > Inches = Multiply by .0393701 , Example 10mm x .0393701 = .393701 inches

                      Inches > Millimeters = Multiply by 25.4 , .375 3/8" x 25.4 = 9.525mm

                      Last edited by Tmod; 06-25-2008, 08:21 PM.


                      • #12
                        good information to know, I swear 25.4 is muscle memory for me


                        • #13
                          Very useful to print out & stick on the garage wall for quick referance, beats hunting for the zeus book

                          Renthals & twin spots do not make a streetfighter !


                          • #14
                            One reason I keep Machinery's Handbook close at hand in the garage when makin chips! Good info for anyone making/repairing threaded parts.
                            2006 Katana 750 - Daily therapy
                            2005 ZZR1200 - Weekend therapy


                            • #15
                              Originally posted by diavolo View Post
                              One reason I keep Machinery's Handbook close at hand in the garage when makin chips! Good info for anyone making/repairing threaded parts.

                              I bought a 1952 edition with unused cover and sales receipt at a yard sale for $3... The guy broke the spine in perfectly. Every page opens and stays open.. One of my prized books..