gaaah

Nope it's not always the battery. With a fresh battery my first copy blinks after about 15 seconds of being on. My second copy, with the same battery, can stay on for hours.

Oh, and another thing I did was grease up the collet and spindle.

OK, here's how I fixed it: There's this screw-on cap that presses the collet into a cone shaped void in the spindle. The cap was screwing all the way and bottoming out on the spindle, and the the collet showed there was plenty more space between it's kerfs to go. So what I did was just insert a small washer between the cap and the collet so that the cap can push the collet further into the cone. Works great, but I'll have the to put that little washer in a prescription bottle and in the case, otherwise I'd never remember it or find it. Also, I bought a new collet part, just to see if the problem isn't wear on the ID of the collet. A thanks to Jeff for trying.

Shouldn't a die grinder with a 1/4" collet be able to grip 6mm bits? Gee whiz, the difference in diameter is only 0.014. Yet only the Dynabrade grinder advertises that it can take both (and I can't use that because it's pneumatic, not electric). I have an old 2nd hand DeWalt 887 with a pretty worn collet. I got out in the field today and ran into a wall because it wouldn't grip a 6mm bit. Surprised. I don't know whether it's because the collet is shot or that it never could even when new.