ion of the instrument has
been made to the earlier Emanuel, chiefly on the basis of his recognized
position as an outstanding craftsman.

[Illustration: 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.]

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 craftsmen 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 surprising 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.

[Illustration: 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 6 shows the traversing spindle and nut removed from the machine.
Provision has been made for doing this so easily that there is every
reason to believe that, originally, there were various different spindle
and nut units which could be interchangeably used in the machine.
Additional evidence tending to support this concept exists in the
cutting tool (fig. 4), which must have been intended for serious work as
it has been carefully fitted in its unsymmetrical socket. The cutting
blade of this tool, which works with a scraping rather than a true
cutting action, is too wide to form a properly proportioned thread when
used with the existing lead screw. This