How much flex with 20mm shafting for linear bearings>?

[anoel]

I used 20mm bearing and shafts on my current build and it's only a 36" x 22" and my gantry might weigh 30lbs... And while still useable... it's loose as a goose by all rigidity standards... I would highly not recommend this size rail for use... Under heavy cutting the flex will cause the whole thing to shake violently and will ruin anything resembling a surface finish.. And in center of travel there will be a signifigant droop. So you can forget accurate pockets of any size... I'm itching to build another router because I can't do the things I intended thanks to the flex in this machine...

Consider yourself warned... If you've already bought the parts, I'd suggest scaling the machine down to no more than 18" of travel with 20mm unsupported rails.

[ViperTX]

nookindustries.com in the linear shafting page under the Bearing Design Consideration , select the Application Variable....there is a deflection calculator hidden in there.