Knurling tool. By TheDacchio. 12:37 video:
https://www.youtube.com/watch?v=QSP2JjTaAA0
Previously:
https://www.homemadetools.net/forum/...815#post171162
https://www.homemadetools.net/forum/...971#post168056
https://www.homemadetools.net/forum/...885#post167749
https://www.homemadetools.net/forum/...642#post167017
https://www.homemadetools.net/forum/...200#post165397
https://www.homemadetools.net/forum/...217#post165440
