Detailed illustration of CNC tool holder standard

CNC milling machine and boring and milling machine center use 7:24 tool taper shank most. But in high-speed machine tools, the use of 1:10 hollow short taper shank is increasing. For turning centers and turning and milling centers, 1:10 short taper shank is used more frequently (CZG cylindrical shank tool system used in turning centers is not the scope of this paper).

The standard of 7:24 tool taper shank commonly used in automatic tool changing machine tools is as follows:
First, China National Standard GB 10944-89 "7:24 tapered tool shank 40, 45 and 50 tapered shank for automatic tool changing machine tools";
The Chinese national standard GB 10944-89 of 7:24 tool taper shank for automatic tool changing machine tool is formulated with reference to the international standard ISO 7388/1:1983. Except for rounding the data of very few items (such as the bottom hole depth of the tail thread 13) or unspecified data (such as the chamfer of the key groove on the flange), the other data are identical. The shape size is the same, which can be divided into two types: type A and type B. The angle of the tension plane of type A is 15 degrees, which is used for the tension device without steel ball, code name is "LDA". The angle of the tension plane of type B is 45 degrees, which is used for the tension device with steel ball, code name is "LDB". Both have through holes for cooling fluid circulation.
Common standards of 7:24 tool taper shank for manual tool change include national standard GB 3837.3-83 and international standard ISO 297-82, and mechanical industry standard JB 3381.1-83. 1:10 hollow tool taper shank has national standard GB 19449.1-2004 "hollow taper interface with flange contact surface"

Second, international standards ISO 7388/1:1983 (tool taper shank No. 40, 45 and 50) and ISO 7388/3:1986 (tool taper shank No. 30);
The international standard ISO 7388/1:1983 is formulated with reference to the German standard DIN 69871-1 A tool taper handle, so the three standards have the same shape and size. In China, the code name of the tool taper handle is "JT". Its features are: the flange thickness is small; there is a positioning gap for a knife; two end keyways are asymmetrically distributed.

Thirdly, the German standard is DIN 69871-1:1995 (tool taper handle No. 30, 40, 45, 50 and 60) and DIN 69871-2 (tool taper handle No. 40, 45, 50, 55 and 60).
The taper shank of 7:24 tool for automatic tool changing machine tool is divided into three types in German standard DIN 69871-1: A type, AD type and B type: A type is not connected with the bottom hole of thread; AD type is connected with the bottom hole of thread; B type is supplied with water for the end face of flange. However, DIN 69871-2 has only one type of C, double parallel flanges and no V-groove. It is seldom used now. Although the tool taper handle code is not specified in the standard, it is usually called "SK" in Germany.
The former German standard DIN 69893-1:1996 has been replaced by the new standard DIN 69873-1:2003, and the new German standard is equivalent to the content of the international standard ISO 12164-1:2001. Other common structures of 1:10 tool taper shank basically adopt enterprise standards, such as KM series of Kenner Company in the United States, Capto series of Sandvik Company in Sweden, NOVEX series of Walter Company in Germany, etc.
German standard DIN 6988-1987 has two kinds of pulling nails, type A with through hole, type B without through hole, but with ring groove for sealing ring to prevent leakage of coolant from the tail. The inclined angles of the tension surfaces of the two kinds of nails are both 15 degrees, which are used for tension devices without steel balls.

Fourthly, the current standard of Japan is JIS B 6339:1998 (No. 30, 35, 40, 45, 50, 55 and 60 tool taper shank), which is used to replace the standard MAS-403:1975 (No. 40, 45, 50 and 60 tool taper shank) of Japan Working Machinery Association.
Although the Japanese standard JIS B 6339:1998 for 7:24 tool taper shank of automatic tool changing machine tool has replaced the standard MAS-403:1975 of Japan Working Machinery Association, it has little effect on the use because of the same main shape and size, so the standard code MAS-403 is still marked on the samples of many manufacturers, but JIS B 6339 is not marked. It should be noted, however, that the two standards use different pull nails. Its tool taper shank code is "BT", which is characterized by large flange thickness, asymmetrical distribution of V-groove near the side of the working part, symmetrical distribution of two end keyways and non-milling of end keyways.

The Japanese standard JIS B 6339:1998 has only one type of pulling nail. The angle of the pulling surface of the pulling nail is 15 degrees. It is used for the pulling device without steel balls. The code name is "xxP". The standard MAS-403 of Japan Working Machinery Association has two types: type I and type II. The angle of tension plane of type I is 30 degrees, which is used for tension device without steel ball; type II is 45 degrees, which is used for tension device with steel ball. When using, it should be noted that the head length of these two kinds of pull nails is smaller than that of JIS B 6339:1998 standard, and the neck length is longer. Its code name is "PxxT".

Fifth, the current standard in the United States is AMSE B5.50-1994 (No. 30, 40, 45, 50 and 60 tool taper handle), which is used to replace ANSI/AMSE B5.50-1985 standard.
American standard AMSE B5.50-1994 for 7:24 tool taper shank of automatic tool changing machine tool has replaced ANSI/AMSE B5.50-1985. Similarly, because of the same shape and size, many manufacturers still label ANSI/AMSE B5.50 on samples or only ANSI. Although the tool taper handle code is not specified in the standard, it is usually called "CAT", which is characterized by smaller flange thickness, asymmetric distribution of two end keyways, and drilling identification holes on the bottom of one end keyway for tool positioning. The tail threads should be UNC threads. For the convenience of users, the domestic manufacturers should change the tail threads to the corresponding metric threads with the other sizes unchanged.
American standard AMSE B5.50-1994 has only one type of pull nail, and the angle of pull nail's tension plane is 45 degrees.