From the get go I turn with moving the carriage by hand. I have never used the the leadscrew to make cuts and I always get a rough finish. I am working on tool shape. I know about carriage stops, don't have one for my SB 9C lathe but what is the point? by hand you can hit a hard stop but turning with the leadscrew moving the carriage would be a disaster? Do the half nuts pop open when they hit a stop? I don't know and am not prepared to try it.