The steel edges on a board are there for two reasons: to help it turn, and to protect it from impacts. You only use the part of your edges that contact the snow, this is called the “effective edge. If your board has a “full wrap edge that goes around the tip and tail, it’s only there for protection, since those areas are turned up from the snow.
First thing is to take your file and dull, or de-tune, your tip and tail. You can really get after it here with the file since you don’t use this part of the edge to turn, just be careful not to go into your effective edge. If it helps, you can lay your board on the ground or up against a wall to see where your edge starts to hit the snow.
Whenever your edges hit rocks and things, the friction causes the steel edge to harden and create a rough burr. You can feel these along your edges after a few days of riding. Just be careful because really bad burrs can cut through your skin, and if they’re that gnarly you can imagine how it effects your turns. A file can’t cut through these hard spots, and will make a zzziipp noise if you try to file over them.
Get rid of burrs by using a pocket stone. Wet the stone with water, snow, or spit to lubricate it, and rub it along your base and side edge several times. The stone is made to smooth out the case hardening of the steel and will then allow your file to cut.
The next step is to understand the geometry of your edges. Your edge is one piece of steel made up of two sides: the base edge and the side edge. When your board was built at the factory the edge was put in so the base edge was flat to the ground and the side edge was straight up creating a 90-degree angle. The problem is that if you’re riding your board flat on the snow or sliding a rail, the flat base edge is very likely to grab the snow or catch the rail and throw you somewhere you don’t want to be. The solution is to angle, or bevel, the base edge away from the snow a bit with a file.