Whats the next step up from LMU88 Linear bearings {upgrade}?

So my prusa i3 has some really cheap bearings and they don't fit flush on the 8mm rod. They wiggle back and forth. The heat bed wiggles and so does the extruder body. I want to make the printer as sturdier and accurate as possible. I'm going to get a p3steel frame laser cut soon to fix most of the stability issues with the frame. But that wont fix the problems with the y and x axis from wiggling. I saw somewhere some people use bronze bushings. Are those any good. I also hate that the lmu88 bearings bore grooves into the rods. And I do not have harden steal rods just normal Chinese ones. I looked into extrusion rods but i'm not handy with cad and I cant find anything that will make the prusa i3 support extrusion rod linear motion. I just really want a better alternative.

Interesting read with lots of options:
[forums.reprap.org]

-Olaf

If your budget allows, this type of thing is about the best you can get: [www.ebay.com]

I have linear guides in X and Y axes and there is no detectable play at all.

If you want to stick with linear shafts I think misumi is a good choice.

Their LMU8 bearing is only 6$. I'd recommend getting matching shafts as well since getting optimal performance relies on a fairly close tolerance between the bearings and shaft. For more rigidity I'd consider moving to 12-16mm hollow shaft to keep the weight down.

Obviously the nuclear solution is to go to linear block and rail which is roughly two orders of magnitude more accurate and rigid than any shaft-based solution. Getting the advertised performance requires that it is mounted to a (flawless) flat surface though.

Once you move past the absolute cheapest components, frame design will be the limiting factor. A few microns of play in the linear motion is nothing compared to bending of the frame.

Thanks guys. Since I was already going to get a p3steel it will be an extremely sturdy frame. Probably the sturdiest frame out there. I have seen those rails on some 3d printers and they look promising. Do you have any links to mount them so I have an idea how to mount them? I'm really bad with cad so its very hard for me to make a part for it.

Linear guides have holes drilled in them at regular intervals. They normally drill them for cap screws, but you can use any screw with a head and lock washer that will fit. All you need is a flat surface to screw them down.

If you're doing 3D printing, it's time for you to get better with CAD- only printing other peoples' stuff gets old, fast. Start by modeling the rail and bearing block that you will get/have. Then add the rest of the stuff.