Update 15-11-2022:
Added version without built-in support, for printing with SLA, for experimenting wit different supports, or for easier remixing.
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Inspired by the “Flair 58 Plunger Piston Alignment Tool” by bykim, and not a remix, because not a single polygon is shared between the two models, this design successfully withstands the necessary forces to realign the plunger's piston.
The tool is intentionally laid on its side for printing, so that layer adhesion wouldn't be a limiting factor to its function, and so that it could handle more force.
the built-in support is designed to be 1.2mm thick at its contact area, so that it would be printed with three 0.4 nozzle parameters, or two for 0.6 nozzles, and based on my experience it was easily breakable.
Adding additional supports for the tip of the arm is beneficial only for cosmetic reasons, do avoid tree supports though.
Successful print settings are as follows:
The author hasn't provided the model origin yet.