Tools
How can I unscrew this bolt?
It is the bottom nut of an Optimus Polaris stove. I tried with the multi tool provided with the stove because I have no wrench (11 mm) which would fit it unfortunately, is too thin. But the multi-tool is failing since the nut is already a bit damaged and can't get a good grip. It is soaking in WD-40. I already tried heating...
Discussion
Spanner wrench or bit. Don’t have one? Take a cheap, large flathead and grind out a channel. DIY spanner driver.
It needs a slotted wrench of the proper size.
I'm searching but they look different, they are not rounded
All they need to do is fit in the slots.
Drill and easy out
I don't know - I mean there is the burner in the same bolt...
Face spanner wrench
I think is too thick
Spicy hammer.
Flathead
Fine nose pliers?
Tried but doesn't move
90 degree circlip pliers maybe?
Hammer and flat blade Screwdriver 👍
Along similar lines, but hammer and TINY cold chisel, like 1/4"..
That or VamPliers (or the Knipex or Japanese versions which I can NEVER remember the names of!)
Dremel a slot across the indents, large flat tip should get it.
Needle nose and a screw driver between the handles if I didnt have the appropriate tool.
Pig nose or snake eye security bit?
Amazon sells a set of 5 different sizes for $12, Amazon 🤷♂️
1 Locking Pliers Your highest chance of success will be with a pair of locking pliers, Vice-Grips Instead of trying to fit into the stripped notches, you'll clamp the pliers onto the round outside of the nut. Adjust the screw on the pliers so they lock onto the nut with a very firm grip. Once locked on, you should be able to use the pliers as a handle to turn the nut. 2 Add Friction to Your Multi-Tool: Try placing a piece of a wide rubber band over the nut before trying the multi-tool again. The rubber can sometimes fill the stripped-out gaps and provide just enough extra friction to get it moving. 3 Last Resort (Destructive Method) If nothing else works and you're prepared for a more drastic measure, you can modify the nut. Cut a Slot: Carefully use a Dremel with a cutting disc or a small metal file to cut a single, straight slot across the diameter of the nut. This turns it into a large flat-head screw. You can then use a large, sturdy flat-head screwdriver to get it out. Be very careful not to cut into the body of the stove itself. Given the situation, I would strongly recommend trying to get your hands on a pair of locking pliers before attempting the destructive method. It's the right tool for this specific kind of problem.
Will try but locking pliers I have no space enough for them...