I have walked up and down the level and I have not been able to locate the cog needed to activate the harvester. Where is it located? Is it even in this level?
It is located in this level. You need to go to the very end. The very last contraption you will make it to the exit and see the portal to leave the level. Go back to the machine and keep going against the moving platform. There is a second exit a little further up. The cog for the harvester is inside here. Getting back isnt as tough but is still a pain. Well worth it as you will get another health vial for this one.