My grandmother had to work in factories under the Nazis toward the end of WWII, and anyone doing this sort of thing would have been taken outside and shot.
She says they were told not to work too slow, because that was sabotage, and not too fast, because that was bad for the morale of the others. Her main problems were with the POW workers (slaves), who tried to kill all the Germans they could. Several times, heavy weights were dropped off railings just above her, etc.
Same with my granddad, he had to work in the Opel factories. Their gig was to make cars that would function when tested, but that would fail within a couple of days of delivery to the field.
So, whenever they could they would structurally weaken some element deep in the engine just enough to make it fail.
This is a lot more difficult than it sounds, it is a study in planned obsolescence, because if you make it fail to soon you get a bullet to the back there is not a lot of room for error.
Finally they settled on making a fairly small cut in the wall of a piston, apparently that was good enough to survive a test or two but would fail quickly enough under actual use.
Second, how far you take the instructions in the booklet obviously depends on the work you do, and the higher up you are, the easier it is to screw up something without being found out.
She says they were told not to work too slow, because that was sabotage, and not too fast, because that was bad for the morale of the others. Her main problems were with the POW workers (slaves), who tried to kill all the Germans they could. Several times, heavy weights were dropped off railings just above her, etc.