I had a meeting with Bossman this morning, highlighting my concerns. Somehow magically I was able to keep my emotions out of it (It's really hard to hide that someone is driving you around the twist) then we brought M in.
We discussed the review I'd written (thank you David H for the awesome wording suggestions) and all the issues I'd brought up. M, in a surprising act of professional Darwinism, ARGUED with me. Bossman pointed out that all the issues I was bringing up (with dates where I Could recall them) were serious and legitimate issues.
She's been officially demoted to just cleaning parts, which has its own set of details to be mindful of. Stuff needs to be cleaned a certain way, parts need to be "lapped" (smoothed out with emery cloth on some faces) and cleaned and dried a certain way, then put away in an organised fashion, in the correct places. She has a month to master that and if, after the month, I'm not satisfied, she will be let go.
I feel like a real jerk having to have done it, but there are safety and cost issues to bear in mind and those things are part of my job. As her supervisor, it's also my job to ensure she is doing her job correctly.
Good job on the write-up/meeting. That sounds GREAT. And she even argued about it, in front of you and Bossman? Hello, termination paperwork!
I do want to warn you about "cleaning parts". You state that "cleaned a certain way, parts need to be 'lapped' [smoothed out emery cloth] and month to master". Now - me personally am asking - is this procedure documented anywhere? Or is it a step-by-step you've created for the crew? Reason I ask this is that she may try the "it's not in the book" stunt. And "I need written instructions" (may slightly be true but if not brought forward by now it's worthless). Besides that, is this cleaning procedure VITAL to product quality? Will these parts be ready to use after cleaning (or meant to be reused?)
If these parts are to be re-used after the cleaning, I'd personally not trust her. By now she'd have been gone and only allowed to sweep the floors if anything. I suggest that you create an extra task for a crew member to 'double check' her work. (a person you trust at least). Create a checklist of all the possible parts to move through her area (hose, gasket, pipe, doohicky) and have person go oversee the quality of the cleaned parts. You will build documentation with this.
Actually - if boss DOES want her gone, try the above. And you'd have to have a person you trust ultimately (or your own self) to do this, as it's building ammo for her termination. You may have to create a whole new procedure for this, let it roll, see if it works at all and or catches her, then decide, "oh well, let's drop that kthxbye".
Plus, building this against her: she files for unemployment, she won't win. Terminate her w/o rehire eligibility, and no severance pay.
I wish you good luck, and your compassion..much more than I have.