Got the burner off #7644 for the bottom tube plate inspection - checked grate, nice and clean, no rusting surprisingly -
One segment of burner holes on the edge of the passenger side of the burner plate are 1/16" diameter, a 1/16" drill passes throgh them ok. So assumng this was the orignal hole diameter.
All the other holes are (now) very slightly smaller - a 1.5mm drill passed through them ok. This is only a 11% at most reduction in area, so is is it really worth running the 1/16" drill through all the holes before the burner goes back?
I've recently bought a 20HP 24" burner off that well known expert Don Bourdon. During the build, Don sent me a lot of burner info including 2 articles he published in 2012.
Concerning hole size in burner plates he says:-
Standard hole size is #54 (0.055"dia ~ 1.4mm). For increased performance each hole can be enlarged to #53 (0.0595"dia ~ 1.5mm). Increasing hole size larger than #53 is not recomended as the burner will howl more or less constantly and be prone to backfiring.