Chris Sangwin

C. J. Sangwin’s linkage movies

Chris Sangwin has a nice collection of linkage movies at How round is your circle?.

Particularly nice are the straight line mechanisms such as Hart’s second straight-line mechanism.

His example of the Sarrus linkage is also found on YouTube:

Brock Institute Logo

Brock Engineering’s mechanism home page

Fred Klingener has generated a number of interesting mechanism animations.  My favorite is the Peaucellier straight line mechanism.  You will find a table of 16 or so animations at his site:

Brock Institute Logo

Brock Institute Logo

Bennett Linkage

Linkage animations on synthetica

This link connects to a web-page with a number of linkage animations. There are several planar four-bar linkages, several spherical four-bar linkages, and an example of a spatial four-bar linkage called a Bennett linkage that is shown below. This page also includes a number of spherical linkage animations generated by students some years ago. (UCI Robotics and Automation Lab)

This animation was generated by HaiJun Su using POV-Ray. It is a Bennett linkage designed to guide the coupler linkage through three specified task positions:


Kinematic models for design

The KMODDL team at Cornell University maintains an excellent digital library of kinematic models with animations.  Access their site at the link:




Machine screw dimensions

According to Shigley and Mischke’s Mechanical Engineering Design (McGraw-Hill 1989) experiments show that the tensile stress supported by a threaded rod equals that of a rod with diameter that is the mean of pitch and minor diameters of the threads.  Thus, the tensile stress area of a threaded fastener is computed from the average of its pitch and minor diameters.

  • Little machine shop provides downloadable lists for tap and clearance holes:  tapdrillsizes.pdf
  • And large listing of fasteners can be found at SmithFast.


Spherical Car Door

Spherical eight-bar linkage for a car door

This spherical eight-bar linkage was designed by GimSong Soh to guide a car door from the side to the top of the vehicle. This animation shows the versatility of movement provided by these linkages. (UCI Robotics and Automation Lab)

Diesel Engine Animation

Diesel Engine Animations

This are two animation of the operation of a diesel engine.  The first focuses on the four stroke cycle. The second start with the turbo-charger, and makes its way through the engine.

Engine Animation

Engine Animation

This YouTube animation shows the animated assembly of a solid model of a four-cylinder engine.  It interesting just to see the number of fasteners, but it is worth waiting for the animation of the four-stroke cycle that occurs about two-thirds through.

Welcome to Mechanical Design 101

Mechanical Design 101 is a collection of resources to educate, guide and perhaps inspire the mechanical designer.  Please send me links to your favorite resources, and to interesting and useful examples of mechanical devices. I would also appreciate a note, if you see any errors. Thank you, Michael McCarthy