Plane iron is the blade inside a planer, a tool used to remove wood in small increments. There are some things to watch out for if you are going to grind and hone your own blade and a few mistakes not to make.
Step 1 - Grind
The blade needs to be at a 25-degree primary bevel. Grinding is going to do this for you. Using a silicone carbide stone is recommended because of the ability of the bench stone to give you a flatter surface to grind and a better angle. Don't try to use a grinder and do it quickly if you have never used one before. Oil the surface of the stone in front of the blade you are using to get the bevel to the correct angle. Don't overcompensate. Pushing too hard can nick the blade. Use an even stroke.
Step 2 - Hone
After you get the angle to a 25-degree bevel, then you need to sharpen or hone it. Do this using the micro finish abrasive paper and the glass on a flat surface. Do not use coarse paper as it will pit and chip the edge of the iron. A fine grit puts a good, smooth finish of the edge. Push and pull at the correct angle to get both sides sharpened.