Removal of chuck

Usually drill motors have a reverse (left) thread retaining screw located in the center of the chuck. The chuck however is typically threaded in the normal right hand configuration. Once the retaining screw is removed place a 1/4" allen wrench short end into the chuck and tighten, next strike the allen wrench with a soft tip mallot (counter clockwise while holding on to the drill motor firmly. This should loosen the chuck, then simply unscrew the chuck by hand. Good Luck!

open the chuck jaws right up
down the center of the chuck you will see either a philips screw head or a hex head for allen key
hold the shaft at the base of the chuck to stop it from turning and undo the screw in the chuck in a right hand direction ( it is a left hand thread) when you have that out , still holding the shaft turn the chuck in the left hand direction ( normal thread ) and screw the chuck off
to assist in undoing the chuck do it up so that the jaws come out a bit
place something between the 3 jaws to act as a lever or use an allen key in the chuck done it tight and use that as a lever to undo the chuck
the secret is the lh thread screw in side the chuck which stops it from undoing when the drill is in reverse

look inside the center of the chuck... if the is a bold inside, remove it. then place the short side of a 3/8" allen key into the chuck and tighten the chuck... then smack the allen key from the side with a hammer the same direction as forward rotation...

Remove the left handed screw from inside the chuck and then fit the short end of a large allen key into the chuck, put the drill into 1st gear and tap the end of the allen key anti clockwise with a suitable heavy object.

Open the chuck wide open. In the center is a retaining screw, they usually have left hand threads. Remove the screw. Take an allen wrench 1/4" to 3/8" in size and fasten the short side tightly in the chuck. The chucks are usually right hand thread, so take a small hammer and strike the allen wrench to turn the chuck to the left to loosen it.

Get a large 90-degree allen wrench. It's best to use the largest allen key the drill can accommodate, at least 3/8" to 1/2". Put the short end of the allen key in the chuck and, with the long end of the allen key pointing straight up, completely tighten the chuck.

Firmly holding the drill on the edge of a table, you're going to have to hit that allen wrench with a hammer, hard. Use the flat side of a hammer to hit the allen wrench so that the blow will spin the chuck counter-clockwise. Sometimes it can take a real hard swing, so swinging through smoothly helps.

If there is a chuck bolt in the center (where the bit goes) remove it (left hand thread). The chuck is threaded onto the splindle(right hand thread). On some of those drills they have a small hole in the housing that lines up with a hole in the spindle. Put a pin punch in to lock the shaft so you can unthread the chuck. If you clamp a 3/8" allen wrench in the chuck it acts as a good handle. If there are no holes to lock the chuck, if you lay the drill on a bench and give the allen wrench a sharp blow with a rubber mallet it will unthread the chuck. If the chuck is damaged and will not hold an allen key you will have to cut the spindle off and replace the chuck and spindle.

Hope that helps

The chuck is screwed on with a normal thread, the screw in the centre (already removed) is left hand thread. Holding the drill with the open end of the chuck facing you, it should unscrew anti clockwise. It might take an impact to start it off. I normally put the gearbox to slow, set the cluth to drill and then holding the drill firmly, hit the allen key against the edge of my workbench. Bring the drill down like a hammer blow so the allen key hits the bench (which should be on your left). I find this more effective than holding the drill on the bench and hititng the allen key with a hammer as it allows for less drill movement at the point of impact.

position the drill to speed one & drill mode.u need a allen key then clamp it the chuck jaw close & tight. hit the allen key with hammer counter clockwise until its loosen. may have to do it any several times.

u need allen key that fit to the chuck. insert the short end to the chuck. tighten the chuck if u can. hold the drill at the edge of the table & smack the allen key counter clockwise. do it again if needed. but before u do it set the speed to #1 position & drill mode.thanx good luck