Ace Designers Ltd. Is the manufacturer of Tool Changer Arm. Ace Designers Ltd. Is an ISO 9001:2000 certified company. The Tool Changer Arm is an important component of Arm Tool Changer assembly. The three models of arm are available to suit 3 basic sizes of tool taper shank; 30, 40 and 50. Each model of tool changer arm is available in different standard lengths. This makes it easy to choose standard model and length of arm to suit the requirement of ATC layout.