The additional spring kit can be used to further expand the parameters of the main HVT14D apparatus. As with the standard spring that comes with the main unit, each spring has a pair of adjustable spring holders. Again as with the standard spring setup the upper spring holder can be moved down the length of the spring and positioned on the long spring insert. This potentially allows for different effective lengths of each spring to tested (change in number of active coils).
Each spring end is held in place by 3 screws these are situated around the circumference of the spring holder. These need to be undone and removed to allow the spring to be pulled off of the holder. Each spring holder fixes into the top or bottom spring insert, the top spring insert has a long shaft with tapped hole spaced so that the position of the spring holder can be varied.
The spring holders are fixed onto the spring inserts by two socket head cap screws, these sit inside counter bored holes within the spring holders. The spring end must be removed in order for these fixings to be accessible.