Summary

A box for long breadboard (17x6 cm).

Instructions

This data will be probably useless without few changes, because every laser has a different thicknes of cut and every matherial is a quite different too, even when documentation says something else;).

So, at first is good to do some tests of joints in your vector editor.
Because there is no other chance to check laser cutted line thickness.
Make a one shape with pins and second with holes with same size.
Use the "transform each" function to make a different sizes of every pins. And make the variations of the part with pins.
Change the size for 102%, 104% 106% etc...
Send it to the laser to find the best tight joint.
Then use this scales of the pins and holes for whole project.

Assembling:
When you done everything good you won't need to glue the parts of box together.
To join the breadboard to box is good to use cable ties or 3M dual lock.

PS:Thank to FabLab Rotterdam staff with help.

box for breadboard & arduino (with laser cut)