Wong,
Use the 1400 rpm speed -see what happens.
for turning - not for the 1500 abrasive.
The brown stain is a type of rust, but it is generally formed by the "smoke" you can see the "smoke" being drawn into the chuck.
What will get rid of it is "Navel Jelly" this is a rust remover, so any rust remover will remove it.
I wouldn't use any abrasives even 1500, until you have tried the rust remover.
Some metal polishes will work, perhaps use after the rust remover.
DaveH
Use the 1400 rpm speed -see what happens.
for turning - not for the 1500 abrasive.The brown stain is a type of rust, but it is generally formed by the "smoke" you can see the "smoke" being drawn into the chuck.
What will get rid of it is "Navel Jelly" this is a rust remover, so any rust remover will remove it.
I wouldn't use any abrasives even 1500, until you have tried the rust remover.
Some metal polishes will work, perhaps use after the rust remover.
DaveH