White board with white edges approximately 90 x 90 cm (check the size of trim, to make it fit) as the top plate
Paint stir-sticks from the paint department
DIY movable magazine stand
Fixing the top plate
First, I drilled a few screw holes in the KALLAX to attach the top plate.
I drilled 4 holes (blue dots in drawing below) as close to the vertical wall as I could. (refer to 1)
The drawing above shows drill holes for one KALLAX unit
The two center holes (pink dots) have more or less no supporting material on the inside. So, I made the hole large enough for a screw head to come through on the inner side. (refer to 2)
Once I completed the drilling, I was ready to attach the top plate (white board).
I found it easiest to lay the top plate (white board) on the floor. Then, position the two KALLAX units (back to back) on the top plate.
After that, I measured carefully so that the KALLAX units would end up at equal distances from the edge on all sides. (as evenly as possible).
There is a slight height difference between the vertical walls and the top and bottom panels. So I cut paint stir-sticks into approximately 5 cm long pieces, drilled a hole through the centre and placed them between the gap to compensate for the height difference.
After checking that all positions and levels were right, I screwed the KALLAX units to the top plate. I left as small a gap between the two back-to-back KALLAX units as possible.
Installing the bottom plate
Then I put the bottom plate (plywood) on top of the two KALLAX units and centered it the best I could.
I wanted the wheels to be as invisible as possible, so I positioned them as far inwards as I could.
I pre-marked with an awl where the wheels would sit.
Then I pre-drilled with a small drill and screwed long screws through the wheel mount, plywood and into the KALLAX unit.