local electrical code requirements dictate the size for the electrical service powering the machine machine power requirements are covered in the mill installation instructions and pre installation guide available online at haascnc.com these documents provide guidelines for the proper size cable for the particular machine configuration the airline must have an inner diameter of at least 1/2" or 13mm all the way from its source to the machine connecting the 1/2" hose directly to the hose barb with a hose clamp is preferred smaller fittings will significantly reduce the volume of air delivered and will hinder machine performance under demanding conditions with the appropriate power and air in place