Milling Machine Attachments and Accessories
Points : Milling Machine Attachments and Accessories, Dividing Head, Mechanism of dividing head, Vertical Head, Rotary Head, Slotting Attachment, Rack Cutting Attachment
By means of various attachments, which have come to be recognized as practically standard equipment for the column and knee type milling machine, many jobs can be done more quickly and conveniently than otherwise, and, in addition, a large variety of operations may be performed on one machine which, without the attachments, would require several kinds of machines.
The manufacturers of milling machines furnish attachments at are interchangeable on their own make of machines of the same size, and many of these attachments, especially those which are clamped to the table, may be used on different sizes of machines or even on different makes of machines. The intelligent use of such attachments makes for increase operating efficiency, convenience, and accuracy. The following attachments are commonly used on milling machines for different operations. (a) Dividing Head An important use of the milling machine is for cutting slots, grooves, teeth, etc; which are to be spaced round the circumference of a cylinder or dip. Examples of such work are given by the teeth of gears, ratchet wheels, milling cutter blanks, reamers and so on. Milling of this nature necessitates the assistance of sonic means of holding the work, and rotating it the correct amount for each groove or slot to be cut. The degree of accuracy to which the spacing must be made is important. To adopt the milling machine for the purposes a dividing head is used. A dividing head is also called an index head, is a device used to divide the periphery of a piece of work into any number of equal or unequal parts and to hold the Work in the required position while the cuts are being made. The dividing head is sometimes called the spiral head; since it is also used for the purpose of holding and turning work while helical grooves are being milled, as in twist drills and helical gears. Mechanism of dividing head Mechanism of dividing head The worm wheel has 40 teeth and the worm has single thread. The worm wheel is keyed to the spindle and when the worm which is turned by the index crank is turned 40 times the spindle is revolved one. Fractional parts of a turn are obtained by means of an index elate, sector arms are used to mark of the number of holes on the index plate. Following three types of indexing ‘or dividing beads are used on milling machine.
1. Plain Dividing Head
2. Universal Dividing Head
3. Optical Dividing Head (b) Vertical Head The spindle in this attachment can be set and securely clamped at any angle in a vertical plane, the position being indicated by graduations in degrees. This attachment offers an easy means of doing work which would be inconvenient to do with the cutter held in the main spindle and, more important, makes it possible to produce work that would otherwise require a vertical spindle milling machine. (c) Rotary Head This device attached to machine column by a suitable bracket and having a spindle independently driven through a flexible cable, is intended for use with small diameter cutters. The normally vertical cutting spindle axis can be set at any angle up to 150 from the vertical and, through a lateral cross slide, can be offset from the vertical axis of graduated swivel base which can be manually rotated through any number of degrees. (d) Slotting Attachment This equipment, mounted on the machine column, and driven by the machine spindle, converts rotary motion into reciprocating motion of adjustable stroke length. The mechanism is mounted on a graduated circular swivel base, permitting reciprocating motion at any angle in the vertical plane parallel to the column face. One end of the sliding ram accepts single-point slotting tools of any practical form. Among other things this attachment is used for cutting internal or external key-ways, splines, serrations, blind holes, cavities, or gears, particularly in which consist of various sizes of rounds, squares, and special shapes is furnished with the attachment. These tools have squares rectangular or cylindrical shanks and are secured in the holder by means of a set screw. (e) Rack Cutting Attachment This is almost indispensable attachment if racks more than 10 or 12 inch are to be cut. The cutter is mounted on the end of a hardened-steel spindle, which is driven parallel to the table T-slots by spur and bevel gears. At the left of the vise for holding the rack may he seen the rack indexing attachment. It consist of a bracket fastened to the table and carrying change gears for gearing to the feed screw, and a locking disc, When it is properly geared, one or more whole turns of the disc, to a locking pin, will advance the table an amount equal to the pitch of the rack tooth.
The manufacturers of milling machines furnish attachments at are interchangeable on their own make of machines of the same size, and many of these attachments, especially those which are clamped to the table, may be used on different sizes of machines or even on different makes of machines. The intelligent use of such attachments makes for increase operating efficiency, convenience, and accuracy. The following attachments are commonly used on milling machines for different operations. (a) Dividing Head An important use of the milling machine is for cutting slots, grooves, teeth, etc; which are to be spaced round the circumference of a cylinder or dip. Examples of such work are given by the teeth of gears, ratchet wheels, milling cutter blanks, reamers and so on. Milling of this nature necessitates the assistance of sonic means of holding the work, and rotating it the correct amount for each groove or slot to be cut. The degree of accuracy to which the spacing must be made is important. To adopt the milling machine for the purposes a dividing head is used. A dividing head is also called an index head, is a device used to divide the periphery of a piece of work into any number of equal or unequal parts and to hold the Work in the required position while the cuts are being made. The dividing head is sometimes called the spiral head; since it is also used for the purpose of holding and turning work while helical grooves are being milled, as in twist drills and helical gears. Mechanism of dividing head Mechanism of dividing head The worm wheel has 40 teeth and the worm has single thread. The worm wheel is keyed to the spindle and when the worm which is turned by the index crank is turned 40 times the spindle is revolved one. Fractional parts of a turn are obtained by means of an index elate, sector arms are used to mark of the number of holes on the index plate. Following three types of indexing ‘or dividing beads are used on milling machine.
1. Plain Dividing Head
2. Universal Dividing Head
3. Optical Dividing Head (b) Vertical Head The spindle in this attachment can be set and securely clamped at any angle in a vertical plane, the position being indicated by graduations in degrees. This attachment offers an easy means of doing work which would be inconvenient to do with the cutter held in the main spindle and, more important, makes it possible to produce work that would otherwise require a vertical spindle milling machine. (c) Rotary Head This device attached to machine column by a suitable bracket and having a spindle independently driven through a flexible cable, is intended for use with small diameter cutters. The normally vertical cutting spindle axis can be set at any angle up to 150 from the vertical and, through a lateral cross slide, can be offset from the vertical axis of graduated swivel base which can be manually rotated through any number of degrees. (d) Slotting Attachment This equipment, mounted on the machine column, and driven by the machine spindle, converts rotary motion into reciprocating motion of adjustable stroke length. The mechanism is mounted on a graduated circular swivel base, permitting reciprocating motion at any angle in the vertical plane parallel to the column face. One end of the sliding ram accepts single-point slotting tools of any practical form. Among other things this attachment is used for cutting internal or external key-ways, splines, serrations, blind holes, cavities, or gears, particularly in which consist of various sizes of rounds, squares, and special shapes is furnished with the attachment. These tools have squares rectangular or cylindrical shanks and are secured in the holder by means of a set screw. (e) Rack Cutting Attachment This is almost indispensable attachment if racks more than 10 or 12 inch are to be cut. The cutter is mounted on the end of a hardened-steel spindle, which is driven parallel to the table T-slots by spur and bevel gears. At the left of the vise for holding the rack may he seen the rack indexing attachment. It consist of a bracket fastened to the table and carrying change gears for gearing to the feed screw, and a locking disc, When it is properly geared, one or more whole turns of the disc, to a locking pin, will advance the table an amount equal to the pitch of the rack tooth.
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