Larger 6.35mm (¼in.) shafts are tougher, stronger, and ready for even the most stressful robotic applications. These thicker shafts are more resistant to both twisting and bending fatigue, meaning that you should have no fear of designing high-torque gearboxes or high-impact drivetrains.
The shaft is actually designed about 1mm shorter than its respective 8-32 Standoff. This means that, if you use standoffs to hold together two pieces of metal, the high strength shaft can rest on the high strength bearings attached to those two pieces without any cutting required – see Application Example picture.