Electrical resistance strain gauges have a metalic foil in a pattern encapsulated in a substrate material. They are bonded to bonded to components under test or used in various types of transducers. As the material they are bonded to strains under load the resistance of the foil increases. This change in resistance can be measured […]
A boring machine, which I’ve also heard called a barn drill or a beam drill, was used for creating mortises and other activities in timber frame construction. The replaced the older t-handle augers. They were operated by placing them on the beam and sitting on top of the wooden base. A lever released the bit […]
A vernier caliper is a measurement very simple device for making extremely precise measurements (up to 0.001 inches). Here’s an article on how to read one.
Slide rules were used to perform mathematical calculations prior to the invention and wide-spread availability of calculators. This page describes the many different things you can do with a slide rule, or you can watch any number of YouTube videos on the topic. Just like calculators today, there were a plethora of different manufacturers and […]
The library of congress maintains the Historic American Buildings Survey (HABS), the Historic American Engineering Record (HAER), and the Historic American Landscapes Survey (HALS). If you’ve ever wanted to know more about a historic site, search the collection to see what you can find on the Library of Congress website.