I disagree manufacturers installed a slip clutch for several very good reasons. If needle brake isn't snug enough to hold needles in home position when knotter trips needle frame will lower allowing ""plungerhead stop if operable"" to block travel of needle frame & needles shearing flywheel bolt.
If slip clutch is inoperable somethings going to break!!!!! Slip clutch not only protects baler but it also protects the tractor pto driveline.
My observation from being employed at JD dealership for 21 yrs many yrs ago is most slip clutches over overlooked/ignored IE not serviced. Slip clutch should be loosened & slipped then retightened at the beginning of each season.