was at work which made these spikes, each weighing ½lb., at the rate of 50 per minute. They are packed in kegs, each containing 300. Seven men only are employed on the works, and they manufacture 5 tons of spikes per day.
11. Nails and Rivets.—In another establishment at Pittsburgh, 250 men are employed in manufacturing bar iron, rods, sheets, and nails. The iron is manufactured both with anthracite coal and charcoal.
They have fifty-one machines for making cut nails; many of them are self-acting in the feeding for the smaller sizes; the strip of iron is inserted in a tube, which is made to revolve alternately half round each way.
They make 2,000 kegs of such nails per week, each weighing 100 lbs., and containing sizes from fourpenny up to tenpenny nails.
A rivet-making machine was at work, which made rivets weighing seven to the pound, at the rate of eighty per minute. Its main shaft carried two cams, one a side cam which gave the motion for cutting off and holding the iron between the dies, the other a direct cam for forming the head of the rivet.
The cams for the nail machines are made of chilled cast iron, and that part of the lever which acts against the cam is faced with a plate of