A part inside might have jammed preventing a slip. The filament used may be different. The temperature it printed at may be different. The amount of oxygen to nitrogen in the air when it printed could make a difference. They may have lubricated it with graphite. There are so many reasons. One more thing, if you don't sandpaper off the burrs then there is more plastic in the way of the mechanism.
Also, reversing the tightened nut to see what torque it was torqued at is not a very accurate test. There is hysteresis in tightening, where the loose torque is probably different than tightening torque
Thank you for the feedback. I didn't print it and I don't have experience with 3D printing but I believe it was designed to break and that is why it had 3 inch pounds printed on the handle. Maybe I am wrong and it should slip and not break at 3 inch pounds but if that is the case it exceeded the torque it should slip at. I still am not sure what the design goal was with this 3D printed ratchet.
Honestly, the shearing force exerted on this design is going to be a problem no matter how you print it. I reckon the other designs on thingiverse that use a hex bit would be a better bet.
A part inside might have jammed preventing a slip. The filament used may be different. The temperature it printed at may be different. The amount of oxygen to nitrogen in the air when it printed could make a difference. They may have lubricated it with graphite. There are so many reasons. One more thing, if you don't sandpaper off the burrs then there is more plastic in the way of the mechanism.
Also, reversing the tightened nut to see what torque it was torqued at is not a very accurate test. There is hysteresis in tightening, where the loose torque is probably different than tightening torque
Keep testing.
you should have printed more perimeters that's why it broke
Thank you for the feedback. I didn't print it and I don't have experience with 3D printing but I believe it was designed to break and that is why it had 3 inch pounds printed on the handle. Maybe I am wrong and it should slip and not break at 3 inch pounds but if that is the case it exceeded the torque it should slip at. I still am not sure what the design goal was with this 3D printed ratchet.
Honestly, the shearing force exerted on this design is going to be a problem no matter how you print it. I reckon the other designs on thingiverse that use a hex bit would be a better bet.