feb 22 2011- i've finaly got it designed in a way that's compatible with a standard mendel bed. for the first printout, the holes weren't lined up exactly, so i just drilled new holes instead of printing again. otherwise, it worked great, and it was nice to see the concept come to fruition.
The .stls are now in the zip file above, and it is fully compatible, but i think there still is room for improvement. There is no method for adjustment in the case that the bearings are too far away from the rail, which will lead to backlash. the top bearing, being the load bearing element, will always rest on the rail, but the other two don't always touch. i don't know why sometimes it works great and sometimes not; perhaps it's just printing errors.
the y axis is difficult to work with since there's always something in the way of a screwdriver. here, the snap-on aspect of this design really comes in handy. i had experimented with switching places of the 0 and 90 degree bearings, so that the 90 degree bearing was closer to the bed mounting points. this puts the 0 degree bearing almost directly across from the 210 bearing, and makes it much harder to snap on, in my opinion. if someone is interest in this, i can upload those files as well, but i moved the bearings back for the current OpenY.
I'm not completely settled on the belt attachment. I think that is an area that people will change eventually, but i can't think of a better design. Another area i would change is the standard mounting points for the bed. I originally wanted to make the long arms nearly straight. i think they would print better and quicker that way, but the mounting holes don't line up. this can be done, but would require moving your y rails farther out from the center, closer to the frame corners.
I'll upload some renders and what pictures i can (though the y axis is hard to photograph) along with build instructions over the next week or two. --Buback 15:52, 24 February 2011 (UTC)