In a previous project https://forum.freecadweb.org/viewtopic.php?f=24&t=28433 I investigated the use of Body shapebinders to link the rotating and reciprocating parts in a simple twin cylinder. Although this worked quite well, it should be noted that each of the shapebinders were linked to each other by external geometry links. This makes the model unstable if any of the body features are modified which change the number of vertices, edges, or faces.
In this project, which is a much more complex articulating mechanism, I wanted to explore any advantages of using a single mastersketch to link all of the moving parts in a more robust manner. The model was created from drawings of a design by Gerry Dykstra available at http://www.john-tom.com/html/SteamPlans2.html
I used the fastener workbench for all of the stationary screws, nuts, and washers but had to create all of the fasteners for the moving parts from scratch. AFAIK there is no way to attach a workbench fastener directly to a vertex in the mastersketch shapebinder although they can be attached to edges of the moving bodies.
IMHO the single mastersketch approach is much more robust than chaining body shapebinders. Any of the body features can be changed without affecting any other body. The approach does take more planning of how the model will be created in the beginning of the process since every body depends upon the mastersketch. Attaching sketches to shapebinders of a mastersketch requires a bit of different thinking than attaching to faces, but I have found from this exercise that it is quite possible to create a robust and complex model without using faces or edges of bodies.
FreeCAD V0.17 capabilities never cease to amaze me, especially this new generation of PartDesign.
Now, for something more challenging....
OS: Windows 10
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.17.13519 (Git).
Build type: Release
Python version: 2.7.14
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 7.2.0
Locale: English/UnitedStates (en_US)