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Brian, by the sound of it this will be your first time taking the chuck apart to clean it. If that's the case there's a pretty good chance that when it goes back together that it'll be just fine. But if it's still out you might try the trick I used to check the jaws for bell mouthing.
I took a piece of larger size drill rod and just lightly pinched it in the jaws. But any consistent size shafting would work. I think I used my piece of 7/8" which is still around 2ft long. Then with an indicator on it I pushed it firmly away, released it and noted the reading. Then I pulled to me firmly, released it and noted the change. With the indicator about 6 or 7 inches out from the jaws I was getting something like .005 or .006" of non springing travel.
I repeated this at a few rotational positions and it didn't get any better. Compounding this was my ability to poke a .003'ish shim between one jaw and the shaft when pulled for clearance. It wasn't much of a poke due to the rounding of the jaw's edge but it did fit at the nose of the jaws where back by the face of the body I couldn't even start it. Another indication of some bell mouth wear.
If I tighten the chuck it holds fine without the ability to fit a shim. So it still makes good parts but clearly from what I can see I've got a few thou wear overall.
As for how to grind it I've got a couple of options. One is a 1/4" size angle grinder I bought many years ago. Another is my old cheapie Foredom clone that has a handpiece diameter that would fit my larger size boring bar holder (currently the winning idea that I only discovered would work about 3 months ago but still need to "get a round tuit"). And yet another option that I've looked at for a while which I'd be able to use for a few things around here is one of the low cost CNC spindles like THIS ONE that is only $130C for the spindle, power supply, mounting bracket and collet set.
I took a piece of larger size drill rod and just lightly pinched it in the jaws. But any consistent size shafting would work. I think I used my piece of 7/8" which is still around 2ft long. Then with an indicator on it I pushed it firmly away, released it and noted the reading. Then I pulled to me firmly, released it and noted the change. With the indicator about 6 or 7 inches out from the jaws I was getting something like .005 or .006" of non springing travel.
I repeated this at a few rotational positions and it didn't get any better. Compounding this was my ability to poke a .003'ish shim between one jaw and the shaft when pulled for clearance. It wasn't much of a poke due to the rounding of the jaw's edge but it did fit at the nose of the jaws where back by the face of the body I couldn't even start it. Another indication of some bell mouth wear.
If I tighten the chuck it holds fine without the ability to fit a shim. So it still makes good parts but clearly from what I can see I've got a few thou wear overall.
As for how to grind it I've got a couple of options. One is a 1/4" size angle grinder I bought many years ago. Another is my old cheapie Foredom clone that has a handpiece diameter that would fit my larger size boring bar holder (currently the winning idea that I only discovered would work about 3 months ago but still need to "get a round tuit"). And yet another option that I've looked at for a while which I'd be able to use for a few things around here is one of the low cost CNC spindles like THIS ONE that is only $130C for the spindle, power supply, mounting bracket and collet set.
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