
When breaking is the point
The shear pin that connects a post hole auger to a tractor PTO is designed to break when the auger bit hits an obstacle, like a rock or piece of metal. This way, instead of grinding through something important, or damaging the gearbox, the PTO shaft, or the tractor itself, the (relatively) inexpensive shear pin breaks. The digger stops, and the operator can assess the situation, clear away the obstacle and replace the pin, before resuming digging. However, one hot day, I got impatient after shearing three pins while digging post holes through heavy, rocky soil. Grumpy, sweaty and irritable, I made the mistake of replacing that third shear pin with a grade 8 tempered steel bolt of the same diameter. With this unbreakable bit of hardware, I finished digging the post holes quickly and easily, in a fraction of the time.