Lathe tool post and tool post holder sets include a tool post and multiple tool post holders, which are compatible with different styles of cutting tools. Toolholders maximize tool rigidity and minimize backlash to make repeatable high-precision cuts. Tool posts attach to the lathe's carriage to provide a base for securing and positioning tool post holders. Tool post holders mount on the lathe's tool post and hold cutting tools at a specific angle for machining workpieces. They have a quick-change system that speeds tool changes when making different types of cuts on the same machine.