Can We Talk About Gibs?

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Hukshawn

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when I made that back plate for the 4 jaw chuck, I had enough movement in the compound to annoy me. I had to put the compound at o degrees and move it closer to one side (far enough off centre) to get close enough to work on the plate. Because of the interrupted cut for the first while I had to really tighten the gib to stop the .010"~ play. Which eliminated the use of the compound side as it was too tight... I loosened it off since to use it but its still somewhat stiff. I haven't tried again to dial it in again yet. there is still some lack of rigity there. There's still movement. We're not talking about tons of movement but enough to annoy me. Especially if I'm cutting an internal thread (which I've been doing a lot lately. Made 3 spindle threaded pieces for various projects so far)
The last time I tried to fine adjust it I was unsatisfied. There's a very very fine line between rigity and smooth movement, and I haven't quite acquired it.
What can I try aside from the back and forth of adjusting the screws?

I should note. The gib is about 1/8" - 3/16" thick and there are 4 adjustment screws. There is no damage in the dovetail or gib
 
I took some pictures to show the setup, it wasn't until I turned everything around I realized the gib is NOT seated well at all... never noticed that before... don't like that at all, I'm sure that has created huge amounts of unwanted wear on that dovetail.
How can I seat that better??

IMAG0817.jpg
IMAG0816.jpg

Edit... I figured out how to embed my photos instead of just attaching them. That should make it easier to view them without having to open the image.
 
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Shawn, it might be the camera angle but are those screws hitting the gibs above the gib centerline? If so, then they will cock the gib like they seem to be.

First, remove the gib and clean it really well. Make sure there is no damage to the gib.

Is there something between the gib screws and the gib? If so, what is it? If not, then I would suggest you use make some very short rods with an angle on the gib end to match the dovetail angle on one end and a flat on the other end to contact the screw. Make three and use a ball bearing for the screw you use for a gib lock. This gives much broader contact for the adjusting screws without chewing up the gib itself. The ball bearing allows point contact when locking the gib.

Once you have those inserts in place, adjust them. I would suggest you adjust from the inside, out. Loosen all screws, then bring a center screw into contact plus, say, 1/8 turn. Do the other center screw and do the same thing, working out to the ends. Then try it and see. Adjust until the compound moves smoothly but without play.
 
I get the idea behind the angled plug. I have some brass I could use. But maybe I read this wrong, I'm not visualizing where the ball bearing goes...
 
It replaces one of the angled plugs.
 
The bigger screw for locking the slide should probably be in one of the middle two holes, their may be a bigger recess in the gib strip that shows which hole it went in originally.

Stuart
 
I think the big screw is because someone broke s set screw or stripped the hole
 
Mike, is the bearing thing kind of either use the brass plugs or bearings, one or the other? Or is there a purpose to use plugs and bearings here or there?
 
Put the bearing in one of the center holes. It is just a way to lock the gib.
 
I agree with mikey on the screw holes being too high preventing the gib to bear correctly on the dovetail. The gib really needs to be thicker to fill up most of the gap in the slide assembly. Last, if I had to guess, the compound needs to be rescraped and fitted to get the bearing surfaces of the dovetails bearing properly, along with making a new gib. This would help on keeping the slide from creeping on you too.
 
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