An adjustable measuring spoon I made that allows for measurements of substances anywhere from 1 - 30 ml or 1 - 6 tsp. Works with a piston that moves to reduce or increase the volume of the spoon with the turn of a dial. The dial has grooves to make it easy to use and turn and measurements in either unit are on each side. The spoon is assembled by placing the dial and piston head in the body and then screwing the piston through all three until it is tight. The dial can then be used to make adjustments to the volume after assembly.
Update: Modifications made according to suggestions in the comments. Perhaps also print it with a higher number of perimeters or more infill so that it isn't flimsy. I haven't printed it myself since my access to a 3D printer is limited so if there are any other issues, please let me know what needs to be changed so I can update it.
This model was created using Fusion 360.
The author remixed this model.
Modified handle to have a more ergonomic design, added grips to thumb-wheel to make it easier to turn, and added embossed markings for measurement units to know how to position piston for specific measurements.