Heavy-duty welding third hand - video

Heavy-duty welding third hand. By Ardo DIY. 3:50 video:

https://www.youtube.com/watch?v=ReEAN2mr_QQ

HF has 1" ball casters on sale for $1 this weekend (coupon) which is cheaper than amazon unless you want to buy dozens at a time. Should be easy to cut the case apart and then I have a ball to make this device...