Summary i wonder, how many of u ever playing a tamiya... and how many unused spare part of it left behind... i just found my tamiya bumper roller and i tough i could make it for a balancer tools for self tightening propeller such a DJI 9450 prop or else... i need this balancing tools to reduce jello effect on my Quadcopter and basically it work like a dubro balancer... what u need is: 4 x tamiya roller like http://www.tamiya.com/english/products/94739roller_dish/index.htm and 4 x sort 4mm diameter screw... video : https://youtu.be/9kTJAQz6tDU installation instruction https://www.instructables.com/id/Balancer-Tools-for-Self-Tightening-Propeller-using/