Self-explanatory:
Download as PDF, print and glue on cardboard:
[Thickness ruler version 1] Prints 70mm as 71mm with Win7 / Adobe Reader 9.3.4
[Thickness ruler version 2] Prints 70mm as 70mm with Win7 / Adobe Reader 9.3.4
Try which version works better with your computer and printer.
Times are from Douglas Baldwin's Practical Guide
--PedroG 20:54, September 7, 2010 (UTC)