Re: 4 1/2 " grinder
They're used a lot for cutting ceramic tile. So you'll be able to find them at any home centre. But the best prices on them are usually at discount tool stores. Up here I get mine at Princess Auto, I guess something like Harbour Freight would be where you would get it? Before you go shopping, make sure you know the arbor size of your grinder (5/8 or 7/8 usually).<br /><br />There are two kinds of these discs (they all look like a smooth metal wheel), one with little slots cut in it, and others that are solid. You want the one with slots which is used for dry cutting. They're really quite amazing - try hitting a brick or a bit of stone with them.<br /><br />I've only used common metal grinding wheels for grinding - the ones that are about 1/4" thick and say they're for ferrous metals. But I think a heavy grit flap disc might work really well too - maybe much better than a solid wheel. These are like a grinding wheel with a hundred little sheets of sandpaper glued to them.
