The pegs on the travelling steady lead the cutting tool when screwcutting.

Safety: Grip the workpiece in a chuck, not between centres.

When srewcutting between centres there is always the risk of the lathe carrier slipping under load. Should this happen, the work will cease to rotate, but the tool will continue its travel along the bed of the lathe until the clasp nut is disengaged, during this period, the work will lift itself over the top of the screwcutting tool, tearing the centre holes, finally, come out of the lathe altogether.