Each ALUMINUM SCREW POST assembly consists of one post with a  .203 diameter
and  an outside head  diameter of .415,  and one 8-32 thread slotted screw with an
outside head diameter of .415.  Otherwise known as 'Chicago Screws', Binding Posts, or
Sex Bolts, the low profile, matching head on both the post and the screw allow for a nice
clean look. Available in lengths 3/16 to 6".   The proper drill size is 7/32.