Robbo3":1hjhs5sm said:I'll just add the same as the above.
As you have a 5" (125mm) grinder, you will find it hard to find a wheel other than the standard grey aluminium oxide. Also a 5" wheel puts a more concave (hollow) grind on the tools which can make them harder to use successfully. Note, I didn't say unusable, just harder to use.
A 6" or even an 8" grinder with white, pink (red) or even blue wheels is generally considered the norm for woodturning tools.
Lots of good information on the Peter Child woodturning site,
Jumps - are you sure that the grinder shafts are 20mm? Most grinders are 1/2" (13mm).
Jumps - Apologies. Forgot that bit.
Brian - Repeated my original post as it's the same as most of the others are saying.
Seems like you are in the market for a new grinder.