Just finished the video on a chainsaw mill build that I did. I used maker pipe for the saw carriage as well as the log holders. The application for the log holders was new to me, and it took me awhile to figure out something that worked. I needed a tee connector to slide well when loosened but then also remain tight when the bolt was tightened. What worked was removing one of the friction bands.
https://youtu.be/B5qPZF5YKCg