I have the same issue with mine. Haven't used it since I got it to the house,. But I did use it over at my father in laws house when I was building the sub frame for my loader. Darn chuck would randomly fall out when it got warm.
Can you run me though how you fixed yours?
Mine is also made in Taiwan. Not sure of the age. Pops got it from a friend of his who found it in an estate sale for $50. Figure the old lady who was getting rid of it didn't know what it was worth.[/QUOTE
The chuck has a Morse taper (male) and the spindle has a female morse taper and Oriental machining is on the corse side and unlike Lil Foot and myself, you most likely don't have the machinery to regrind the internal taper but... here is what you can do.
Get some emery cloth (not sandpaper) and carefully smooth the female taper in the spindle with it running at slow speed to get the coarse machining ridges out and then look at the male taper and smooth that as well.
Clean both tapers with a clean cloth and acetone so both are squeaky clean and then take some 271 Threadlocker and apply it to the male taper.
Insert the chuck (and male taper) in the quill and with a block of wood on the end of the drill chuck, smack the wood with a mallet a couple times. The, let it sit for a day. It won't come out again. Did that before on a cheap drill press. Chuck has never experienced 'fall out' again.
Hope that helps and be careful with the spinning quill and the emery cloth