Page:On the economy of machinery and manufactures - Babbage - 1846.djvu/223

Rh necessary to ascertain:1. The defects to which pins so made are liable. 2. Their advantages, if any, over those made in the usual way. 3. The prime cost of the machine for making them. 4. The expense of keeping it in repair. 5. The expense of moving the machine and of attending to it.

1. Pins made by the machine are more likely to bend, because the head being "punched up," the wire must be in a soft state to admit of that operation. 2. Pins made by the machine are better than common ones, because they are not subject to losing their heads. 3. With respect to the prime cost of a machine, it would be very much reduced if a large number should be required. 4. With regard to its wear and tear, experience only can decide: but it may be remarked, that the steel clams or dies in which the heads are punched up, will wear quickly unless the wire has been softened by annealing; and that if softened, the bodies of the pins will bend too readily. Such an inconvenience might be remedied, either by making the machine spin the heads and fix them on, or by annealing only that end of the wire which is to become the head of the pin: but this would cause a delay between the operations, since the brass is too brittle, while heated, to bear a blow without crumbling. 5. On comparing the time occupied by the machine with that stated in the analysis, we find that, except in the heading, the human hand is more rapid. Three thousand six hundred pins are pointed by the machine in one hour, whilst a man can point fifteen thousand six hundred in the same time. But in the process of heading, the rapidity of the machine is two and a half times that of the human hand. It