I'm working on a project trying to combine a pantograph linkage with a four-bar linkage. I'd like to build it out of relatively at-hand materials (AKA, nothing requiring a machine shop), and I'd like to do some educational projects in the future involving students building linkages, too, so low-cost would be great. Relatively stiff and able to run unattended as a display are also desirable.
I'm thinking that bolts and nuts are going to be problematic after it runs for too long. Is there a particular type of bearing that would be easy to use/acquire? ...a good material for the rods? I have a Carvey CNC machine, so HDPE and wood are easy to machine for me. It's mostly the pivots/bearings that I'm having trouble with.