I don’t know this will be a problem on the DIY printer I’ve just got working, but I suspect it will: I have a screw for fine adjustment of the bed level zero position. Would some type of thread locker adhesive help keep it in place, but still allow me to manually adjust it?
(Or maybe I need to add a Precision Piezo Orion to the carriage assembly and dump the screw and manual adjustment).
Try teflon tape on the screw, as many turns as makes it hold.
For my corexy I built a kinematic mount with the screws through a teflon block following Mark Rehorst’s advice. On my bed flinger I also made a kinematic mount, but just wrapped teflon tape around the screws. They’ve never budged. (I originally tried some loctite in the hole as well, which was not compatible with the teflon tape. I cleaned that out and used just teflon tape.) There’s a picture (upside down, during construction, sorry) here:
I’ve used nylock before for this purpose. Works okay if you have a larger diameter wheel for turning. Another option is always a jam nut too. But if they have a tendency to come loose I would look at heavier duty springs to keep the wheel wanting to stay in place. Seems like a lot of the printers out there use too light of springs in my opinion.
I tried a nylock and it seemed way too hard to adjust the screw, I thought I might rip the adjuster off the printer instead. The teflon tape seems to be working, but adding a spring might be a good idea if I have problems in the future. On the other hand, I just ordered a precision piezo Orion as a new gadget to play with, so perhaps I won’t even need the adjustment screw at all someday.
Both of my Printrbots and my Ultimaker-ish printer use nylock nuts to hold adjustment screws in place for the end stop switches. Yes, they are tight, but that is the point. They turn easily with a tool (hex wrench in my case) but then they stay put. I think they are great for this purpose, but I guess that opinion is subjective. YMMV.
I’m with everyone suggesting nylock nuts. That’s the entire purpose of them, is to make a screw that CAN be turned if you want, but won’t turn under vibration or general use. Another option is stiffer springs, so that the pretension force against the nut is greater. This is why everyone suggests “yellow springs” for Enders constantly. It’s because the additional force makes it much less likely that the bed will come loose over time and stiffens the mount.