https://www.teknic.com/model-info/CPM-MCVC-2321S-RLN/

3Nm is about 424 oz/inches. They want $284 plus shipping for the one in the link. Coincidentally, this is the same servo that is on my Z axis in the video link. That ballscrew actuator is a 5mm pitch screw. ClearPath makes essentially 3 different versions of each model: A high torque model, a high speed model and an intermediate model between those two. The "S" model linked in this post is their high torque version.