Is my cross slide gib strip not ground properly?

it is very possible the thickness is the culprit. You need to check the dovetails male and female to know what your dealing with. Without the top installed place the gibb on the cross slide does it rock in the dovetail or are the dovetails correctly matting?
I wouldn’t rush getting a surface grinder for this job. You don’t want to rush purchasing a SG and it’s not cut and dry grinding a thin gibb like you have. Without coolant know how and some talent it would be more warped than what you started. Believe me I’ve been dabbling in the subject of grinding thin metal and it’s not easy and just happens going through the steps.
Get some measurements and map it out to see what you have then come up with the best solution.
 
Thanks. I will do that, most likely tomorrow- if I can find some dowel pins.

FYI, the pic of the cross slide I posted earlier is not mine, it was just to clear up the terminology.
 
if you had the inclination, you could lap the gib flat on the offending side.
simply dunk a sheet of 150 grit wet/dry sandpaper in water and put it on a sheet of plate glass.
be careful to not add too much pressure while lapping, the metal should come off rapidly.
clean the gib meticulously with alcohol or acetone to remove sand, grit, etc.

scraping would be another method :)
 
I know leadscrew was mentioned briefly, but I would look very close at it and the nut for rust, dirt, damage and alignment. Seems much more likely.
 
Have you tried bluing the surfaces, looking for high spots? Clean the oil off all the surfaces and use a magic marker to coat the surfaces. As you move the mating parts, the coating will rub off the high spots.

If you have eliminated issues with the lead screw and you are experiencing problems at only one place, I would suspect that the problem is due to a non parallel condition of the dovetails with either the cross feed or the cross feed saddle or both. Measurement with dowel pins as previously described should show which.

A gib of this type should be a loose fit. The set screws make the clearance adjustment. The sliding surface needs to be flat but the back surface should be a non-contact surface so curving or a taper shouldn't be an issue. If you find that you have a binding situation the back side can be thinned down by filing or lapping. Presumably, you are only looking at a few thousandths at most.
 
Ulma Doctor said:
if you had the inclination, you could lap the gib flat on the offending side.
simply dunk a sheet of 150 grit wet/dry sandpaper in water and put it on a sheet of plate glass.
be careful to not add too much pressure while lapping, the metal should come off rapidly.
clean the gib meticulously with alcohol or acetone to remove sand, grit, etc.

scraping would be another method :)
Click to expand...

How will this remove a taper though? Let me illustrate my question with my MS Paint skills:

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If I flip the taper side down on top of a sand paper, apply even pressure and sand it, it will simply keep removing the same amount of material across the entire length i.e. the taper will still be there the same amount but the gib will get thinner overall.

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This is where it has to be ground flat on something like a surface grinder.
 
If you apply pressure to the thick end, the thin end will float and the bulk of the material will be removed from the thick end. Take frequent measurements and don't take off more than is necessary. A few thousandths should do it.
 
I did have a few mins last night and managed to find some dowel pins. Before anyone asks, the micrometer body was interfering with the measurement that's why I used the calipers. So the carriage side is dead on parallel:

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The cross slide side had a .006" variance but it was hard to measure so I need to redo it when I have some more time. But again, I wouldn't know how to fix this issue of removing the .006" from the back. If I remove it from the gib at least it won't stick and I can do the adjustment by the set screws. Remember that it sticks even with the set screws completely out.

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RJSakowski said:
If you apply pressure to the thick end, the thin end will float and the bulk of the material will be removed from the thick end. Take frequent measurements and don't take off more than is necessary. A few thousandths should do it.
Click to expand...

In the absence of a surface grinder I'm thinking of creating a fixture and using it with the belt sander. The idea is that the gib will be captive in a slot (so it can't move up or down) but allowed to move side ways. I will put this jig against the belt vertically and simply pull the gib across the belt taking a light pass or two.

Here's the slot I made the gib sits flush on the thinner side but starts to protrude up where it's thick, as it's pulled across.

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Another question, are gibs of this sort hardened? I'm wondering if I can just mill it. I can make a magnetic fixture of some sort and just mill it flat.
 
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