To change the drill bit on your Makita 6510LVR 3/8" Heavy-Duty Drill, follow these steps: Put the drill in reverse mode: Push the button switch to set the drill in reverse function or counter-clockwise rotation. This will allow you to loosen the chuck. Hold the chuck firmly: With the drill in reverse mode, gently grab the front half of the chuck and press the trigger. This will open the chuck jaws. Insert the new drill bit: Take your new drill bit and insert the end portion into the chuck. Make sure it fits snugly. Tighten the chuck: Once the drill bit is in place, release the trigger and rotate the chuck in the clockwise direction to tighten it securely. And there you have it! Your Makita 6510LVR drill bit has been successfully changed. Happy drilling!