What lets go and to cause Baler Needles to break?

Not being familiar with a New Holland baler, such as a 68 or 273, I am courious as to some of the differences between a JD baler and a NH in terms of timing and what lets go to cause the plunger to brake off the needles on these two brands of balers. Also, is a NH more prone to brake a needle vs a JD or vice-versa?

Just courious.

Thanks in advance,
Bill

Timing issues, needle brake, needle drive shear pin can all cause the needles to be in the bale chamber at the wrong time. Safety do if working will protect them. Needle adjustment (needles clear knotters by 1/32"-3/32") can cause needle damage due to impact with the knotter (so can losing the knotter hold down bolt). I suspect that a bent tucker finger or tucker finger drive rod could damage the needles however my experience is that the drive rod bends before the needles break.

The needles break when they are trying to tie a bale and the plunger moves into the chamber & cracks them off. Baler is "out of time". There is a plunger-stop which is a big heavy piece of iron on a pivot that is supposed to go into the bale chamber every time the needles do & will stop (violently, with the shear pin breaking) the plunger, saving the needles. However, it needs to be set up to the proper timing itself, and without grease often does not pivot as it should. In short, it might not be working or not be able to do it"s job at the right time all the time.

Also, if the needle brake is not holding the neeles up & out of the way, they could drift down into the bale chamber on their own a bit with vibration, and the plunger will clip them off. Again the plunger stop should have done it"s thing, but was frozen or not set properly.

--->Paul