Page:Practical Treatise on Milling and Milling Machines.djvu/88

82 is adapted for use upon vertical spindle machines, or horizontal spindle machines in connection with the vertical spindle milling and slotting attachments. It has no automatic feed. When used with the vertical spindle milling attachment, the machine is fitted for all varieties of straight, surface and circular milling within its capacity, and with the slotting attachment, for all kinds of slotted work, such as die making, making templates, splining keyways, etc. Its design embodies the same features as the ones just Fig. 36 described, and, in addition, the index finger on the front of the attachment is adjustable to allow readings to be taken from any convenient graduation, and an adjustable dial graduated to read to 5 minutes, is fixed to the worm shaft. An index table mounted on the front of the base gives the degrees required for setting the table to produce work with 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 16, 18, 20 and 24 sides. This is particularly valuable for use in connection with the slotting attachment.

High Speed Milling Attachment. Sometimes it is necessary in doing such work as milling keyways and slots, die making, etc., to use a small cutter, which should be run more rapidly than the fastest spindle speed available, otherwise it limits the production and is liable to be broken in feeding. In order to obtain correct speeds for these small mills, high speed milling attachments are employed. Fig. 36 shows one of these attachments for use on a vertical spindle milling machine, and Fig. 37 one designed for