Machine Manufacturing. While machine work in general, and the use of machine tools in particular are much the same in all shops, the methods employed in machine building and in machine manufacturing are essentially different.
In machine building only a small number of machines are built in a single lot and it is seldom that they are worked upon in any consecutive order. For example, while several machines of the same kind may be under construction, they may stand in all stages of construction from that of those nearing completion or even completed to some upon which construction has just begun. In some shops, this is so much the fact that machines are constructed only after the order for them has been placed. When manufacturing machines, however, the process is a very different one. Here the work is done in lots of considerable size and each operation on each piece is consecutively performed.
The workmen in a shop producing machines by manufacturing methods are differently placed than they are in shops building machines in small lots, perhaps a machine at a time only. In the latter case the workmen may, during the same day, perform lathe work, milling, drilling, bench, and floor work; while in a shop which manufactures machines in considerable lots, the workmen usually works on one machine during the term of employment. This has led to the development of workmen who term themselves lathe hands, planer hands, etc., each workman specializing in the handling of a single machine tool and seeking employment as a specialized machinist. In certain shops, notably those building automobiles, this specializing process has proceeded to such an extent that the workman performs but a single operation on a machine. For example, he may be employed on a lathe to square up the end of crank shafts, which come to him in sufficient quantities to keep him continuously employed during his working day. If the shop is run on a twenty-four hour, three-shift basis, he may in this case be one only, of three workmen, each of whom does the same operation on the same single purpose machine.
If the reader has carefully followed the above, he will realize somewhat the extent to which modern organization of workmen has proceeded. Another development has been the construction of single purpose machines. For example, Fig. 350, page 294, shows a machine constructed for the single purpose of drilling the clearance holes on solid threading dies. On this machine a single operation only can be performed, but by the use of four spindles and five work-holding chucks, a die is completely finished at one stroke of the table. Single purpose machine tools of any sort can now be bought in the open market, as, for example, single purpose lathes, grinding machines, etc.
In other cases, instead of purchasing single purpose machines, the regular types have been changed by the use made of special attachments, tools, jigs, and fixtures, to perform either a single operation only, or at least a slight range of operation.