I was getting weary of finding a piece of scrap to jam into the blade every time I needed to change a blade on my table saw. The nifty bright yellow blade locks looked interesting, but I just never wanted to lay out the cash for one. The arbor allows for a wrench to hold the shaft still while you back off or tighten the nut, but a normal 7/8" open end is too fat for the clearance allowed.
So, last time I was in sears I stopped into the tool section to find a skinny wrench. (Careful Chuck) I never knew this before, but they are called tappet wrenches, and sure enough, they had a whole set of them - 4 in all. Unfortunately, they wanted $28 for the set. Too much for me. OK, how much fr just the 7/8"? $24.00 !?!?!
On to eBay. Picked this 'oldie but goodie' up for under $9 including shipping. Works great, and better than a piece of scrap.