Page:Practical Treatise on Milling and Milling Machines.djvu/75

Rh  Attachments

A milling machine is, in itself, a most versatile tool, but when equipped with a suitable set of attachments, the range of work that can be done is greatly increased. Also there are often milling operations that can be performed without an attachment, but by using one the jobs can be more easily and quickly done. Attachments are, therefore, most desirable auxiliaries where a machine is not confined to one manufacturing operation, but is used for general milling purposes. And even in manufacturing, where a machine is kept on one operation, an attachment can often be used to good advantage.

Broadly speaking, the variety of attachments for use on milling machines is almost limitless. To fully realize this, one has only to visit several shops producing different kinds of work on milling machiens, and observe the methods employed. Devices of every conceivable description will be seen in use in connection with the machines, and, while many of them may be of a more or less special character and adaptable only to a particular operation, they are, strictly speaking, attachments. Some of these devices, however, are so designed that quite a number of different operations can be performed by their use, or the same operation can be repeated on a variety of pieces. It is these mechanisms that we are accustomed to regard more especially as attachments, while those designed for single operations are almost universally known in shops as fixtures. It would be useless to attempt to treat of the latter, as their designs and purposes are as varied as the different lines of mechanical work.

The efficency of attachments, like machines, depends largely upon their design and construction, and a poorly designed or built mechanism of this type can seriously impair the quality of work and thus defeat its own object.

Many forms of attachments designed for the same purpose will be found, as it is necessary for every manufacturer to adapt attachments to his machine. This is a matter of minor importance, however, and a close examination will reveal that, as a general rule, the principles of the different mechanisms are similar. This chapter is devoted to