The factors that drove Birmingham's rapid industrialisation were also different from those behind the later development of textile manufacturing towns such as Manchester, whose spectacular growth from the 1780s onwards was based on the economies of scale inherent in mechanised manufacture: the ability of a low-wage, unskilled labour force to produce bulk commodities such as cotton in huge quantities. Although the developments that enabled this transformation – roller spinning, the factory system and the industrial steam engine – often had Birmingham origins, they had little role in Birmingham's own expansion. Birmingham's relatively inaccessible location meant that its industries were dominated by the production of a wide variety of small, high value metal items – from buttons and buckles to guns and jewellery. Its economy was characterised by high wages and a diverse range of specialised skills that were not susceptible to wholesale automation. The small-scale workshop, rather than the large factory or mill, remained the typical Birmingham manufacturing unit throughout the 18th century, and the use of steam power was not economically significant in Birmingham until the 1830s.