I have the conversion kit too. Works good in heavy grass areas, but if you hit any
obstruction (rock, stump, etc) I can guarantee you will break some bolts. So far that is the only damage I have suffered. I did lose one blade the last time I mowed, but there again it was because I hit a hidden tree stump. The blades are the same ones they use on the 60'' finish mower, but cut it half and mounted with two bolts. I like it better for the grass areas, and easily change back to the two blades when I want to do some real damage.
You can get replacement blades at Mowerpart.com part # 90-125 for abour $7.00 each
plus shipping.