How to properly Mount Flanged Linear bearing on my Printbed ?

Hi All,

I am making a custom 3d printer and have bought a 4 mm sheet Aluminum metal 20 - 20 cm and these flanged bearings:
[www.robotdigg.com]
I am using this nema 23 Motor for it : (A bit overkill but future proof i guess..)
[www.robotdigg.com]

Now my question is. how do I mount it on my heatbed.
Shall I do 2 - 8 mm holes and one 10 - 12 mm hole and attach these bearings and pom nut on top of the plate with using there screw holes.

Or shall I do 2 - 15 mm hole and one 16 mm hole and pass insert the bearings in the sheet metal and use the holes to secure them.

Problem now with second option is that I am not able to find a machinist here who can drill those large holes. That is (15 mm and 16 mm).

Also Will 8 mm rods be strong enough for z axis ?

Edited 3 time(s). Last edit at 03/03/2016 11:39PM by Angel_Wing.

Is this sheet of aluminium the heatbed ?
i would not mount this directly to youre heatbed because 1. you will lose heat to the bearings and rods 2. aluminium (and the steel bearings/rods ) will expand when hot
And how do you level youre heatbed ?

Hi Michel
Thanks for replying. No it will not be what the extruder will print on . I will add an etched PCB with glass on top of it to make for complete heated bed. Currently I am making it light by removing excess metal. As can be seen in attachment. Now back to first question.. how to attach bearings to it??

Edited 1 time(s). Last edit at 03/02/2016 12:35PM by Angel_Wing.