It's welded and then ground smooth and retempered at the weld point. It's only steel. There's a raeson why steel is used so much in industry, it's a lovely metal to work with.
As for a spindle moulder, I've not had the pleasure. These, bandsaws and circ saws used to have a specific bit of legislation as "dangerous machines". They were permitted because they do a job, but they had complex guarding requirements, isolation from other operatives, nobody using them under 18, and so on. these days the laws are less prescriptive, they say "you will have an appropriate risk assessment and controls" so it's teh factory's problem. God help you if you injure someone and don't have proper controls, the HSE will do you proper. Quite right too.