Let me start off by saying that I really stink at doing things by eye. What other people look at and align or cut or mark or whatever freehand and eyeballed, I will mess up reliably. I need jigs and guides to mistake-proof my my builds. So, that said... Has anyone got tried and proven methods of assuring that the motor tubes in a cluster are parallel? Introducing a radial cant is a good way of introducing spin if spin is what you want, but I want tubes dead parallel. Please start with methods that you've used or seen used before inevitably going off into brainstorming new ideas.