[Andrebr]

What do you think is better: use a 1 inch thickness aluminum plate with no reinforcement, or use 3/4'' plate with that lateral reinforcement (even it saving 1 kg on each side)?

Obs: I will glue it with epoxy as the gantry.

[ger21]

With the V Bearings you are using, it doesn't matter. The bearings will allow more movement than the gantry sides.

[Andrebr]

straightness tolerances as tight as +/- 0.001 in. for v-rollers according to BWC.

[awerby]

That spec doesn't mean that every implementation using those rails and wheels will be restricted to +/- .001" movement at all points. That's determined by the structure of whatever you're attaching to them. The weakest links in your system will cause the most flex. Those are not likely to be the 1-inch thick aluminum gantry plates, as Ger points out.