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

    Automatic tool changer commonly used 7:24 tool taper shank standards are: 

 First, China's national standard GB 10944-89 “automatic tool changer with 7:24 taper tool shank 40, 45 and 50 taper shank”; 

 Automatic tool changer with 7:24 tool taper shank of Chinese National standard GB 10944-89 is a reference
to the use of international standards ISO 7388/1: 1983 developed, in addition to very few items of data rounded
(such as the end of the thread depth of the bottom hole 13) or unspecified data
(such as the keyway on the flange chamfering at the root), the other data is exactly the same.
Dimensions are the same, divided into A and B type two: A type spigot tension surface bevel angle of 15 °,
for tensioning devices without steel ball, code for “LDA”; B type spigot tension surface bevel angle of 45 °,
for tensioning devices with steel ball, code for "LDB LDB". Both with through holes for coolant flow.

    The common standards for 7:24 tool taper shank for manual tool change are national standard GB 3837.3-83 and international standard ISO 297-82,
as well as the machinery industry standard JB 3381.1-83. 1:10 hollow tool taper shank has been
the national standard GB 19449.1-2004 "with flange contact surface of the hollow cone interface 

 two, the international standard ISO 7388/1: 1983 (40, 45 and 50 tool taper handle) and ISO 7388/3: 1986 (30 tool taper handle); 

 international standard ISO 7388/1: 1983 and International standard ISO 7388/1:1983 is developed
with reference to the German standard DIN 69871-1 A-type tool taper, so the external dimensions of these three standards are the same.
In China, its tool taper handle code for “JT”. Its characteristics are: flange thickness is small; there is a positioning notch for loading tools;
two end keyways are asymmetrically distributed.