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Figure i. Earliest representation found oi v master-screw rvpi of thread-cutting machine. I i the incon- 

 sistencies, such as ' ight- and left-hand threads on mastei and work, it appears thai the ai ii-i bad s< anl insight into 

 actual function. From plate 62 of Das mittelallerlichi Hausbuch, nach dem Originate in on Waldburg- 



11 1 1 /> \'ercin\Jiir Km Helmuth Th. Bossert und Willy F. 



Muiil. (Leipzig: 1.. A. Seem.mn. 1912). 



through to the present time. The artist, whose 

 drawings give us our onl) knowledge of the 

 machine, himseli was obviously not very familiar 

 with the details of its 1 1 nut ion. Reference to figure 1 

 shows thai the threads on the lead screw and on the 

 work, wind in opposite directions. This must be an 

 error in delineation since the two are closel) coupled 

 tog ther without an) intervening mechanism so that 

 the only possible result on the work musl be a due. id 

 winding in the same direction as on the original 

 screw. The work also is shown threaded for its 

 entire length; this cannot he accomplished with an) 

 one location of the cross-slide. We arc left with 



the question of whether this slide was used in two 



locations or whether the artist, possibl) working 

 notes or an earlier rough skew h, tailed to show an 

 unthreaded portion on one end or the other of the 

 work. 



Of .11 least equal importance with the lead screw 

 and work and their relationship to each Other is the 

 tool-support with its screw-adjusted cross-slide ft 

 Just how this was attached to the frame oi the machine 

 so that it placed the tool at a suitable radius is again 

 a questionable point. The \er\ well-developed 

 Cutting tool is sharpened to a thin, keen edge tOtall) 

 unsuited for cutting metal hut ideal for use on a 



softer, fibrous substance: undoubtedly wood, in this 

 instance. Unfortunately, the angle at which the 

 artist (hose to show us this cuttei is not a view from 

 which it is possible to judge whether or not the tool 

 has Keen made to conform to the helix angle ol the 

 thread to he cut. This cross-slide, in conjunction with 

 the traversing work spindle, gives us a machine 

 having two coordinate slides yielding the same effect 

 as the slide rest usually attributed to Henry Maudsla) 

 at the end of the 18th century. Actually, an illus- 

 tration of coordinate slides independent of the spindle 

 had been published .is earl) as 1569 b) Besson ' and 

 know ledge of them w ideh disseminated l>\ his popular 

 work on mechanics. These slides are shown as part 

 of a screw-cutting machine with a questionably ade- 

 quate connection. Ii\ means of cords, between the 

 mastei si 1 ew and the work. 



li was tin- author's pleasure recently to obtain for 

 the Smithsonian Institution and identify a small. 

 nicely made, brass instrument which had been in two 

 collections in this country and one collection in Ger- 

 many as an unidentified locksmith's tool (fi| 



1 Jacques Id : umenls mathimatiques, el mUhaniques, 



Servants a V intelligence de fillisters chases difficiles, iff necessaires A 



loules rfpubliques, 1st ed ans, I >69 \lso 



n.. ns in French, German, and Spanish.] 



PAPER 37: SCRIW-Illkl \I> t:l lll\(, \',\ 111! M ASI KR-Sl :RI AV Ml HUH) 



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