L-shaped plywood reinforcement

Check the pictures of the Rostock prototype and you'll notice that there is an L-shaped plywood reinforcement at the back of the printer. There is also a similar reinforcement structure used for the Delta-Pi. The Kossel Mini does not need this reinforcement because it is, well... mini, and in fact Johann C. Rocholl hints at this in the RepRap.org wiki page for the Rostock:

A shorter printer may be more rigid / stable and may not need the extra plywood frame on the back and side.

Yesterday I went to buy the wood to reinforce the Delta Steel prototype (which by the way is slightly taller than both the Rostock and the Delta-Pi prototypes), and 15 wood screws later this is what I got:

As can be seen in the picture above, I also got started on one of the belts but didn't tighten it as I was just checking the alignment of the pulleys and through-holes. Everything seems fine at this point so the next step is to route the three belts and tighten them. I am using approximately 195cm of 6mm GT2 belt per column here.

Edit: after tightening the belt and trimming the excess length, I have calculated that I am using approximately 188cm of 6mm GT2 belt per column or 5.64m total.

For the reinforcement structure I am using two wood pieces, the wider one is 16mm MDF like the top and bottom plates, the narrower one is 10mm plywood, as well as 15 x 3x40mm wood screws. The dimensions of the wood pieces are:

• MDF: 840 x 200 x 16mm.
• Plywood: 840 x 150 x 10mm.

They are screwed together and to the back right corner of the bottom and top plates to form an L-shaped reinforcement that prevents the printer "tower" from leaning in any direction.

Ugly? Yes indeed. Functional? Absolutely!