Large Delta printer build - advice and suggestions welcome

[curious aardvark]

honestly the linear rails will make absolutely no difference whatsoever on a delta.
A 4 wheel carriage, properly fitted, will run smoother and faster with less potential vibration.
As far as belts go - get decent ones but also use a tension based belt tensioner.
They look like the middle of a cloths peg.
Bascially they keep the belts at exactly the same tension, no matter what.
One of the first things I did to my delta was add 2 to each belt.
It also means you don't need complicated belt tensioning apparatus. https://www.amazon.co.uk/HALJIA-Timi...gateway&sr=8-5

One thing you probably haven't considered is a kit from this chap. They'd used one on the duet3d stand at tct this week.
http://www.zatsit.fr/english-summary.html
Dunno if you can buy them yet or not, the guy who builds the duet machines is a certified mechanical genius. So he probably got some ahead of the launch.
But worth considering. On checking the kickstarter. It's a full delta kit and hasn't started shipping the kickstarter items yet.
So worth a look, but it woupd need to be a diy setup. Magnets and carbonfibre rods probably a better bet.

Unless i missed something and you're using the linears for the arms - I can see that working, lol

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Oh yeah (puts his mod hat on), autowiz and trakyan - play nice, there's a couple of good lads :-)