Rivets are mechanical fasteners with a head on one end and a cylindrical stem known as a tail on the other end. Fractional, Letter & Number Drill Sizes Millimeter & Decimal Equivalent tel. Another type of specialty drill bit, rivet drill bits are specifically made to drill rivet holes into thin sheets of metal. On this subject, Trautwine says: 'No trade stupidity is more senseless than the adherence to the various Birmingham, Lancashire, etc., gauges instead of at once denoting the thickness and diameter of sheets, wire, etc., by the parts of an inch, as has long been suggested. Best for: Drilling rivets into thin sheets of metal. The relation between these arbitrary designations and actual sizes is about as remote as is the stupidity of a modernistic composer from sanity. In manufactured parts, holes with female screw threads are often needed they accept male screws to facilitate the building and fastening of a finished assembly. He has this to say on the subject:Īrbitrary Gauge Sizes: The practice of designating sizes of wire, sheet metal drills, etc., by arbitrary numbers and letters has been the cause of much confusion among manufacturers and customers. Chart showing conversions for fractional inches, letter/wire gauge, decimal inches, and metric: Fractional/Decimal Equivalent Drill Sizes Chart. Below is a comprehensive drill and tap size chart for all drills and taps, imperial and metric, up to 36.5 millimetres (1.44 in) in diameter. Used where more precisely sized holes are required in larger sizes than number drills. Details about 8-32 tap drill, 10-32 tap drill, 6-32 tap drill. The tap size chart on this page is the list of standard size drill bits in different measurement systems that include fractional, metric, wire gauge number, and letter. Last night I decided it was about time I got around to reading my 1942 edition of 'Audels Machinists and Tool Makers Handy Book' by Frank D. The best way to produce the thread holes is to drill a hole of the right size with a drill bit & tap it with a tap.

Letter size drill bits chart