Miscellaneous

Seek & Geek teardowns

Eleven short weekly analyses from 2.77 Precision Machine Design at MIT, Spring 2018: find a real-world mechanism, take it apart, and run a first-order analysis on it. The weekly write-ups from the same class live with the T-Based Precision Lathe they built toward.

• SG-01 Seek & Geek 1: The Zippo Lighter

  Took a Zippo apart and worked through the oxidation physics behind the spark, a plate-yield estimate on the case, and the bi-stable cam that holds the lid.

• SG-02 Seek & Geek 2: The Indoor Rowing Machine

  Looked at the sliding seat's roller geometry and worked the fan flywheel's power dissipation, which goes as the cube of angular velocity.

• SG-03 Seek & Geek 3: The Ski Tow Rope

  First-order analysis of a bunny-slope tow rope -- resistance force, the hanging tensioner mass, tension propagation through the pulley network, and a capstan slip check.

• SG-04 Seek & Geek 4: The YuMi Collaborative Robot

  Used a labmate's ABB YuMi to work through homogeneous transformation matrices from first principles, then extended them to predict error at the end effector.

• SG-05 Seek & Geek 5: The Bicycle V-Brake

  Worked the V-brake's lever ratio from a moment balance, then used an energy balance to predict the stopping distance from 15 mph.

• SG-06 Seek & Geek 6: The Fencing Foil

  Analysed the buckling of a fencing foil with Rayleigh-Ritz, and looked at how the semi-circular cross section and eccentric loading force it to bend the safe way.

• SG-07 Seek & Geek 7: Merlin's Apprentice at Legoland

  Estimated the hydraulic piston force, cylinder pressure and total drive power for a spinning Legoland ride from photographs and ride timings.

• SG-08 Seek & Geek 8: The C-Clamp

  Derived the square-threaded screw's mechanical advantage, then found the handle yields at 102 N of hand force -- well before the clamp body does.

• SG-09 Seek & Geek 9: Planetary Gearboxes

  Derived three planetary gear ratios from first principles for a gearbox found in the lab, then traced the torque limit to the sun gear teeth.

• SG-10 Seek & Geek 10: The Traffic Light

  Built the free body diagram for a traffic signal mast arm, handled the taper by splitting it into three constant sections, and found 36 mm of tip deflection at a factor of safety of 13.4.

• SG-11 Seek & Geek 11: The Traffic Light, Continued

  Added the beam's own weight to last week's traffic light analysis, then sized the four-bolt mast connection for combined shear, moment-induced tension and clamping preload.