Tach main 2

Today we’re building a fully operational, sturdy plywood 3D study model of German engineer Dietrich Uhlhorn’s 1817 invention, the Tachometer, used throughout the 19th century in locomotives and later–and still today–in automobiles.  It’s a mechanism that, when the handle is rotated, movement is transmitted through a reducer, increasing the revolutions per minute (RPMs) and displacing twin weights in a rubber band-powered centrifugal unit.  The higher the RPM, the more centrifugal force separates counter weights, shifting a movable axle with a flywheel.  A dial is fixed to the axle, and the more the axle shifts (the higher the RPM), the more the dial arrow deflects, indicating higher speed rotation.  It’s the UGEARS Tachometer, the fourth model we’re testing after the 2-in-1 Arithmetic Kit (reviewed here), the Gearbox (reviewed here), and the Random Generator (reviewed here).  The Tachometer is part of the model maker’s STEM Lab series, educational tools and fun models that aren’t just for kids.  This kit, like the Gearbox we reviewed, is part of understanding basic engineering assembly design, most apparent in your family automobile.

Continue reading