Machine tool operators must be able to install or remove cutting bits or other accessories quickly and easily from the machine tool's powered rotating spindle. A lathe, for example, has a rotating spindle in its headstock, to which one may want to mount a spur drive or work in a collet. Another example is a drill press, to which an operator may want to mount a bit directly, or using a drill chuck. Virtually all milling machines, from the oldest, manual machines up to the most modern CNC machines utilize tooling that is piloted on a tapered surface. Conventional metalworking lathe In woodturning, metalworking, metal spinning, and glassworking, a lathe is a machine tool which spins a block of material so that when abrasive, cutting, or deformation tools are applied to the block, it can be shaped to produce an object which has rotational symmetry about an axis... A collet is a holding device that forms a collar around the object to be held and exerts a strong clamping force on the object when it is tightened. ... A CNC Turning Center A CNC Milling Machine The abbreviation CNC stands for Computer Numerical Control, and refers specifically to a computer controller that reads G-code instructions and drives the machine tool, a powered mechanical device typically used to fabricate metal components by the selective removal of metal. ...

Several options exist: (1) a threaded spindle, into/onto which accessories are screwed, (2) a permanently mounted chuck (as with some drill presses), or (3) a taper mount.

This simple, low-cost, and versatile tool mounting system involves (A) tool bits or holders with gradually tapered shanks, and (B) a matching hollowed-out spindle. Tools are simply slipped onto or into the spindle; the pressure of the spindle against the workpiece drives the tapered shank tightly into the tapered hole. The friction across the entire surface area of the interface provides a surprisingly large amount of torque transmission, so that splines or keys are not required. Torque applied via an adjustable end wrench Relationship between force, torque, and momentum vectors in a rotating system In physics, torque can informally be thought of as rotational force or angular force which causes a change in rotational motion. ...

This system is known as a machine taper.

Method of specification; overview of families

There are multiple different standard tapers, each differing in (a) the diameter at the small end of the truncated cone ("the minor diameter"); (b) the diameter at the large end of the truncated cone ("the major diameter"); (c) the axial distance between the two ends of the truncated cone.

The standards are grouped into families. One of the most widely used is the "Morse taper", which comes in 8 varieties, from "Morse 0" at 59.4 mm (2.34 inches) from end to end - to "Morse 7" at 295.3 mm (11.625 inches) from end to end.

It is noteworthy that even though one could design a family of tapers that all have the same included angle (e.g. the Foobar taper, from the 2" long Foobar-2 to the 100" long Foobar-100, all of which have a 5 degree included angle), the actual families of tapers in existence do not exhibit this design feature. Morse tapers, for example, taper at anywhere from 0.04988 inches of diameter per inch of length (for the Morse 1) to 0.05200 inches of diameter per inch of length (for the Morse 7).

One of the first uses of tapers was to mount drill bits directly to machine tools, although later drill chucks were invented that mounted to machine tools and in turn held non-tapered drill bits. Drill bits are cutting tools used to create cylindrical holes. ... A Chuck is a specialised type of clamp used to hold rotating tools or materials. ...

Details of use

Bits or accessories are inserted into a tapered receptacle and pushed or twisted into place. They are then held by friction.

Tapered shanks "stick" in tapers best when both the shank and the receptacle are clean. Shanks can be wiped clean, but receptacles, being deep and inaccessible, are best cleaned with a specialized taper cleaning tool which is inserted, twisted, and removed.

Tapered shank tools are removed from tapered receptacles either by inserting a drift punch axially from behind, and tapping the tapered shank tool out of the receptacle, or - if the tapered shank tool is so designed - inserting a wedge shaped block of metal called a "drift" into a rectangular shaped cross hole through the shank, and tapped. As the cross section of the drift gets larger when the drift is pushed further in, the result is that the drift, bearing against the foremost edge of the tang receptacle, pulls the tapered tang out.

