Help in adjusting gibs

[Frank Ford]

I've been planning to tune up my mill - it's a Bridgeport clone (Sharp) I bought new about a decade ago, so it's a low-mileage machine in generally fine shape. In particular I'd like to get some detailed instructions and/or tips on adjusting the table gibs - knee, too, I suppose.

Jeez, just after posting this, I realized I hadn't really searched for info, so if it's appropriate, just point me toward some items. Hobby Machinist has so many sub forums I find myself routinely looking only at a couple - general and accessories. . .

 

[morph]

Frank,
not sure if this will help but here you go.
http://its.fvtc.edu/MachShop3/BasicMill/millmaint.htm

 

[Richard King]

The pictures are showing how to adjust a gib on a column of a vertical machining center (VMC) that I used as a project in a scraping class I taught. The same principle can be used on all machines and all gibs. Use a mag base with indicator mounted on one side of the machine. On this one mount the mag base on bottom 1/2 the column and put the indicator on the head then push and pull the part with the indicator and screw in the gib so you have from .0005" to .001" slop. You have to check the "lost motion". When you push and pull you can bend the castings a little.

So you push it and release remember the reading, pull it and release it. The lost motion is the amount after you release it. On some worn machines you have to have it looser because if you adjust it in a worn area it might bind up on the unworn areas. Like the top of the knee on your mill, it's worn in the center and not the ends. We check both sides of the gib when we are scraping the taper. If the taper is the same on both ends, it will have the same lost motion on both ends. The gib has to be left open a little so the oil can lubricate both sides of the way. On big machines I use a pry bar to move the parts if I can't do it by hand.

 

[4GSR]

Richard,

You have taught these people very well. They are clean, neat at what they do.

You see it in the equipment that come from their part of the World.

Just wish I was as skinny as they are!!!

Ken

 

[Erik Brewster]

After taking Richard's class, I went home and tried his suggestion of 0.0005" - 0.001". It worked very well for me on my mill.