I have one that came on a used 4.5" metabo I bought & no matter how hard I try I cant get it tight enough by hand & the disc will spin under load. I have resorted to tightening it with a stilson wrench - wrong I know but it will do until I pick up a proper nut somewhere. Luckily I keep that grinder for grinding so the disc rarely needs changed.
On my 4.5" & 5" grinders I never use a pin spanner for tightening, just a gloved hand on the disc & I rarely need one for loosening. My 9" grinder rarely gets used but I always use the pin spanner on it just to nip it up.
On my 4.5" & 5" grinders I never use a pin spanner for tightening, just a gloved hand on the disc & I rarely need one for loosening. My 9" grinder rarely gets used but I always use the pin spanner on it just to nip it up.