Page:Practical Treatise on Milling and Milling Machines.djvu/77

Rh our line of attachments, as typical of attachments in general, with brief descriptions of their general designs and functions. From this information it is hoped that the reader will be able to understand the necessity for, and advantages of, these mechanisms.

Vises. While vises are furnished as a part of the regular equipment of most milling machines, and for that reason are not styled as attachments, notwithstanding this, they may be so properly classed.

Vises are useful for holding a large variety of small work while it is being milled or planed. Numerous illustrations of their employment can be found in the examples of operations throughout Chapters VII and IX. It is essential that they be as rigid as possible, and to this end should be built with well-designed, strong, close-fitting parts. It is well to have them set low so as to bring the work close to the table.

There are several styles of vises. Fig. 18 shows a Plain Vise, for lighter operations. The bed and slide are of cast iron, while the jaws are tool steel, hardened and ground. It is fastened to the surfaces of the table by means of a screw that passes through the bed and threads into a nut inserted in a table T slot. The head of th eclamping screw fits a counterbore in the vise bed, and is flush with the top of the casting, so that it does not interfere with the movement of the sliding jaw.

The vise shown in Fig. 19 is known as a Flanged Vise, adn differs little from the Plain Vise except in the method of clamping to the table. A slotted flange is provided at each end for this purpose, and regular T slot bolts with nuts and washers are employed. Also a pair of straps are furnished for clamping the vise at the sides when this is necessary.

It is sometimes desired to mill angular or tapering work. A vise provided with a swivel, and known by that name, is shown in Fig. 20, and by its use this work can be readily done. The vise proper is of the same design as the plain vise, but the bottom of the bed fits into a split ring in a base. This ring is tapered on the inside to draw the bed to its seat, and holds it rigidly without disturbing the alignment. The split ring is closed by either one of the two clamping bolts at the side, two being provided for convenience in setting. The entire circumference of the base is graduated to degrees, and the vise can be readily swung to any angle to the table ways. The base is provided with flanges for fastening it to the surface of the table.

Fig. 21 shows a Tool Makers' Universal Vise, designed to meet the requirements of tool makers and machine shops where a great