Very nice! Thank you Christopher Howell!
You must use wire ferrules! (step 10)
Just folding the ends is not sufficient. Screws break the fine copper filaments of flexible wire if they are tightend properly thus decreasing the effective cross section area of the wire. If they are not tightend enough you'll have to little surface area contact. Ether way: Risk a fire or use ferrules!
Jens (electrical engineer)