Case tumbler for smoothing PLA prints?

Anyone tried this or have any thoughts on how will it works, what media to use? I’ve got a Frankford Arsenal case tumbler with #5 walnut media. I’m running some prints in it right now to see if it’ll have any noticeable smooth effect, but thought someone on here might have tried this already. http://ift.tt/29wDvfI

Steppers only moving in negative direction

Hi all, I’m very new to 3D printing and have just received a Prusa i3 copy. I have set it all up and everything seems to be working normally excepting all of my steppers will only move in the negative direction as in towards to end stop. When I use the home function all axis move until they hit the stop and then won’t move from that position. I googled around a bit and I can only find people having the problem of not moving in the negative. I have already checked the polarity of the stop and stepper cables (They can only be inserted one way) but I can’t think of anything else to check. Any help would be awesome, thanks. http://ift.tt/29FuwvX