C281 Hematite Vein

Although Tian Cheng was not that professional when it came to mechanical manufacturing, he was definitely not an amateur. Back then when he made the marmot capturing cages, he had used some simple mechanical principles, after all, he was a doctor from the modern world, right? In the past, he had been immersed in his research. Now that he saw this old man, he seemed to have found his own shadow