Installing or eradicating mortiser chisels is a careless job, and it will probably result in poked fingers or broken factors if the bit drops down and hits the mortiser’s metallic desk. My low-cost repair is to guard the sharp factors (and my fingers!) with the plastic cap that comes with most new mortiser bits. I set up the cap to assist push the auger and chisel up into place. Then I put it again on once I’m via mortising to stop the bit and chisel from falling as I’m eradicating it from the machine.