On bound fingerboards, I nip the tang away under the overhang, and file the underside of the end until it is as perfectly flat as I can get it. I also lubricate the fret slot with tight bond before inserting the fret--wiping off squeeze-out as I tap the fret in.

On bound fingerboards, I nip the tang away under the overhang, and file the underside of the end until it is as perfectly flat as I can get it. I also lubricate the fret slot with tight bond before inserting the fret--wiping off squeeze-out as I tap the fret in. This doesn't actually glue the frets in, but after the glue dries it does give the tang something to "bite" within the slot. It is a fairly common practice, I believe. Benedetto demonstrates it in his instructional DVD. I take an added precaution BEFORE putting on the binding or inserting frets: I file a chamfer in the top of each fret slot--about three strokes with a triangle file across the full width of every slot. This helps the fret seat tighter to the fingerboard surface. If any fret ends pop back up (it's fairly common to have one or two of those) you can put a tiny drop of watery CA glue under the fret end and then hold the end down with a screwdriver for 30 seconds or so. That will usually keep them down. Of course, you need to be quick about pressing the end down!