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In the design of machine tools there is a need for users to be able to quickly and easily install or remove particular cutting bits or other accessories from the powered rotating spindle of the machine tool. One example is a lathe headstock, which has a rotating spindle to which one may want to mount a spur drive. Another example is a drill press on which one may want to mount a bit, a chuck, etc. This article is about a lathe as a tool. ...
Several options exist: the machine tool can present a threaded spindle, to which accessories are screwed. The machine tool may have a permanent chuck. A simple, low cost, and versatile option is to hollow out a truncated conical void in the rotating spindle, coaxial with the axis of rotation. Tools or accessories can then have a mating male conical shaped shank, which precisely fits into the void. The pressure of the spindle against the workpiece serves to drive the tapered shank tightly into the tapered receptable. The friction across the entire surface area of the interface provides a suprisingly large amount of torque transmission, so that splines or keys are not required.
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. The most famous family 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 the cutters of drill tools. ...
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 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. ...
Logo of the International Organization for Standardization The International Organization for Standardization (ISO or iso) is an international standard-setting body composed of representatives from national standards bodies. ...
Deutsches Institut für Normung (DIN, the German Institute for Standardization) is a German national organization for standardization. ...
Morse tapers come in eight sizes identified by number -- #0 through #7. Often this is abbreviated as MT followed by a digit, for example a Morse taper number 4 would be MT4.
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. Morse Taper Dimensions (mm) |
 Image File history File links Diagram illustrating Morse Taper critical dimensions. ...
| Morse Taper
| Taper
| A
| B (max)
| C (max)
| D (max)
| E(max)
| F
| G
| H
| J
| K
| 0
| 19.212:1
| 9.045
| 56.5
| 59.5
| 10.5
| 6
| 4
| 1
| 3
| 3.9
| 1°29'27"
| 1
| 20.047:1
| 12.065
| 62
| 65.5
| 13.5
| 8.7
| 5
| 1.2
| 3.5
| 5.2
| 1°25'43"
| 2
| 20.020:1
| 17.780
| 75
| 80
| 16
| 13.5
| 6
| 1.6
| 5
| 6.3
| 1°25'50"
| 3
| 19.922:1
| 23.825
| 94
| 99
| 20
| 18.5
| 7
| 2
| 5
| 7.9
| 1°26'16"
| 4
| 19.254:1
| 31.267
| 117.5
| 124
| 24
| 24.5
| 8
| 2.5
| 6.5
| 11.9
| 1°29'15"
| 5
| 19.002:1
| 44.399
| 149.5
| 156
| 29
| 35.7
| 10
| 3
| 6.5
| 15.9
| 1°20'26"
| 6
| 19.180:1
| 63.348
| 210
| 218
| 40
| 51
| 13
| 4
| 8
| 19
| 1°29'36"
| 7
| -
| 83.058
| 285.75
| 294.1
| 34.9
| -
| -
| 19.05
| -
| 19
| 1°29'25"
|
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 Bridgeport designed this for their milling machines. It is used with a drawbar extending up through the spindle to the top of the machine. Collet has a precision hole in one end for holding cutter and is threaded for drawbar on other end. Thread is typically 7/16"-20tpi. Cutter is placed in collet and drawbar is tightened on top of machine with wrench. Collet has grove to engage key in spindle to keep from slipping and aid in installation and removal of collet. The angle of the cone is typically 16 degrees and 51 minutes (i.e. 16.85 degrees) with on OD of 1.25" (source, Bridgeport Manufacturer).
Jacobs The Jacobs Taper (abbreviated JT) is commonly used to secure drill press chucks to an arbor.
NT 30 (int30)
NT 40 (int40)
NT 50 (int50)
External Links Beautiful Iron Overview of Tapers
 WikiProject Metalworking:
| | Machine tooling: Image File history File links Blacksmith-hammer-anvil-50x50. ...
Metalworking is the craft and practice of working with metals to create parts or structures. ...
| Angle plate | Chuck | Collet | Fixture | Indexing head | Lathe center | Machine tapers | 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 items 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. ...
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Metalworking topics: Casting | CNC | Cutting machines | Cutting tools | Drilling and threading | Fabrication | Finishing | Grinding | Jewellery | Lathes | Machining | Machine tooling | Measuring | Metalworking | Hand tools | Metallurgy | Milling | Occupations | Press tools | Smithing | Terminology | Welding Casting is a process by which a material is introduced into a mold while it is liquid, allowed to solidify in the shape inside the mold, and then removed producing a fabricated object, part, or casing. ...
A CNC Turning Center The abbreviation CNC stands for Computer(ized) Numerical(ly) Control(led), and refers specifically to the computer control of machine tools for the purpose of (repeatedly) manufacturing complex parts in metal as well as other materials, using a program written in a notation conforming to the...
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. ...
Rotating abrasive wheel on a bench grinder. ...
Jewellery (Jewelry in American spelling); consists of ornamental devices worn by persons, typically made with gems and precious metals. ...
This article is about a lathe as a tool. ...
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. ...
Metalworking is the craft and practice of working with metals to create parts or structures. ...
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 and their mixtures, which are called alloys. ...
A Milling machine is a power-driven machine used for the complex shaping of metal (or possibly other materials) parts. ...
A press, or a machine press is a tool used to shape metal (typically steel) by bending it. ...
A smith or metalsmith is a person involved in the shaping of metal objects. ...
Welding is a fabrication process that joins materials, usually metals or thermoplastics, by causing coalescence. ...
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