Lathe chuck jaws

[f350ca]

One of my three jaw chucks has two piece jaws, wish they both did. As Darren said the permanent part has keys that mate with the top jaw to line it up and carry the load when bolted down. You could use them as is for now, machining what ever shape you need to hold things, when they start to get used uo machine them off and make top jaws to fit. The only concern might be that the teeth that engage the scroll might not be hardened and will wear quickly.