seized grinder nut

Which way does the thread run? What do the instructions say about that?

You've locked the spindle, I take it?

I can't see why dismantling it would help. These things are designed to be undone without dismantling. Why not return it?

My immediate thought also. LH or RH thread?

They'll refund but don't want it back, so I don't mind wasting a bit of time on it

Usual grinder direction, clockwise afaik

Stuart, do you think you could consider either switching this pointless message off, or correcting the separator (it should be "--

Have you looked at the thread? Have you locked the shaft? Are you using the appropriate tool?

Tim

yes yes and yes

In that case I think you need to post some pictures because I'm darned if I can work out why it won't undo.

Tim

Look, either read the instructions, or just try unbolting it in what you regard as the wrong direction. It won't do it any harm.

It's a bog standard grinder design but, as usual it's difficult to engage the lock and get any sort of pressure on the nut. It's obviously been over tightened at the factory

I reckon you've got more of an idea than the suggestions so far. I don't see how else you'll lock the spindle.

NT

Have you tried fixing the machine to a heavy bench with a vice, clamp or whatever, getting a short well-fitting spanner pre-tensioned against the locking pin with a wooden lever (a metal one has too much elasticity) and tapping it quite hard with a big hammer when everything is stable and the forces are all in the right direction? The only thing after this (and before cutting the nut) is to try a cold chisel directly on the corner of the nut in the correct rotational direction an impulse tool or a socket with a very long lever. But the last one will probably break the locking pin or the casing of the grinder.

There's a specialist web site called Grindr, and I'm sure someone there will be able to help with your nuts and shaft.

Cheers

Perhaps it was misthreaded from new (or the thread has galled in some way) - so it may never undo...

Take it back and ask them to get it off if its new. Brian

Have you tried an impact driver on it?

Sounds like something you need an angle grinder to resolve !! or a nut splitter. Anything more severe needs the shaft removing so you don't damage the gears.