If the groove is fairly deep, a 6" grinding wheel is used, and if shallow, a Dremel 1/2" sanding wheel does a good job followed by a stone. When the Dremel is used, the sandpaper wheel has to be at an angle to the groove lest it deepens the groove. I use only through hardened frizzens and use a 4" length of 2" dia. pipe that's capped on one end and the cap has some holes drilled in it. The frizzen is wired up, placed in the pipe and heat is applied w/ a Mapp gas torch. When a bright red is reached, the frizzen is dunked in motor oil and is swirled about in the oil. The frizzen is then placed in the oven at 375 degrees {my oven has been checked} for 1 hour. The pipe concentrates the heat and causes the frizzen to attain an even bright red. The toe area of the frizzen is polished and is then hit w/ a fine flame until a bright blue and is cooled in oil...Fred