I have a Black and Decker "Lawnhog" electric mower model MM875 which I am trying to change the blade on. I posted about my difficulty removing the blade on this forum several months back and with some perseverance and a lot of PB Blaster was able to get the retaining nut to finally break free and remove the blade. I have ordered a replacement but with a new and wet storm scheduled to arrive Wednesday night I would like to re-install the old blade and pick up as many leaves as I can before the rain arrives. I am reversing the order in which I removed the old blade which is the hard plastic blade dampener,the blade,the square metal spacer and finally the retaining nut. The shaft spins when I try to tighten the nut even when I hold the blade static.

Any advice is appreciated and the sooner the better.

Thanks to all