Stanley vulcanite railway curves
I recently came by a set of W.F. Stanley railway curves made of vulcanite (also known as ebonite or hard rubber), included almost as an afterthought to an ebay listing…
Sketchy calculation
As a bit of weekend fun, here's something called a Rechenstift - German for "calculating pen" - by the venerable Hamburg firm of Dennert & Pape, erstwhile inventors of the…
Fan scales
A recent discussion with Peter Hopp of Slide Rules fame, prompted by an item in the latest UKSRC Newsletter, finally encouraged me to photograph some of my fan scales. This type of…