Is it better to have bearing flats on your dr4b joints as shown below or just screw then in directly? 
Always use a bearing on something that moves. Only exception would be a gear/sprocket moving on a screw. Also, given your picture above, you can eliminate the bearing on the upright by locking the screw in place using a nut(s).
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Ok thanks
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If the joint is carrying a lot of load, I would use bearings. If it is not, then a screw with a washer on each side and in the middle is enough.
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the bearing makes it so the screw goes through the center of the hole and reduces a lot of slop so I think doing bearings on all joints is worth it if you have room
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Bearings also keep the metal around the holes from getting damaged. This is less of a problem with steel, but aluminum starts to disappear quickly once a load bearing screw thread is twisting around inside of it
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I’m looking back at this thread and realizing how braindead I must have been to even ask this…
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Looking again at that picture, my teams do a combination of both. We lock the screw to one side of the joint, only using bearings on the side that moves around the screw. If that makes sense to you.
Always use single bearing screw joints when possible.
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