THIS DEVICE IS SO SIMPLE & EFFECTIVE.
It allows the blade changer to avoid the really sharp jagged backs of blades (flutes that have worn away esp if used in sandy areas).Those backs of blades are way sharper than a new cutting edge side and can easily cut through riggers or welding gloves: that is why I made this. It is so dangerous, not just because of the minute tetnus causing organic animal manures etc in grass that attach to the blade but it is because we need to hold the back of the blade in order to loosen it. It can be paper thin to boot.
It also allows the user to block it against another part of the deck if two hands are requited on the spanner. This is very important on John Deere decks where the blade bolts can grow in excess of 1/2" absolute jamming it in the blade bolt housing. I used A section a gal pipe, large enough to fit over the 3/4" ratchet socket spanner handle to gain extra length and leverage. Kubota blade bolts dont grow in length but the heads wear away if stepped blades are not used. If stepped blades are used then extra pressure is applied to the blades (and bosses & washers etc) when cutting short & scalping or hitting rocks/stones occur.Heavily stepped blades can throw small missiles from under the deck causing a safety issue also. There is no fun in being hit in the face by a stone flung out and ricocheting from a front tyre or a nearby tree.
I must have been holding my mouth right when creating this as it is offset (A fluke for easier stick welding) allowing better holding of flat, stepped & heavily stepped blades. Simply flip it over to find the best spot.
Stay safe & wear PPE.