Swiveling base for sand digger

I'm in the middle of building a mobile sand digging toy, and I can't quite grasp a decent way to build a base that swivels 360 degrees. I'm building it with a 1x2 square tube holding the seat and arms and a 2" diameter round tube going from the bottom of the square to the future base. On the base, I'm not sure how to achieve a smooth swivel action. I could slide it over a 1 3/4 round tube, but I feel that would be sloppy and eventually wear down. I'm trying to avoid using a boat seat swivel, or butcher and office chair swivel. Any way I could easily incorporate bearings into this build without butchering existing technology? Bad picture for clarity. http://ift.tt/299OoZx

Submitted June 29, 2016 at 02:58AM by Mista_Bojangles http://ift.tt/292P9jj