We’ve been using this basic JD Squared TN-100 tubing notcher for over 15 years. It uses common bi-metal hole saws to make notches in the tubing. You use different-sized hole saws to fit the material you are working with. The cutting angle of the TN-100 is adjustable and features engraved degree marks. A single hole saw will last for more than a few ’cages if you are careful and cut slow. It’s best to not use cutting oil because it will contaminate the welds if you don’t clean it all off the tubing.