Place a length of hard-metal tubing with a 1/2-inch inside diameter on a work surface. The hard metal may be steel; avoid using soft-metal tubing such as copper.
Measure 6 inches from one end of the tubing. Mark the 6-inch point with a permanent marker.
Adjust the jaws of a tubing cutter with the cutter's knurled adjustment knob. Place the tubing in the jaws of the cutter, positioning the tubing so the cutter's blades are at a right angle and will cut straight across the tube.
Turn the adjustment knob to close the jaws. Continue to turn the knob until the cutting blades are positioned against the metal tube.
Hold the tube securely with your hand. Rotate the cutter around the tube one time. Turn the adjustment knob 1/4 turn to tighten the jaws and cutting blades. Rotate the cutter around the tube once again. Continue to tighten and then rotate the cutter until the tube is cut completely.
File the ends of the tube to smooth them. That prevents metal splinters during the tube's use as a T-post clip tool.