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What's Up with These Hinges?

A project log for Raspberry Pi Powerbook

Replacing the guts of a broken Powerbook with everyone's favorite SBC

dan-jilekDan Jilek 06/18/2020 at 20:540 Comments

With the case cleaning up nicely, I've started looking at the hinges. Their unwillingness to move is what led to a lot of the damage in the first place. There are two identical hinge assemblies mirror-imaged from each other in this Powerbook.

Even after soaking in penetrating oil, these things will barely rotate with pliers on each half. Clearly this won't do. After disassembling one it appears the spring is far too tight on the shaft. Obviously it needs to create enough friction to hold the screen at whatever angle the user puts it in, but not create too much to be able to move.  These springs seem to have gotten tighter as they aged. I'm not a student of metallurgy, so I don't know what forces are at work here, and the question is academic anyways. At this point, I don't know if I should try to file out their inner diameter a little, or maybe 3D print an interference fit replacement. It'll be difficult to get the amount of friction just right, but it's probably doable.

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