Posted December 11th, 2015 at 9:58 am by Dan Musick
Most residential, commercial and industrial sectional garage doors use standard lift tracking and standard torsion hardware.
The door rises vertically a short distance and then moves horizontally in the tracks.
These doors use flat cable drums.
On standard lift doors the formula is (DH/DC)+1, or the door height in inches divided by the drum circumference in inches, plus one. After winding the spring you may need to add or subtract a quarter turn or more.
Vertical lift doors are normally found in commercial and industrial applications, such as on loading docks. These doors rise vertically the entire travel of the door.
The cable drums for these are fully tapered.
The formula for determining the number of turns on these springs is based on door height and drum number.
High lift doors rise vertically – some times a distance as short as a foot or more, sometimes more than half the door height – and then the door rides in the horizontal tracks. When the door is fully open, the lower part of the door hangs vertically in the vertical track extension.
High lift drums are partially tapered and partially flat.
The formulas for determining the number of turns to wind the springs is based on the drum number, door height and high lift dimension, which is the distance from the top of the door to the center of the horizontal track.
As with the vertical lift doors, the formula for the number of turns on the springs is complex. Here, we rely on software or drum charts to calculate the number of turns to wind the springs. If you contact us we can help you with this.