Can't tighten compound gib anymore!

[kdoney]

I have tightened it as much as I dare. I can barely move the compound but it still has a movement up and down. The compound is solidly in contact with the cross slide and the new 4 bolt mount is working as expected. I have extended the lever with the new QCTP but with the light cuts I'm taking in aluminum, I shouldn't be seeing any movement of the compound.

This is a 9X20 Grizzly.

[HuFlungDung]

Is this gib adjusted with setscrews (the cheap way), or with a full length tapered gib which adjusts via push screws at the ends?

Supposing that it is the former, you could have one setscrew creating drag pressure on one portion of the gib, while the others are too slack. The best way, IMO, to make a solid feeling slideway with that type of gib is to shim behind it with brass shimstock. You should be able to find a combination of shims that will be within .001 of being perfect. Then, you don't need to rely on the uncertainty of tightening and locking all the adjustment setscrews perfectly equally. You will still need them in there to keep the gib from falling out. Drill through the shimstock so the setscrews can engage the dimple in the back of the gib.

[kdoney]

Thanks, I'll give it a try. This is the strangest looking gib I've seen. It is not shaped like a gib. It is a simple rectanglular piece of metal with the edges knocked down.

[acondit]

Kdoney,

Have you checked the screws that fasten the compound to the protractor plate?
The protractor plate is what is held down by the 4 bolt clamp. If those three screws come loose you will get lift on the compound unrelated to the tightness of the gib.

I have thought about drilling two more holes between the original three adjustment screws to make the adjustment more effective.

There are also pins inside the compound adjusting holes that are pushed into the gib by the adjusting screws. Make sure that they haven't gotten lost. The screws won't screw in far enough to contact the gib, just far enough to push the pins in.

Alan