When i file broad heads at home, especially new ones, I use a broad head/arrow holder. Nothing more than a cut off from an ash canoe seat. They make them with extra length and they always need to be cut to length. Anyways, I grind a slot to harness the arrow and taper the end so the blade edges remain supported but clear of the wood for the file. i think 3rivers sold a plastic hand held arrow support. They help to get a consistent firm file stroke, which can be difficult with narrow heads. Way back when for three years in a row, I gouged my index finger on my shooting hand, right where the string bit me, sharpening Hill heads prior to the season opener. Two times it was the corner of the head digging a hole in me, another time a nasty cut when it turned in my hand. I switch hands when filing, the left hand index finger has been cut as well, but i really remember the right index finger cuts back when I only shot right handed. One year,1976, I shot a deer with the middle and ring finger under, with the stitched index finger still heavily bandaged sticking out straight, it was a very close shot.