Spacer kit question

[jcltyson]

PJ
I ordered the (blade) spacer kit to see if the quality of cut would improve on my super z xr7. The kit came in with three (3) spacers, there (3) bolts just under 4 inches long, and three (3) bolts approx. 2 inches long. Logic would say the longer bolts are required with the spacer/blade combination. What are the shorter bolts for?
Thank you.

[mowerconsultant]

We made a couple different shafts over the years.
The older version of the shaft did not have the threads recessed up into the shaft, the newer ones do, thus you need the longer bolt.