Rick6a
Well Known Member
Quick now....off the top of your head....what size would you ream a hole to accept a #6 screw? What is the diameter difference between a #40 and a #41 drill bit, a 1/8" and a #30 drill?, a 3/16" or a #12 drill bit? To what undersize size dimension would you predrill a bolt hole prior to final reaming it to accept an AN4? What size is larger....19/64" or an "N" drill? Could you use a type "V" drill instead of a 3/8" drill bit? Some close tolerance 3/16" interference fit fasteners are inserted into .1850 holes....what reamer size would you reach for? What size drill bit equates to .1850? To be sure, you may not be installing very many precision fasteners into an RV airframe, (I did) but such information is still nice to know or at least have available at your fingertips.
Every home shop should have some version of a drill index chart available for quick and ready reference. In the production shop I came from, such charts seemed to be hanging everywhere. So dependent am I on the chart's usefulness, I must have at least 6 displayed including my basement shop, garage, hangar, and even taped inside tool boxes. The knowledge is free. Take advantage of the drill index chart's unending usefulness and build even higher quality into your dream project.