Step 5: Glue on the Top Layer
It is important not to get glue in the gears because if you do, it could interfere with the gear movement or glue them in place. Alternately, if the glue isn't close enough to the edges the mechanism will slip.
For this step it is best to leave the rack out, it can be easily inserted later.
Once the glue is evenly applied, press on the top layer. Be careful that the gear doesn't slip out of place and get stuck in the glue. If a little glue did get stick on the gear, you should be able to loosen it with the knife.