Families of tapers

Morse

Morse Taper #2 (MT2)

The Morse Taper was invented by Stephen A. Morse (also the inventor of the twist drill) circa 1864. Since then it has evolved to encompass smaller and larger sizes and has been adopted as a standard by numerous organizations including ISO as ISO 296:1991 Machine Tools -- Self-Holding Tapers for Tools Shanks, and DIN as DIN 228-1:1987-05 Morse tapers and metric tapers; taper shanks. Image File history File links Download high resolution version (2048x1536, 1238 KB)Image of a Morse Taper #2, taken by Derrick Oswald. ... Image File history File links Download high resolution version (2048x1536, 1238 KB)Image of a Morse Taper #2, taken by Derrick Oswald. ... The International Organization for Standardization (ISO) is an international standard-setting body composed of representatives from national standards bodies. ... Look up din in Wiktionary, the free dictionary. ...

Morse Tapers come in eight sizes identified by number between 0 and 7. Often this is abbreviated as MT followed by a digit, for example a Morse taper number 4 would be MT4. The MT2 taper is the size most often found in drill presses up to 1/2" capacity.

Morse tapers can have two types of ends:

• tang (illustrated) to facilitate removal with a drift
• threaded to be held in place with a draw bar

The taper itself is roughly 5/8" per foot, but exact ratios and dimensions for the various sizes of tang type tapers are given below.

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Brown and Sharpe

Brown and Sharpe tapers are an alternate to the more-commonly seen Morse taper. Like the Morse, these have a series of sizes, from 1 to 18, with 7, 9 and 11 being the most common. Actual taper on these is within a close range of .500 per foot.

R8

collets with R8 taper

This taper was designed by Bridgeport Machines Inc. for use in their milling machines. It is used with a drawbar extending up through the spindle to the top of the machine to prevent the collet from falling from the spindle when lateral forces are encountered. The collet, which is inserted into the taper, has a precision hole in one end for holding a cutting tool and is threaded for a drawbar on other end. They are also keyed (see image) to prevent rotation, although for low cutting forces this may not always be needed. The drawbar thread is typically 7/16"-20tpi (UNF). Image File history File links Download high-resolution version (1332x1362, 294 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Machine taper User:Graibeard/gallery ... Image File history File links Download high-resolution version (1332x1362, 294 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Machine taper User:Graibeard/gallery ... The Unified Thread Standard (UTS) specifies the standard thread form, series, class, allowance, tolerance, and designation for unified screw threads. ...

The cutting tool is placed in the collet, the collet placed into the taper, and the drawbar is tightened into the top of the collet from above the spindle. The collet has a groove to engage a key in the spindle to keep the collet from spinning inside the taper and to aid in the installation and removal of the collet. The angle of the cone is typically 16 degrees and 51 minutes (i.e. 16.85 degrees) with an OD of 1.25" (source, Bridgeport Manufacturer).

Jacobs

The Jacobs Taper (abbreviated JT) is commonly used to secure drill press chucks to an arbor.

Jarno

Jarno tapers range from a Number 2 to a Number 20. The diameter of the big end in inches is always the taper size divided by 8, the small end is always the taper size divided by 10 and the length is the taper size divided by 2. For example a Jarno #7 measures 0.875" (7/8) across the big end. The small end measures 0.700" (7/10) and the length is 3.5" (7/2).

The system was invented by Oscar J. Beale of Brown & Sharpe manufacturing.

NMTB Tapers

The National Machine Tool Builders Association (now called the Association for Manufacturing Technology) laid down standards for machine tool design, among other things: the taper used on CNC (Computer Numerically Controlled) milling machines. Association for Manufacturing Technology, formerly the National Machine Tool Builders Association (NMTB), creates machine tool design standards. ...

The taper is variously referred to as NMTB, NMT or NT. Essentially this defines a taper of 3.500 inches per foot. All NMTB Tooling has this taper but the tooling comes in different sizes. NMTB-25, 30, 35, 40, 45, 50 and 60. With the 40 taper being the most common by far.

CAT and BT tooling use this same taper.

For historical reference: This is the same taper as that found on an R8 Collet. The R8 collet precedes NMTB tooling as the toolholder of choice for milling machines. A collet is a holding device that forms a collar around the object to be held and exerts a strong clamping force on the object when it is tightened. ...

