I would as Kvom ,said , grind the mag chuck true , when you do , do it with it turned on .
Cheers Rob
Now that's a tip I've not seen elsewhere, turn the chuck on when you grind it ... ta ..

That wheels very blue, don't let the missus see that

Kvom, How have you found the repeatability of removing the mag chuck and putting it back on again after you have ground it true? Is it doable? I only ask as I have a J&S grinding vice as well and I may wish to swap and change.

Fortunately there's a diamond hiding in this picture that came with the grinder ..

I was quite impressed how viciously it attacks a grinding wheel if you don't take it easy

