My 3D printer has two bolts used to help securely swap out nozzles. Basically each nozzle assembly has 2 holes that are perfectly aligned with another part on the nozzle.

The fit is SNUG like if the nozzle assembly isnt infinitesimally in the right place these will not go in.

I cant post a picture but if you look up "Bambu X1C Hotend Screws" you will see some images of the screw as well as some images showing where they go.

They used a M3x14mm bolt with some sort of flat head with a hex driver. Interestingly it is partially threaded. About 9mm of it is smooth and 5mm of it is threaded. And I cant look close enough but there is possibly somewhat of a ring inbetweeen.

Now the hole for a hex driver is already starting to strip and I am a month or two in. I noticed when I over tightened them with a driver and couldn't get them out with a ball end hex and had to get out a flat end hex. They sell replacement kits but I am very much interested in seeing if I cant buy a bunch of these so I can replace this somewhat frequently. I might also be able to find one made in a higher quality or with a deeper hex groove.

The issue is where am I supposed to find a M3x14 where only 5mm of it is threaded? I understand these are shoulder bolts but I cant really even find 14mm M3 bolts let alone ones which match exactly these.

I am guessing the lengths of shoulder on these is not standard?

So my question is mechanically why shouldnt/couldnt I just use a regular threaded M3 bolt?

Some thoughts:

1. This part goes through intense vibration and movement in a range of frequencies.
2. Maybe not the bolt specifically but this part is rated to go up to 300C

An "bonus" question is that the end of it has a bit of blue (what I am assuming is thread lock). When I looked up options here most cap out at 150-230C and while much higher temperature resistant ones do exist they seem suited for automotive and mention bolt sizes much larger than my M3. Realize this may not be strictly a mech e question.