My only concern with the shear pins would be them Shearing... Normal bolts would probably work. I dont see any problem using a hex bolt with an UNTHREADED shaft for the portion that would be in the axle.
Mike
I agree with BBgarage, i don't see a problem whatsoever wih using regular bolts. Keep in mind there are two holes on the axle, putting the bolt in the inner hole will lock the wheel to the axle, putting the bolt to the outer hole will let the wheel freewheel.
Do not put both bolts to the outer hole, if you do the blower will not move. With the bolts in both inner holes both wheels will be engaged for best traction, however more difficult to manuever. I generally keep mine with one in the inner hole and one in the outer hole for easy manueverability, but sometimes if the end of driveway is too high I must engage both wheels. Use the blower for this storm with the bolts, then either have HomeDepot or Ariens replace the missing ones with original parts.
I think you'll be hard pressed to find an available Ariens machines in Home Depot in Suffolk/ I know Commack has none, Deer Parks has none either. I was in the Bayshore store yesterday (Friday) and picked up the last Ariens 7624 for a friend, they had three 926's left in boxes but the assembly crew was there to assemble and I'm quite certain those flew out the door very quickly. Just to give you an idea, I saw eight 7524 in boxes on Thursday, by Friday at 11 am there was one left. The weather report created the panic buying not to mention the 50 % off. I found the Bayshore store had the most inventory remaining at the time when the others sold out. That may be your best chance to get some, I highly doubt there are any left or that they even would give them to you since it would prevent them from selling the machine. Use the bolts for now and get the job done is by best advice.