Mounting 5c Collect Chuck - Help!

[BobWarfield]

A couple of thoughts...

The chuck will go on more than one way relative to its bolts. Try each of the positions until you find the one that gives minimal runout. FWIW, I marked each postion on my lathe's spindle and each position on each chuck after doing this with just some automatic centerpunch pips: 1, 2, and 3 pips. Now I can always reinstall the chucks for minimal runout and in the same position.

With that said, I doubt it will fix your whole runout problem, or even likely the majority of it.

These things are kind of hard to diagnose remotely. You're going to need to get out your DTI and start sweeping until you find what is out. As I mention, my chuck's outer ground surface is WAY out when it is running true. Ignore the outer surface. Instead, start from the spindle and work your way out until you sweep the indicator and find the problem.

For example, remove the chuck and its backplate and sweep the spindle's spigot that mates with your backplate. Then check the backplate, then you are back to the chuck.

How did you attack the chuck to its backplate? In my case I used a shrink fit, which is very tight and has no clearance. If you just bolted yours up, perhaps there is some leeway there that's working against you. Make sure there is no chip caught anywhere too.

Let us know what else you learn. Hard to tell at this stage just what went wrong.

Best,

BW

[Ziuck]

After messing around and beating on this damn chuck so much I think my spindle bearing is jacked up!

When I put on my 5" Bison chuck I get weird runouts when spinning it.

Does anyone know what aftermarket bearings fit? Also is the bearing press fit onto the spindle?

[sansbury]

How much beating are we talking about here? A few taps with a rubber mallet shouldn't cause bearing damage. It is certainly possible to damage them if you start whacking at it with a claw hammer but it's not the first thing I'd suspect.

1. Have you used the lathe for a while before you tried mounting this chuck? Were there any problems then?

2. Before you tried mounting this chuck, how sure are you that the spindle runout was good? Are you sure you're not just seeing something that was always there?

3. If you undo the belt and disengage any drive/threading gears, and spin it by hand, does it turn smoothly all the way around? Do you feel or hear any clicking sounds that weren't there before?

4. If you're using an indicator, are you indicating the spindle mouth or some other fixed, known-good location? Are you sure you're measuring it properly, indicator is firmly mounted, etc.? There could just be a problem with the chuck mounting, including something silly like a chip stuck somewhere.

[Ziuck]

I took the spindle out last night and re lubed the bearing on the bed side. All is well now. I would spin it and it was smooth but would "drop" at times when a chuck was mounted. I am not sure what had happened.

My run out with an indicator on the spindle is ~< 0.0005"

No I never did beat on it with a claw hammer! only light tapes on the chucks with a rubber mallet.

I think I've come to the conclusion that this 5C chuck is crap and does not mount the precision bar true. It get's skewed.

I can mount a 12" bar on my bison 5" and it is only ~0.003" out at the end.