PRO Kit. Gantry Carriage Assembly does not fit.

I am well started with my PRO 4896 kit. But I have encountered a problem when I was to install the Gantry R&P Carriage Assembly, the gap between the two steel rails are too big so the Gantry Carriage Assembly cant role on. The V Bearing Adjuster Sled is adjusted up as much as possible, and the steel rails are seated properly in the V-Con Rail Clamp. I'm pretty sure that everything is assembled correctly, so I do not understand what is wrong. I use 12X20mm steel rails instead of 1/2" x 3/4" but both Ahren and Cory from CNCRouterpart assured me that I could use them.

I am attaching a few pictures so you can see what I'm talking about

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can you loosen the bolts for the bar holders (that attach to extrusion) and push them closer together? most of the tslot nuts have some slack before they are tight, though I've seen some that self center in the slot.

Thanks for your reply unfortunately, the V-Con Clamps have some pins so they self center even without the screws are tightened. so it's not going to help.

Are the support bars flipped? they are not center drilled. Mine went on either way though.

Sorry for my late reply, on the same day Cory emailed me a solution.

I am putting his answer here as he explains it well.

Cory Kocher wrote:
I believe the issue is the setscrews are pushing the steel wide. I think the solution is two shim the upper side two bring the height down. I have attached a picture on where I would shim the steel.

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It took me no more than 5 minutes to cut some 0.8 mm steel plate to small shims and it solved the problem perfectly :cool:

So maybe a redesign of those brackets is in order. The rails should be clamped against a reference edge. If the setscrews are pushing them too far, then the edge its going to is a useless reference. Set screws from the other direction maybe?