End of bar chatter. (Turning)

[mkd]

got an old (2001) kitagowa b208 chuck and get chatter while turning the OD of 1.0" bar stock but only on the last 4 parts.

3.5 oal

cnmg432.

trusty cook urethane liner

what's the solution? new chuck?

[Beem]

Try greasing it first.  A chuck can lose 25% of it's gripping power if not greased that shift.  The longer it's not greased, the more holding power it loses.  

I assume you're barfeeding, so it's rather odd that it would only be on the last 4 parts.  Insert could have been wearing as well.

[Guest]

What material....I have bars that on the ends have hardness issues.....to keep production up we took to shortening the bars by a foot on each end and held those slugs for other parts.....

[mkd]

been noticing it running some stainless muzzle brakes.

303 vs 17-4 H1100 makes no difference. ...well maybe the hard stuff resonates more..

I'll grease it up. Haven't been good keeping up on that. Light vs stiff chuck pressure doesn't seem to make much difference.

actually just been manually bar pulling 3'-4 foot sections. (no actual feeder)

thanks so far.

[mkd]

you can often see the jaws tilting during the clamp, i guess the chuck is just worn?

[Sticky]

If you aren't squirting at least a pump per shift in each jaw most of the master grease galleys are going to be plugged. Pull the chuck off, disassemble, clean, stone, clean again, and re assemble. The chuck will then feel like it has double the clamping pressure, because it will, that is the difference grease makes.

[mkd]

1 minute ago, Sticky said:

If you aren't squirting at least a pump per shift in each jaw most of the master grease galleys are going to be plugged. Pull the chuck off, disassemble, clean, stone, clean again, and re assemble. The chuck will then feel like it has double the clamping pressure, because it will, that is the difference grease makes.