After 9 weeks it arrived and found out why it was so cheap: crappy product with a main wheel that was drilled out of centre and the bushings had a large slack. My first bend made all kinds of radii in one pass, but not the right one.
At work we have a lathe, so I took de darn thing apart, turned new bushings and centered the main wheel. After rebuilding it works fine, but to those who have not the acces to rebuilding tools: Think before buying.

"If things are that cheap, it probably has a reason."
Herman