Machine shop at <a href="https://en.wikipedia.org/wiki/Charles_River_Museum_of_Industry_%26_Innovation" class="extiw" title="w:Charles River Museum of Industry &amp; Innovation">w:Charles River Museum of Industry &amp; Innovation</a>, with overhead belt drives. Watch making exhibit is on upper level.
<a href="//commons.wikimedia.org/wiki/User:ArnoldReinhold" title="User:ArnoldReinhold">ArnoldReinhold</a>
CC BY-SA 3.0
<span class="int-own-work" lang="en">Own work</span>