X-axis Edge-Pully parts for PRN3D

http://bunkai.sakura.ne.jp/bunkai-wp/3d_printer/572/

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Is PRN3D exclusive parts.
Rigidity against the tension of the belt is a shortage in the X-axis of the pulley standard, it may not maintain the horizontal pulley. By replacing with the edge pulley, to ensure the grounding to the body, to maintain the horizontal even whe