I have just bought a new 301b Ingersoll Rand 90* die grinder. I want to use it for bringing the rusted areas of my Moggy back to bare metal and latter for cutting them out. I want to use a Scotchbrite type abrasive wheel disc for removing the rust and a cutting disc for chopping off the rusty bits, so do I need a shank/spindle so go with these or can I just buy the discs?