About this 3D model

My fiance tasked me with cleaning the bathtub, before tomorrow night. Well, I made the ultimate error; I accidentally scrubbed one spot a little too hard and revealed to her that the actual stock color of my bathtub is not, in fact, off-white as I'd claimed, but white. I did some quick mental math and realized I'd just finish scrubbing up the entire tub by tomorrow night if I didn't need time to sleep and my arms wouldn't fall off in the meantime. So I came up with a way to make it go MUCH faster! I started out making a design for this, but as I got into it, I realized I already had a part on my shelf that was basically the same design... the old gear from this print: http://www.thingiverse.com/thing:6544 Which didn't work in practice due to my inability to properly hob a bolt. But it would work here.!