M4 lock nut has ... locked!


Has anyone had problems with these lock nuts? We were assembling the six legged robot and fitted a lock nut as indicated, but it has locked permanently. I guess there must have been an issue with the thread, but we’re now unable to dissasemble a wheel and other components - have tried WD40 etc. but looks like we may need to resort to a hack saw. Any advice from Tech Support would also be welcome!


Hi Rob1,

Do you mean that you don’t know how to unlock this nut?
If yes, we will send an video to your email address to guide unlock it. Please kindly check if you can receive the email from pCloud transfer.


Thanks for sending the video. Yes, this is the lock nut we are using but the problem is NOT that we don’t know how to unlock it in the usual way, using a spanner. It is that for some reason the thread on the nut or screw seems to have failed so that it is permanently jammed and the spanner will not work.

Assuming that is the case, I guess we’ll have to saw through the screw in order to release the other components, including the wheel.

Have you had any problems with defective screw threads or nuts? - maybe we were just unlucky.

Best regards



Just to add, I have now sawn through the screw head with a junior hacksaw to release the other components. So now only problem is that we need one replacement M4 lock nut and one M4 x 30mm screw. Do you supply spare packs?


Hi Rob1,

Normally, there are 16 M4 Lock nuts and 4 M4 X 30 Screws in the six legged robot package.
I am not sure which form you are going to assemble, it looks like each form doesn’t need all of the 16 lock nuts and 4 M4 X 30 screws. Please check your package and see if you can find more.

Since the screws are consumable parts, so we always add several more in the package. If you need more, you can look for it from the local shop or buy the spare parts from our official website.
M4 Lock nut.
M4 X 30 screw