I just received the NT-4000 set from Sinclair last week (through Brownells). The entire kit, with expander mandrel and turning mandrel, was only $90, so you won't "save hundreds" by eliminating one piece.I'm trying to control cost and buy the minimum I will need to start. So, if I already have Sinclair mandrels, that are the same size as the ones that come with the kit for turning necks, that will save me on that initial cost. I can pick up more as I go, but don't have several hundred to spend at this time. Though it might be a while since I noticed Sinclair is out of stock on their NT-4000's.