Problems printing layers and getting chewed up gears with MakerFarm's Prusa i3v 12"

[beerdart]

Does the hob bolt turn freely? Also check the hob bolt teeth for wear and flat spots.

[DrBoost]

After looking at your pictures, yeah, check the bolts. The odd pattern looks like waves in sand. That tells me it's a vibration thing, cyclical. That could be cause by lose bolts.