Wheeled clamp. By create. 2:42 video:
https://www.youtube.com/watch?v=dZFruJITY2w
Previously:
https://www.homemadetools.net/forum/...019#post140836
https://www.homemadetools.net/forum/...827#post140326
https://www.homemadetools.net/forum/...886#post137367
https://www.homemadetools.net/forum/...8400#post87451