<HTML><HTML>Jason-- To "nondestructively" measure tuning pin holes I might suggest that you use an interior gauge such as made by L. S. Starrett. [You can find these units on their website] Each gauge features a split ball which is expanded until it touches the hole walls; then measure the diameter with a micrometer to get your size. Very convenient and a good, traditional design. Cost about $85 a set as I recall. Dave Talcott</HTML>