Securely lockable carabiner

Use case

This design was originally done to fix my company ID cart to my trousers at work. I needed to be sure that I do not loose this card, so I decided to come up with an own design that is securely lockable. Feel free to use it for whatever you need to fix to some other part. The only limitation may be the opening slot that is only 6mm wide, and the maximal strength of your material of course. 

Printing

Printing these parts is actually very simple. Both PLA and PETG are successfully tested, but assembly is much easier with PETG, thanks to its flexibility. Just print both parts in the uploaded orientation. I recommend 4 perimeters and at least 25% of infill. No brim or supports are needed.

Assembly

Yes, a bit of force is needed to bend the carabiner sideways to screw on the nut. But that is only needed once. A vise helps to hold one side while you bend the other side. With PETG it works fine, but even with the more bridle PLA it was tested successfully without any permanent damage to the part. 

It may be a good idea to use the straight threaded rod to test and wear in your nut before you do the more complicated assembly step of putting it on the carabiner.

My printed thread is too tight, what now?

If your printer is calibrated well, the tread will fit well, at least on the full size version. I have tested it on three different printers (Prusa i3 MK3S, Prusa Mini, Ender 2 Pro). If it does not fit, likely your extrusion factor is too high. I recommend to adjust it as explained by Pursa. https://help.prusa3d.com/article/extrusion-multiplier-calibration_2257

If you don't dare to mess with this parameter, simply use the versions with more mechanical play that I have added to this post. Or you can simply scale your nut in X and Y direction (not in Z direction) to make it big enough.

Scaling

This part can be successfully scaled down to ¾ and to ⅔ of it's original size. The smaller you get, the more tricky it will be to fit the nut on. With a Prusa i3 MK3S this worked fine, but on the Prusa Mini things got really tight. You may need to scale your nut up in X and Y direction (not in Z direction, that would mess up the pitch of the thread) to make it work.

Please like it if you like it

Your satisfaction is my reward. Please give me a like if you like this part, or even better, share a picture of your print. I'd love to learn which application you use this part for.

Disclaimer

Even though I find this design very tough and secure, it is purely your choice what you do with this part. I will not be responsible if you face any damage to property or injury or death of people or animals. Don't be so crazy to use this part for climbing etc.