I found some identical sized and grooved, although silver grade 5, at my local hardware store. They are listed as replacements for "Ariens" model snowblowers. Ran it for a few hours today with one in the impeller and one in the auger with no issues. Worst case scenario I see is it will go through them faster than the OEM grade 8's. But at $2 each vs $20 each for OEM I figure I can go through 10 of the grade 5's from the hardware store and break even 