The tensioning screw on my Creality sprite pro shaved off, including the square nut inside. The screw is very odd, never seen it before, anyone know what the screw is?
Note, the original screw and nut are left handed, but if I get a right handed nut and (hopefully) screw, it shouldn’t be an issue.
I would call that a shoulder bolt. You are correct though it’s very odd.
I cannot think of anything I would have here you could use to replace that. I would think a right hand should work but the shoulder on that bolt is going to be the kicker.
Where can I find reverse square nuts? That’s probably the issue here, the screw still looks usable.
Ended up not needing a extra screw or nut, got it through using pliers, and it’s able to rotate in the screw. However it didn’t solve the initial problem I had. When I got the printer, around end of November 2022, I got a free spool of Spectrum SFLEX. So I decided to print a phone case a couple of days ago, however halfway through, it just… stopped extruding. I tried extruding PLA (with the same tension) and that works fine. I cancelled the print and tried manually extruding using the sonic pad interface, the gears spin good, but the filament doesn’t move at all.
I’m guessing the filament notches got clogged and couldn’t get a grip on the SFLEX. You could have also had a nozzle blockage, which would make everything worse. Since you have everything apart or at least comfortable with taking it apart, take a look at the gears and the filament notches and clean out if necessary.
I don’t know the Sprite, but you might want to do a “cold pull” on it to make sure the nozzle is clear:
Personally, I find cold pulls to be better at resolving blocked nozzles than the thin pieces of wire that usually push the blocking material further back and have problems a few minutes after you’ve “cleared” it.
I don’t think the issue is due to a clogged nozzle since PLA extrudes fine, I even did a cold pull before I disassembled the Sprite and it did no change.
Also, I’m assuming the filament notches are the little lines that are on the end of the filament from the gears when I take it out? If that’s the case, I noticed that there are absolutely no notches on the SFLEX when I take it out, I also noticed when I have to take it out, unlike PLA, I need to pull harder as if its “stuck” when it’s not. When I disassembled the Sprite, there was no stuck filament inside whatsoever.
We’re not talking PLA, we’re talking flex which will use any excuse not to extrude properly. I was told to do the pull test by Micro Swiss technical support and I was surprised at what came out of the nozzle at the end of the filament.
You should see notches on your flex (just like PLA) - you may need to increase your tension for it.
I have gotten some amazing models printed with flex but it’s a real pain in the ass to work with.
Alright after opening the extruder (again) and redoing it, I made sure this time the gears grab the SFLEX, and this time it extrudes! I am never touching the tension screw ever again 
