The standard plastic printrbot base allows the z-motor to rock - this one doesn't.
Optionally you can also use linear bearing clamps instead of zip-ties to hold the y-bearings in place.
My tested clamps have 4 holes for screws. I've added other two holes to this version. This is not because you need 6 but because you have the choice to use fewer - 2 may be enough but I haven't tested this.
The zip-tie slots are still there if you want them.
Also the motor has been moved 0.5mm to match the spacing between the traveling Z-nut and smooth rod.
And there is more.
There are holes you can tap for screws which lock the smooth rod.
There are also some mounting holes to screw the base down if you want too.
The Y motor works fine the way it is but I'll probably add support because I can.
Z+Y is working.
There is a problem with spanner access. I've enlarged the hole in the CAD file but I'm not sure how well it will work.
The test print is printed at .1mm and there is no real sign of ripple in it.
I wanted to print this in .2 layers but slic3r made a mess of the perimeters around the small holes. Tweaking the settings or using a different slicer might fix that but I just print it at .4mm
The 2.6mm holes are meant to be tapped to M3.
If you use the clamps and you have screws over the threaded rods they need to be short.
If you over-tighten the clamp screws you will warp the flat part of the base.
There is very little clearance between the clamp and the underside of my hotbed mount screw.
I glued my Y limit switch in place and I found I no longer needed the Y adjuster screw.
The motor bracing has a slot for the 5/16 nut but you generally have to screw that on as you slide the base/mount in place - if you slide the mount on without the nut you are unlikely to be able to get the nut on later.
The Z+Y base.
Mine was printed in ABS at .3mm
Spanner access was a problem and the access is improved but may still be a problem. Make sure you slide it on with the 4 nuts in place and don't forget to include the ZEST part if you are using it here.
You should use my taller Y-bearing mounts. You don't want them to actually touch the motor so they are meant to be a fraction of a mm too short to touch. The Y belt needs to be raised. I raised mine 4mm but because my based printed out of square another couple of mm are needed.
I used a washer on either side of the bearings but other configurations may work.
This is no problem if you use the standard Y clips but it is a CAD and print job for my belt posts.