Finding the closure
It is not uncommon for a chuck to get a little out of tune and not completely close as a result. At best, this lack of closure can be unpleasant; However, most of the time it can reduce your productivity. This is not OK. – Keep your drill tight and your mood above water with these few steps to help you quickly close your chuck.
The first is the first:
As you know, you will find a chuck screw in the center of an open chuck. This screw is responsible for a large part of keeping your chuck where it is supposed to be. However, like all things with a job to do, occasionally these little screws can lose their way. Sometimes the screw can be completely lost, but in any case it just needs a little direction. Because a loose or missing screw will prevent the chuck from closing completely, you must tighten or replace the screw. Remember that this screw is reverse threaded. Therefore, to tighten the thing, you need to move your wrist to the left (counterclockwise) and turn the screw counterclockwise. Once the screw is secure and tight, the chuck should close and grip as it should.
Returning by seconds:
If the chuck remains loose or continues to return to the out of control position after the chuck screw has been tightened, there are a few other factors that could be at play: First, the screw or the screw hole itself (inside the chuck) may have stripped threads. This would prevent the screw from staying in place which, in turn, prevents the chuck from being held tight. If the screw threads are stripped, replacing the screw should be sufficient. However, if the screw hole inside the chuck is removed, you will probably need a new chuck.
For one reason or another, the chuck may also be locked or rusted in a loose position, or the fingers inside the chuck may have slipped, bent, or broken preventing the chuck jaws from gripping slightly. – In these cases, the chuck needs to be replaced or professionally inspected.
Now that we’ve come to the end of this story, I think the moral of the story is, “keep the screws tight (or you’ll end up with a screw loose”, yes, pun intended). Good luck with your chuck and remember that a tight drilling requires a tight drill (chuck).