Pat mentioned that the carriage would need to be heavy to prevent chatter. Is chatter strictly a function of carriage weight or can it be reduced by slower speeds?
Well, yes and no. A well damped carriage will be less likely to chatter, faster or
slower can reduce chatter, etc. Chatter often occurs when the cutting tool grabs and the tool mount elastically deforms, when the tool releases, the system rings, causing the waviness known a chatter. If the speed is just right, the oscillations are reinforced by the movements of the tool.
A more rigid carriage and tool holder will reduce chatter, a loose carriage will cause chatter - there are LOTS of potential causes. A heavy carriage will compensate for imperfect ways or a flexible bed.