Vintage Group of 9 Bits. There are 7 auger bits, one twist drill bit, and one flat-edge screwdriver bit. They were manufactured in the USA by Irwin, Stanley, and others. The bit sizes, in inches, are: 15/16, 14/16, 13/16, 9/16, 8/16, 6/16, 4/16, and 3/16.