When drilling out a stump w/ a probably too big 2 9/16" self feed bit w/ a Milwaukee 1663-20 spade bit got stuck! When trying to reverse out chuck screw broke! My Makita 6302H(0-550rpm) broke it's chuch screw too and so did the Ryobi D-130VRRK Right Angle(0-380)! A long pipe through a 7/16 inch wrench broke it free! Anyway I can get chuck screws for the 1663-20 and Makita 6302H. I cheated on the Ryobi and used the M6 x22screw the Makita uses as the M6x 25mm is obsolete!I recently scored a mint Porter Cable 6614 on Ebay and guess what it chuck screw is obsolete(didn't break it-yet anyway). Is there a source for these sxcrews? I got the 1/4 X 1 inch 1663 screws and the M6x22mm Makita 6203H sxcrews from ereplacement parts. I learnt my lesson and will use my Milwaukee 9072 impact wrench or a long pipe to break stuck bits free. And yes I know thye Big Makita DS4000 uses a morse taper chuck!