Convert torsion spring mini mills to air spring.

Newer mini mills use a torsion spring mounted on the side of the column to support the head. This kit provides all the parts required to change to a vertical air spring that mounts inside and above the column.

With the air spring installed, you can move the mill head up until the top of the casting is almost flush with the top of the column. You can move it down until it almost contacts the adjustable Z-axis stop set in its lowest position.

Besides all the parts required to mount the air spring, this kit also includes a longer Z-axis rack so you can take advantage of the longer head motion.

This air spring has about 35 pounds of force. This is not enough to totally support the head, but it is a heck of a lot more support than the torsion arm provides.