machine tool A machine tool is a machine for handling or machining metal or other rigid materials, usually by cutting, boring, grinding, shearing, or other forms of deformations. Machine tools employ some sort of tool that does the cutting or shaping. Al ...

s, a spindle is a rotating axis of the machine, which often has a

shaft Shaft may refer to: Rotating machine elements * Shaft (mechanical engineering), a rotating machine element used to transmit power * Line shaft, a power transmission system * Drive shaft, a shaft for transferring torque * Axle, a shaft around whi ...

at its heart. The shaft itself is called a spindle, but also, in shop-floor practice, the word often is used

metonymically Metonymy () is a figure of speech in which a concept is referred to by the name of something closely associated with that thing or concept. Etymology The words ''metonymy'' and ''metonym'' come from grc, μετωνυμία, 'a change of name' ...

to refer to the entire rotary unit, including not only the shaft itself, but its bearings and anything attached to it ( chuck, etc.). A machine tool may have several spindles, such as the headstock and tailstock spindles on a bench lathe. The main spindle is usually the biggest one. References to "the spindle" without further qualification imply the main spindle. Some machine tools that specialize in high-volume mass production have a group of 4, 6, or even more main spindles. These are called multispindle machines. For example, gang drills and many screw machines are multispindle machines. Although a bench lathe has more than one spindle (counting the tailstock), it is not called a multispindle machine; it has one main spindle. Examples of spindles include * On a

lathe A lathe () is a machine tool that rotates a workpiece about an axis of rotation to perform various operations such as cutting, sanding, knurling, drilling, deformation, facing, and turning, with tools that are applied to the workpiece ...

(whether wood lathe or metal lathe), the spindle is the heart of the

headstock A headstock or peghead is part of a guitar or similar stringed instruments such as a lute, mandolin, banjo, ukulele and others of the lute lineage. The main function of a headstock is to house the pegs or mechanism that holds the strings at th ...

. * In rotating-cutter

woodworking Woodworking is the skill of making items from wood, and includes cabinet making (cabinetry and furniture), wood carving, joinery, carpentry, and woodturning. History Along with stone, clay and animal parts, wood was one of the first mate ...

machinery, the spindle is the part on which shaped milling cutters are mounted for cutting features (such as rebates, beads, and curves) into mouldings and similar millwork. * Similarly, in rotating-cutter metalworking machine tools (such as milling machines and drill presses), the spindle is the shaft to which the tool (such as a drill bit or milling cutter) is attached (for example, via a chuck). * Varieties of spindles include grinding spindles, electric spindles, machine tool spindles, low-speed spindles, high speed spindles, and more. File:HwacheonCentreLathe-headstock-mask legend.jpg, Lathe headstock: H4 - Spindle File:HwacheonCentreLathe-tailstock-mask legend.jpg, Lathe tailstock: T5 - Spindle File:Multi spindle lathe 2.JPG, Multi spindle lathe File:Milling machine (Vertical, Manual) NT.PNG, Vertical milling machine (single spindle): #2 - Spindle

High speed spindle

High speed spindles are used strictly in machines, like CNC mills, designed for metal work. There are two types of high speed spindles, each with different designs:

Belt-driven spindle

Consisting of spindle and bearing shafts held within the spindle housing, the belt-driven spindle is powered by an external motor connected via a belt-pulley system. * External Motor: can be changed to create higher power and torque * Max speeds: 12,000-15,000 RPM * Advantage: cost effective * Disadvantage: limited max speed limits applications

Integral motor spindle

A main component of this spindle is the motor, stored internally. * Internal Motor: limited power and torque due to restricted space within the spindle housing * Speed Range: 20,000-60,000 RPM (top speed according to design) * Advantage: high top speed expands application use * Disadvantage: sensitive life range according to use Both types, the belt-driven and the integral motor spindles, have advantages and disadvantages according to their design. Which one is more desirable depends on the purpose of the machine and product(s) being produced.

References

External links

* Machine tools {{woodworking-stub de:Spindel io:Spindelo