I can't afford a mini Milling machine or a CNC router setup, but I want to cut a straight edge on some 3/16" thick aluminum bar. I'm thinking I can do it with my router table but I've read an end mill bit works better than a carbide router bit. I've found some end mills for sale but I'm curious about the nomeclature on the ad ? What does it mean when it says 'cutting length' as opposed to cutting diameter ? As in -> High-Speed Steel End Mill, Aluminum Cutting, High Helix, Uncoated (Bright), 2 Flutes, Square End, 1/2" Cutting Length, 3/16" Cutting Diameter.