Currently: 1 AA + 8 Buttons = 8 Cogwheels, 2 AA = 8 Shafts
It requires less Andesite Alloy per block to use Cogwheels in place of Shafts.

Suggestion: Make the Shaft recipe yield 16 Shafts for the 2 Andesite Alloy, and leave Cogwheel recipe as is. In this case, both would yield 8 blocks of coverage per Andesite Alloy.

You can use a Sawmill to create 6 Shafts out of 1 AA

It does seem unusual to require less overall andesite for the cogs than for shafts. However, cogs are used far more frequently in recipes and shafts have to improved recipe in the saw.
Thanks for the suggestion, but we'll keep it the way it is for now.