Belt drive vs direct coupling pro's and cons, Poll

[Zeeflyboy]

It was done long ago to eliminate vibration when drives were crappy. Now drives are digital so that will not matter so much. Now is done for the sake of hiding the motor, gearing it and so on. And yeah, for the sake of alignment and simplicity, as 2 things bolted to the same plate/plane is easier to align than 2 thing bolted on a same axis.

Anyway i don't like spring couplings and having in mind the cheap price of ball screw mounts, i would always use both sides angular contact bearings. The so called rigid mounting, or scenario D.

At the end of the day machines look more tidy and all is more rigid when you don't see the motors. Protruding motors will need a good mount, not just 4 bolts and spacers, so its up to you.

Angular bearings on both sides!? Am I misunderstanding what you said here and you actually mean one set of back to back angular bearings on one end and a floating bearing on the other or are you actually suggesting angular contacts on both ends (fixed/fixed)?

I don't personally think fixed/fixed is a good idea in general unless you really need that increase in critical speed, but especially so on machines built from aluminium extrusion like Desert's due to the difference in thermal expansion between steel and aluminium.

Re the topic, If you use proper high torque belts (bearing boys is a good source of HTD belts) then slip is a non issue. Theoretically you might have a bit less accuracy due to belt flex and a teeny tiny extra backlash but in reality I don't think it's an issue on a hobby level machine... they are pretty much backlash free and the re-inforcement strands mean that flex is very minimal.

Personally for me I prefer direct with decent couplings, but it's really just a question of what better suits your machine design I think.