We all have our preferred method of touching up our broadheads and who's to say which way is best. Sometimes I file serrations on the blade and sometimes I don't, it depends on the broadhead and my mood.
I've also did it the way Charlie does with the edge of the file but I haven't honed it again after doing that. I find the older I get the more set in my ways I am an I just do things the way I've always done them.
A friend of mine is a well known flint knapper and has killed a bunch of critters with the heads he has knapped. He was at a big shoot some years back and was showing a group of younger guys how he sharpened a steel point by putting a burr edge on the head with the edge of a file. One of the guys ask him why he didn't use a shaving edge to which he replied, "I don't wanna shave em, I just wanna kill em" He wasn't trying to be funny, he was serious.
That friend was old Norm Blaker, I call him old because he just a little older then me.
