4 bar tightening

Hi, I was thinking of building a 4 bar linkage but I know that they have issues keeping together. I wanna know if there are any suggestions on keeping it all tight. Thanks!

Use bearing flats and 1-2” screws and nylocks for all the joints.

Thank you so much!

No problem. And use nylon spacers or washers, Teflon is best, in between all metal