Threads

[Subdeacon Joe]

http://www.basiccarpentrytechniques.com/Manufacturing/Screw-Thread Cutting Since 1480/Screw-Thread Cutting Since 1480.html

 

Figure 3.—Small thread-cutting lathe which was made to be held in a vise during use. It was found as shown here, with only the operating crank missing. The overall length is approximately 12 inches, depending on the adjustment of parts. (Smithsonian photo 46525B.)

 

 

Figure 7.—Thread of modern form recently cut, using the old screw and nut but with a new tool. The material threaded is carbon-steel drill rod. (Smithsonian photo 49276A.)

 

 

 

 

 

 

 

Figure 2.—Cross-slide for the thread-cutting lathe of Das mittelalterliche Hausbuch, shown in figure 1. It is remarkable not only for its early date, but also for its high state of development with a crossfeed screw which had not become universally accepted 300 years later. The cutter, shown out of its socket, is obviously sharpened for use on wood.