<P> During the first half of the nineteenth century, the US government included in their treaties with many Native American tribes, that the US would employ blacksmiths and strikers at Army forts, with the expressed purpose of providing Native Americans with iron tools and repair services . </P> <P> During the early to mid-nineteenth century, both European armies as well as both the U.S. Federal and Confederate armies employed blacksmiths to shoe horses and repair equipment such as wagons, horse tack, and artillery equipment . These smiths primarily worked at a traveling forge that when combined with a limber, comprised wagons specifically designed and constructed as blacksmith shops on wheels to carry the essential equipment necessary for their work . </P> <P> Lathes, patterned largely on their woodturning counterparts, had been used by some blacksmiths since the middle - ages . During the 1790s Henry Maudslay created the first screw - cutting lathe, a watershed event that signaled the start of blacksmiths being replaced by machinists in factories for the hardware needs of the populace . </P> <P> Samuel Colt neither invented nor perfected interchangeable parts, but his insistence (and other industrialists at this time) that his firearms be manufactured with this property, was another step towards the obsolescence of metal - working artisans and blacksmiths . (See also Eli Whitney). </P>

In which of the following process heat is created by blacksmith fire