Tony,

These brief articles explain why drills make odd shaped holes in sheet metal and offer a suggestion to solve the problem:

http://timbobtastic.com/hints-and-tips/drilling-a-round-hole-in-sheet-metal/

http://www.giangrandi.ch/mechanics/sheetmetaldrill/sheetmetaldrill.shtml

Pretty interesting, huh?

Last edited by yar; 07/19/2017 4:05 PM.

Ray