Gibb Adjustment

[rake60]

We had a problem with one of our production turret lathes at work today.

The snap ring groove in the parts checks out to be in the middle of the tolerance using
a dial caliper but it will not go through the the GO side of a Go/No Go gage.

Looking at through an eye loupe or on the comparator shows clearly that the bottom of the groove
has a sever taper on it.

The groove is very narrow so the calipers are just measuring the middle.
It measures right, but it isn't right.

I tried several things to adjust it to cut straight but it was moving all over the place.

Then I unbolted the hydraulic cylinder from the cross slide to to check the gibb adjustment.

[ame]http://www.youtube.com/watch?v=mlMW4TBJ5yw[/ame]
(I just happened to have a micro video camera in my pocket.)

Well there certainly isn't too much drag there! :

After adjusting that slop out of the gibb it cut square and fits through the idiot gages.

Then I went on to adjust all of the gibbs on those machines.
They were all that bad or worse.

Have you checked your gibbs lately?

Rick

 

[n4zou]

While waiting for a replacement centrifugal motor start switch for my lathe I did go over it cleaning and adjusting everything including the Gibbs. Only a very slight adjustment was required on the cross slid Gibb.

 

[rake60]

I doubt these had been checked in the past decade.

When the hydraulic cylinders are attached there is always pressure either in or
out on the slides.

I didn't realize just how bad they were until the cylinder rods were unbolted.

Rick