.'. 



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 de- 

 velopment 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. 



This proved to be an instrument of the traverse-spindle 

 variety for threading metal. Fortunately, all essen- 

 tial details were present including a cutter (a in figure 

 4) ; this instrument was identified by the signature 

 "Manuel Wetschgi, Augspurg." The Wetschgis were 

 a well-known family of gunsmiths and mechanics in 

 Augsburg through several generations. Two bore 



the given name Emanuel : the earlier was born in 1678 

 and died in 1 728. He was quite celebrated in his field 

 of rifle making and became chief of artillery to the 

 Landgrave of Hesse-Kassel shortly before his death 

 in his 51st year. Little is known of the later Emanuel 

 Wetschgi except that he was at Augsburg in 1740. 

 Tentative attribution of the instrument has been made 

 to the earlier Emanuel, chiefly on the basis of his 

 recognized position as an outstanding craftsman. 



In several respects this little machine differs from 

 its predecessor of the Hausbuch, as might be expected 

 when allowance is made for the generations of crafts- 

 men who undoubtedly worked with such tools over 

 the roughly 200 years of time separating them. 

 Another factor to consider when comparing these 

 two machines is that one was used on metal, the other 

 probably only on wood. Therefore, it is not surpris- 

 ing to find on the later machine an outboard or 

 "tailstock" support for the work. The spindle of this 

 support has to travel in unison with the work-driving 

 spindle so that it is not an unexpected discovery to 

 find that it is spring-loaded. Figure 5 shows how this 

 spring may be adjusted to accommodate various 

 lengths of work by moving the attachment screw to 

 various holes in both the spring and in the frame. 

 Also visible in the same illustration is a rectangular 

 projection at the other end of the spring which 

 engages a mating hole in the "tailstock" spindle 

 to prevent its rotation. 



Figure 6 shows the traversing spindle and nut 

 removed from the machine. Provision has been 



Figure ;(. Smali thrj ad-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.) 



108 



BULLETIN 240: CONTRIBUTIONS IROM THE MUSEUM OF HISTORY AND TECHNOLOGY 



