# J3 Gearbox Mounting Guidance for the J2-J3 Joints of a 6DOF Robotic Arm

- Source: Reddit r/robotics
- Published: 2026-10-21T19:47:48.000Z
- RoboHot: https://robohot.news/en/items/xursf2di2n7qv1m2iyrvk61gy
- Original: https://www.reddit.com/r/robotics/comments/1xbxe1t/j3_gearbox_mounting_guidance/

## Summary

A Reddit user is seeking a reliable mounting solution for a NEMA 23 gearbox on the J2-J3 linkage of a 6DOF robotic arm, hoping to mount the motor and gearbox directly on the joint as the AR4 robotic arm does, rather than using belt drive. Harmonic gearboxes and flange-output planetary gearboxes were ruled out because they exceed the budget for a university graduation project.