3/32" dia. shanks are the jeweler's preferred standard for burs and small rotary tools. They fit the adjustable chucks found on most flexshaft handpieces as well as 3/32" handpiece collets.
Setting Burs are similar in shape to hart burs, but with straight sides. They are used primarily for cutting seats in prongs, bezels and tube settings, often roughing out seats that are then refined with a hart bur.
Vanadium Steel burs are economically priced. They cut precisely when new, but don't retain their sharpness as long as other steel alloys.