Quote Originally Posted by ger21 View Post
It's your money.

My point is that if the machine frame was strong enough, you could literally hang a car off of the 20mm rails, and be well under their load limit. your machine will be operating at about 5% of the rated load limits of 20mm rails. If you want to spend a little more, feel free. But there will be zero noticeable difference.

There wouldn't be any difference between 15mm and 25mm rails, on a DIY machine.
I read a post one time of someone having issues with the hardware for the holes in the rails , as there were certain sizes , and one worked better than the other with extrusion. But I think the holes are the same diameter , so I'd have to check that out . If everyone is against using 25mm guide rail , I'll certainly consider going with 20mm .

Guys , is there a recommended carriage you can buy for the Z axis that fits a 100mm spindle that is ready to be bolted up to the X axis plate? I don't really want to build that and would prefer to buy a complete one .