good start on the conveyor build .Like the idea of an inner tube with the endless belt .I made a few conveyors for my trommel last fall and used Heim joints for tension and tracking .works great ..You always push out the roller oposite side of tracking . RC4WD has some smaller sizes
https://store.rc4wd.com/Steely-M4-Ro...int_p_649.html
A few pics on my thread but can get a better shot if you would like
http://www.rctruckandconstruction.co...p?t=79&page=12