smash the disk out if you get enough out you will relieve the pressure and it'll loosen up.

I think after handling his tool roughly you should have told him to check his nuts before he used his tool in anger again.

If you let him know his nuts were stiff when you handled his tool then he may have to swallow it and get his nuts checked out, and you shouldn't have to handle his tool again.

It is possible he has slightly bent the spindle or threads so it cannot unscrew. If he fitted it and you didn't change anything and you did buy the replacement spanners I would say you were in the clear but talk to him to make sure he feels the same.

Back to the Thread title - why are you ignoring me on GrindR?

ARE YOU UNDOING IT THE CORRECt ROTATIONAL WAY,

Also hold tool securely and apply a blunt sharp bang to the removal tool, dont use any lubricant as it will soak into the inside of the tool and short it out

I'd buy him a new one and ask for the jammed one back, then you can try increasingly violent means to unjamb it, and you'll have one of your own for future. It should be possible, even if all else fails and you have to break the disc off and prise the bits out from under the nut to take the load off it.

Oddly, we had the same problem at the campsite on Friday. With the added bonus of the lock-button no longer locking the wheel when you pushed it in.

We ended up clamping the disk with a pair of molgrips, rotated the disk until the molgrips were jammed against the blade-guard and then "cracking" the tension on the locknut with a cold chisel and a hammer. Only took a tap or two to free it but it was never going to happen with the actual grinder spanner.

You can with help use a hammer and chisel to knock it out.

I only have issues when the heavy of hand tighten the lock nut

Better than hammer and chisel would be an impact wrench. Maybe do him a favour and phone a friendly local garage, see if they’ll do it for you.

Plusgas followed by a mighty ****ting?

Hmm, can't help but I've never used the spanner to tighten or undo a disc. Push button, tighten or loosen by holding and rotating the disc.

As above, find some way to lock the blade is position then it'll undo fine. But him a new lock nut from a parts site afterwards.

Hooray, he's managed to get it off. Cut the nut square and used a vice, splendid.
Nipped to Screwfix and gottim a new blade instead.

I’d buy him a new one and ask for the jammed one back, then you can try increasingly violent means to unjamb it, and you’ll have one of your own for future

That's the weird thing, I really really don't want an angle grinder in the house or garage. That's the main reason I borrowed rather than bought. The last thing I want lying around is something that'll eat my Pragmasis in sixty seconds.

Thanks all.

Should have said the edge of the blade; much more leverage there than at the axle via spindle lock or shaft flats.

Well you are a damn site better than my niece and her husband. Borrowed my electric tile cutter, and gave it back with a burnt out diamond blade. Obviously hadn't been changing the water enough despite me telling them to change the water every few cuts.

My son's mate borrowed a mouse sander and it died on him, so he bought me a new one.

PS I keep the angle grinder under the ottoman bed otherwise it would chop through all the locks in the garage.

Left-handed screw threads by any chance? In trying to undo it the wrong way you've nipped it up tighter than a nun's chuff so now he can't undo it the correct way?

Nut splitter?

Plusgas followed by a mighty ****ting?

Swipes right

Clamp.nut in vice -phnaaaar phnaaar

Push lock button turn the tool.

It'll come off. It can only be corrosion. The thread pitch on those is monsterous you didn't damage it.

Never do your dirty work with another man's tool!

I bought a cheap display angle-grinder, the lock button doesn’t work, so to change discs I clamp the disc in a vice and undo the nut that way. Seems to work ok.

You bend it you buy it.
Big hammer normally sorts out most things.

My son’s mate borrowed a mouse sander and it died on him, so he bought me a new one.

Sanding a mouse is never going to end well is it.....

You bend it you buy it.

Agreed in general @pk13 . The question here is whether I did 'bend it'. When I tried to undo the nut it didn't budge. When it went back to him it was the same.
Was it borked when he loaned it to me, or did something I did in the first hours/ minutes of normal use Bork it?

Breaking stiff or seized threads was a speciality of mine in a past career lol.

Penetrating oil and shock are your friends. As has been mentioned, using a hammer and chisel can apply a massive amount of instantaneous torque if there is some surface like a dog to get leverage on.

Failing that, these are handy to have (two if possible):

(Hint use sandpaper or emery cloth to get more grip)