1967 Gibson L5 fret polishing restoration. My father Dr. Phil Petillo invented a process of micropolishing that is used with his patented Petillo Precision Frets and I apply this process to every set up I do. The idea is the frets are polished from 400 grit sand paper all the way up to 10,000 grit lens paper (which polishes telescope lenses). The entire idea is to make the surface area so glass-like the metal string can resonate a clear true note with intonation clarity. I always use the example with the wine glasses filled with liquid and the player rubs the rim...and the friction of that motion makes a note. You can image if the rim was rough, it would not be as reflective to carry the note. That is the principle with polishing the frets to so fine and flawless a gloss...the notes hang in midair. #gibsonL5 #L5 #jazzbox #fretdents #frets #polished #micropolishing #lenspaper #gibsonguitars #luthier #guitarbuilder #guitarmaker #intonation #glass #friction #byhand #craftsmanship #telescope #lenses #rust #beforeandafter