Bach needed eight years to finish his diploma (1864-1872), with many interruptions, as he was constantly short of money.
A present of money from his grandmother allowed him to start studying in Chemnitz. After a break of almost two years a craftsman lent him money so that he could take up his studies again in Dresden. He then followed his teacher Kankelwitz to the Polytechnic in Stuttgart, again to earn money assisting him in practical construction courses for younger students. After serving in the Franco-German War of 1870/71 he finally received his diploma at the Polytechnic in Karlsruhe in 1872.