Crucible Chairpanzee Analog Computer

Chairmaking is complex enough without the trigonometry needed to calculate drilling and sighting angles for legs and spindles. The Chairpanzee is an analog calculator that does the maths for you: slide the inner card so the splay you want appears in the top window, choose the rake in the window below, and it shows the sighting angle. Flip it over to see the drilling angle (the resultant).

With the Chairpanzee you can:
Calculate sightline and resultant angles from photos of antique pieces, to copy a classic or borrow the angles
Use drawings or models to design new furniture and easily work out compound mortises
Understand the relationship between rake and splay more deeply and see how small changes cascade through a design

Facts:
For chairs, stools and tables with compound angles
Size 4" × 9-1/4"
Durable board stock with tough gloss coating, glued and eyeleted
Developed by Ed Sutton at FirstLightWorks in the UK
Printed and assembled in the USA