locking folding knife V2.9 (Alpha)

Disclaimer:

(DO NOT USE THIS TO HARM PEOPLE, ANIMALS, PROPERTY, OR ANY WAY THAT WOULD VIOLATE THE LAW. THIS IS MEANT TO BE A TOY OR A PROP AND IT IS HIGHLY DISCOURAGED TO USE THIS FOR ANY PURPOSE OTHER THAN WHAT IT IS MEANT FOR)

parts needed

• size 33 rubber bands (probably has some wiggle room)

• one small but decently powerful pen spring.

How to assemble it

The first thing to do is to take your rubber band and find the hole at the bottom of the body and secure one end of the rubber band there, if you can't, you have likely found the wrong hole. After that, you're gonna want to attach the other end to the little notch on the blade part. Once you have that done you will want to take the largest pin and attach the blade to the body with it making sure the blade is pointing in. After you have the spring loaded part ready, you're going to take the second, smaller pin, and you're going to hold the blade in the closed position while you insert the pin into the final hole on the bottom. If it isn't sliding in, it isn't facing the right way. Make sure the square side of the small pin is facing towards the big pin. Then, take your spring ,depending on the size you might need to cut it in half, and put it in the spring cap and put the cap in the hole you just put the smaller pin in. After that, all you need to do is secure the spring cap to the knife body and it should be finished.  And remember, if anything is stuck, you can either scale it down and re-print it,or you can sand it.

How it works

pressing down the button should flip out the blade and lock it in place. Pressing down the button, pushing the blade in, and releasing the button should lock the blade in the un-deployed position.

Good luck and happy printing, also if you have any problems with the parts, just write the comments so I can fix it.

Version Updates

• 5/27/2026 V1.6 : I have added a new lock spring system, made some things better scaled, and made it much harder for rubber bands to get stuck in the joints.

• 5/31/2026 V1.7 : I have scaled the pins better.

• 5/31/2026 V1.9 : I addressed the locking pin spinning issue and made the locking holes on the plate deeper so that it locks better.

• 7/1/2026 V2.1 : I have re-addressed the spinning lock pin problem by adding an extension the pin so it physically cannot spin. I have also added a slanted area to the part of the blade the locking pin goes into so it locks easier. I will experiment with printing the blade sideways so the locking holes are printed better.

• 9/8/2026 V2.4 : shortened the locking pin to add more room for the spring. started working on a version model that has a manual lock insted of a spring loaded one. This will likely be a different model.

• 10/4/2026 V2.9 : Almost making final adjustments. Added better rubber band parts, so the rubber band doesn't get in the hinge. Hopefully fixed the "lock-pin not working because of friction from the rubber band" problem. scaled the whole model to the size I normally print it in (Finally!). Other spring-less designis still a work in progress.