FWIW, I just finish installing a NECG banded front sight. In lieu of using adjustable reamers, I used the lathe. For reference purposes, the band had an ID of .650, and the OD of the barrel was .665.
I indicated the band, ramp towards the spindle, in a 4-jaw chuck. To avoid marring the band with the chuck jaws I 'wrapped' it with a small aluminum strip cut from a 'beverage' can. Then I used a boring bar, hand turning the chuck initially, to take out the required amount. I then turned the process over to 'power' - very slow feed, and about 300 rpm. After each cut I stopped and inserted the barrel thru the spindle into the band to check for fit, as well as from the front. When I got the point where the barrel would just enter the band from the front, but not when inserted thru the spindle, I took a .002" cut. At that point I removed the band and checked for fit, again, and again. With a little effort, some light heat, and a little tapping with a rawhide mallet, was able to get the band positioned where I wanted it, and the ramp resting properly on the barrel. With the band press fit on and aligned, I made an index mark thru the hole for the allen-head screw. With that done, I let the barrel and band cool. After cooling I masked the barrel to mark the rearward position of the ramp, as well as placing an index mark on the ramp and masking tape for alignment. From there I set-up the barreled action in the mill, and drilled a .125" dia, .015" deep pilot for the allen-head screw.
After all the machining was done, the barreled action was set in a vice, the band and barrel degreased, and band aligned and affixed with Loctite 620 (acquired from the local Fastenal), and the allen-head screw tightened. Cleaned up the excess 620 with acetone and that's how it sits as of now. I'll have to wait to see if my effort paid off.
As a second thought, and I may try this on a piece of scrap, but I'm wondering if one could mask off the band and ramp, apply a release agent (Brownells, One-Shot, paste wax, etc) to it, remove the band, clean and degrease the band again, and reinstall using the 620 and see if release agent will work with the 620.
