There was a time when print-in-place moving parts were a curiosity, but [Tomek] shows that things are now at a point where a hand-cranked turbine blower with integrated planetary gears can be entirely 3D printed. Some assembly is needed, but there is no added hardware beyond the printed parts. The blower is capable of decent airflow and can probably be optimized even further. Have a look at it work in the video below.Every piece being 3D printed brings a few advantages. Prefer the hand crank on the other side? Simply mirror everything. Want a bigger version? Just scale everything up. Because all of the fasteners are printed as well as the parts, there’s no worry about external hardware no longer fitting oversized holes after scaling things up (scaling down might run into issues with tolerances, but if you manage an extra-small version, we’d love to hear about it).There are a few good tips that are worth keeping in mind when it comes to print-in-place assemblies with moving parts. First, changing the seam location for each layer to ‘Random’ helps make moving parts smoother. This helps prevent the formation of a seam line, which can act as a little speed bump that gets in the way of smooth movement.The other thing that helps is lubrication. A plastic-safe lubricant like PTFE-based Super Lube is a handy thing to have around the workshop and does wonders for smoothing out the action of 3D-printed moving parts. And we can attest that rubbing candle wax on mating surfaces works pretty well in a pinch.One downside is that the blower is noisy in operation. 3D printed gears (and even printed bearings) can be effective, but do contribute to a distinct lack of silence compared to their purpose-built versions.Still, a device like this is a sign of how far 3D printing has come, and how it enables projects that would otherwise remain an idea in a notebook. We do love 3D-printed gears.