I cut two pieces of (roughly) the same lenght from 50mm wide 2mm thick aluminium, put them together and drilled one 3mm hole for the motor mount. Bolted them together from that hole and drilled the remaining holes with drill press. Exact hole positions are vital, so atleast caliper must be used. The mesh adjustment hole was made from series of 3mm holes which were opened with dremel and the hole for the motor axle was made from two 10mm holes. The hole from where the transmission case comes through is quite snug fit, so it doesn't allow any slack or twisting which might strip the screws from transmission case.
The final rounded shape was made with belt grinder, with pieces still bolted together.
First I thought that I'd polish the final piece, but I ended up spraying it with black paint (I'm lazy...).
All the tools needed are available at the place I work, so you could say I'm fortunate. Ofcourse, no workingtime was spend while making this...
