Awww Brian, you took all the fun out of the project when you told Sapwood to only glue one end on!
Sapwood
I asked the same question about a year ago to get a feel for what everyone else was getting for file life and got the same sort of answers that you are getting now. No definitive number of sharpenings or such. Like Brian said, "When it isn`t throwing metal shavings or it feels like it is just polishing, I toss it and grab a fresh file." I have another criteria also. If I can`t freshen up a wood dull edge in three strokes or less, the file gets pitched.
They are cheap by the dozen with many suppliers selling them for $9/dozen or less. Try Jeff Sikkema, CCD, Bailey`s, Madsen`s, Cutter`s Choice or the file king himself, Don Brown(AS name Don), better known as roachjob on eBay.
I`ve had the best across the board reults from the swiss made files.
Russ