Machine Tool

Machine Tool

In machine tools, a spindle is a rotating axis of the machine, which often has a shaft at its heart. The shaft itself is called a spindle, but also, in shop-floor practice, the word often is used metonymically 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 (whether wood lathe or metal lathe), the spindle is the heart of the headstock.

In rotating-cutter woodworking 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.


Types of Machine Tool Spindles: CNC Machine Spindles, Motorized Spindles, Multi Drill and Tap Head, Box and Cartridge spindles, Gear Driven Spindles, Belt Driven Spindles, Cluster Spindles, and any Specialty Spindles.


Spindle ball bearings are single-row angular contact ball bearings with a contact angle of 15° or 25° that can support load on one side. In respect of their design, their running accuracy and the materials used, they are optimised for highest speed and great bearing capacity.


Monton spindle ball bearings are characterised by the following properties:


Manufacture in grade P4 (or ABEC7) or better

Rings generally made of corrosion-resistant SV30 high-grade steel

Steel or ceramic balls available for all types

Machined solid retainer of fiber-reinforced phenolic resin or special materials, for example for applications involving higher temperatures

15° (C) or 25° (E) contact angle as a standard

Optionally, bearings can be paired with three pre-defined preload classes (L, M, S) or individual preload

Oil or grease lubrication

Open and closed versions available

Assembly, lubrication and packaging pursuant to cleanroom grade 10,000

Open spindle ball bearings


Standard version with large balls for optimum utilization of the bearing interior and solid retainer for high bearing capacity.

The outer ring has one shoulder only. The increased height of the snap feature prevents bearing collapse.

Solid retainer guided on outer ring with low cross-section, particularly well suited for oil injection lubrication.

Closed spindle ball bearings


The non-contact shields do not cause any additional friction torque

The standard shields made of Viton with metal stiffener offer excellent temperature and media resistance

Very narrow sealing gap for high dust protection

Recommended for grease lubrication, increases the longer service life

Same outer dimensions as open spindle bearings

This design requires often smaller balls, resulting in a lower bearing capacity but higher axial stiffness and speed limit (usually signified by an index letter after the basic type in the part number).

Also available without closure as high-speed version

Handling evidence:


Leave the bearing in its air-tight package until you are ready to start the assembly.

Ensure extreme cleanliness at the workplace.

Avoid shocks and impacts.

Axial load must only act on spindle bearings as indicated by the <s></s>marks on the outer ring.

Use suitable assembly tools to ensure that no assembly forces can be transferred through the balls.

Duplex bearings of pairing types -1 (DB), -2 (DF), -3 (DT) are always packed in pairs and can only be assembled in the specified arrangement with the other bearing in the package.

Universally matched bearings can be freely paired with each other, i.e. you may combine bearings from different packages or lots. These bearings may be assembled in any arrangement.

Before start of operation, allow the bearing to run in at high speed.



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