Have a good file!! My old files weren't impressing me this year, so off to the local hardware store. Was gonna buy a double cut for changing the angle on my Deltas and a single cut to make em sharp enough to suit me.
They had a handy file by Nicholson with a built in handle which I added some quick bocote scales to when I got home. It's double cut on one side and single cut on the other. Bout $11...
Had this Delta from factory edge to shaving in about 90 seconds! Wish I'da got a double cut file 20 years ago!!
The only thing I dislike about Deltas is laying that angle back to get a razor edge.
Get em sharp, you won't regret it!! :D