AMECaL ST-9927 (and others) rotary dial plate repair

prusaprinters

Created as the dial on my AMECaL ST-9927 meter decided to break :(Taking it apart, and searching online, it appears to be a not rare problem. AMECaL to their credit would send parts if they had them, but since the meter is now getting on for many years old, I wasn't so lucky.Inside, there are some weak plastic tangs that locate the dial onto the mechanism, and these break off. The replacement piece fills the dial (as it has room to do so) for strength and durability.The result is a working meter, resurrected from the dead. This may fit other AMECaL meters (and those from other manufacturers who use the same dial design).There are two designs:The initial design for my meter, where I had two tangs still intact. I designed the plate around these so I didn't have to cut them. The disc is symmetrical though so came design 2The disc for fully removed tangs, cut off any remaining ones if you have any left (they may be quite brittle anyway, so worth removing), and align with the slots.Printing instructions:  Print flat, minimum of 0.2mm layer height, PLA has worked well for me for over 2 years now, but PETG if you want to give it some extra strength. Depending on your printer you may need to scale down the print, but mine fit with a good snap and no glue required. A tiny amount of silicone grease on the moving parts would not go amiss just to service the meter, along with cleaning the dial contacts with a small amount of contact cleaner or IPA, but do not get this on the plastic.BigClive does a good teardown of the meter where he shows the broken piece here: And another video showing the problem: