Ditto! FINE POLE!!! They cost a bit more, but my first standard pole chuck cost me a new shop door! To explain, I was using a standard pole chuck on my surface grinder ... surfacing off a set of bolsters, and the chuck would not hold them! The flew off, took the guard off the surface grinder, and punched a coffee cup sized hole in my shop door! Had to replace the shop door, reattach the guard on the surface grinder.....and then went looking for a fine pole chuck. You can generally tell by pics....the light and dark lines you see are the magnets....standard pole chucks are spaced 1/4" or more, and fine poles are generally spaced 1/8" or less.
If you buy a new one they are way spendy! My first was a 5x10" Suburban brand, and was just under $700. I'm using one now that I got off Ebay. When you search, used the words "Fine Pole Magnetic Chuck", "Fine Pole Mag Chuck", or Fine Pole Chuck". I look a couple of days ago and saw several.