Small Engines (Lawn Mowers, etc.): Drill Bit Size, sheet metal screw, screw threads

Question
I would like to know the proper size hole to be drilled for use with a # 10 sheet metal screw.

Answer
Hi Ray,

I just checked and can't find any charts that list the proper sizes.  Since #10 screws sometimes vary, I choose a drill that is slightly bigger that the INSIDE of the screw threads.  The bigger you go from there with the drill size, the easier the screw will go in but the less the thread contact area will be and the less the holding strength. This also applies with tapping machine threads.

Best,
Michael