Kurt D688 Thrust Bearing destruction... What happened??

So its about time to throw some more rebuild kits into some vises.. Got a screaming
deal on E-bay. qty 10 D688 rebuild kits for $110.

Did a few a couple of weeks ago, and did 2 this afternoon, and hit the 3rd one today..

The first 4 I did. Nothing surprising, they actually looked pretty good, to the point where
I could clean up the bearings and the thrust washers and they would at least be serviceable.
More grit than bad bearings it seemed.

The last one. What a mess.. The thrust bearing had to be cut since it got hung up on the
c-clip (or whatever kind of windy clip that is) groove.. But there were no bearings left,
and the 2 thrust washers on either side of it were missing pieces... And the grease was
really "solid" almost like it had gotten really really hot..

What happened???? What did I do??? All these vises were all bought new, and are approximately
the same age, with roughly the same amount of use/abuse.

Top left and top right.. Vise 1 and vise 2 from today.. Bottom.. The last vise.. The thrust
washers with pieces missing were the ones in direct contact with what was left of the bearing..
And remember, no bearings in the thrust bearing, but it was round(ish), I just had to cut it to get
over the c-clip groove.

Someone dropped one of ours on the floor to cause the damage shown in the lower row of bearings.

Might it have got enough coolant in it to wash some of the grease out and encourage corrosion? Do they ever get re-greased in use (don't know what Kurts have, but my oriental clones have lubrication points).

Looks real similar to what to my Kurt looked like after about 3 years of every day use. Bought 2 at the same time and the other one no problems.

I just assumed I had worked it to death! No real explanation, just shit happens.

Do you ever use a mallet to get that extra oomph out of the vise? I used to ... and dealt with thrust bearing failure like that.

Can be caused by a small piece of metal shaving in the bearing. If one of the rollers gets jammed it will quickly ruin the bearing.

Bob E said:

Do you ever use a mallet to get that extra oomph out of the vise? I used to ... and dealt with thrust bearing failure like that.

Click to expand...

Only once the thrust bearings are already mis-behaving.

Possibly it was over torqued or was an impact wrench used on it?