The goal of the taper is to allow a quick and easy change between different tools (either automatically or by hand) and still keep it tight and centered while using it. The spindle on the machine tool is built with a female taper and drawbar. Each individual tool must be fitted with a male taper and the proper adapter for the drawbar.

NT 40 (int40)

NT 50 (int50)

External links

• Beautiful Iron Overview of Tapers

• Quickly Identify your Morse Taper

Metalworking:
Machine tooling: Image File history File links Blacksmith-hammer-anvil-50x50. ... This article or section is in need of attention from an expert on the subject. ...	Angle plate | Chuck | Collet | Fixture | Indexing head | Lathe center | Machine taper | Magnetic base | Mandrel | Rotary table | Wiggler Adjustable angle plate Fixed angle plate An angle plate is a work holding device used as a fixture in metalworking. ... A Chuck is a specialised type of clamp used to hold rotating tools or materials. ... A collet is a holding device that forms a collar around the object to be held and exerts a strong clamping force on the object when it is tightened. ... Indexing head and tailstock set up on a milling machines table An indexing head is a specialized tool that allows a work piece to be rotated to any angle angle or circular division. ... A lathe center (or center) is a tool that has been ground to an included angle of 60 ° and is used to accurately position a workpiece about its axis. ... Magnetic base as used in the engineering metaltrades. ... Mandrel (pronounced mandrul, and also transliterated as manderil) is a term that can refer to: an object used to shape machined work; a tool component that grips or clamps materials to be machined; or a tool component that can be used to grip other moving tool components. ... 10 inch, manual rotary table A rotary table is a precision work positioning device used in metalworking. ... Wiggler Set of wigglers A wiggler, center finder or sticky pin refers to a tool used in the rotating spindle of a machine such as mill or drill. ...
Metalworking topics:   Casting | CNC | Cutting tools | Drilling and threading | Fabrication | Finishing | Grinding | Jewellery | Lathe (tool) | Machining | Machine tooling | Measuring | Metalworking | Hand tools | Metallurgy | Milling | Occupations | Press tools | Smithing | Terminology | Welding This article or section is in need of attention from an expert on the subject. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... A CNC Turning Center A CNC Milling Machine The abbreviation CNC stands for Computer Numerical Control, and refers specifically to a computer controller that reads G-code instructions and drives the machine tool, a powered mechanical device typically used to fabricate metal components by the selective removal of metal. ... a Cutting Tool, in the context of Metalworking is any tool that is used to remove metal from the workpiece by means of shear deformation. ... Drilling is the process of using a drill bit in a drill to produce holes. ... A typical steel fabrication shop Fabrication is an industrial term generally applied to the building of metal machines and structures. ... Metalworking finishing is the activity of making things out of metal in a skillful manner. ... Rotating abrasive wheel on a bench grinder. ... Jewellery (jewelry in American English) is any piece of fine material used to adorn the human body. ... Conventional metalworking lathe In woodturning, metalworking, metal spinning, and glassworking, a lathe is a machine tool which spins a block of material so that when abrasive, cutting, or deformation tools are applied to the block, it can be shaped to produce an object which has rotational symmetry about an axis... A lathe is a common tool used in machining. ... A machine tool is a powered mechanical device, typically used to fabricate metal components of machines by the selective removal of metal. ... The examples and perspective in this article or section may not represent a worldwide view. ... This article or section is in need of attention from an expert on the subject. ... Metalworking hand tools are hand tools that are used in the metalworking field. ... Metallurgy is a domain of materials science and of materials engineering that studies the physical and chemical behavior of metallic elements, their intermetallic compounds, and their mixtures, which are called alloys. ... Cutters for a milling machine. ... It has been suggested that this article or section be merged with Smith (metalwork). ... Power press with a fixed barrier guard A press, or a machine press is a tool used to work metal (typically steel) by changing its shape and internal structure. ... A smith, or metalsmith, is a person involved in the shaping of metal objects. ... This article needs to be wikified. ... Welding is a fabrication process that joins materials, usually metals or thermoplastics, by causing coalescence. ...