Lid Stay Design Guide

Stays are a great way to support and control the support access doors and lids. In addition to supporting the lid, many stays come with benefit of damping and counterbalance. Damping ensures that the mechanism will close softly and safely. Counterbalace negates the weight of the lid allowing even heavy doors to be lifted with ease. There are two main considertions for choosing the appropriate stay: torque rating and door orientation.

Torque Rating

The torque rating varies with the weight and size of the door. Specifically, the torque rating is the weight of the door multiplied by the distance from its center of gravity to the hinge axis. For a uniform rectangular door this simplifies to the equation below:

Door Weight × (Door Depth ÷ 2) = Torque Rating

The door depth is the distance from the hinge to the free edge. The most common units for torque rating are inch-pounds (lbs•in), newton-meters (N•m), or kilogram force centimeter (kgf•cm). To ensure that you calculate the torque rating correctly, make sure that you are using units consistently. In other words, if you measure the depth of the door in inches and the weight in pounds, use inch-pounds for your torque rating. A conversion table for common units of torque is provided below:

Torque Units Converstion Table   (bold numbers are exact)
N•m kgf•cm lbs•in lbs•ft 
N•m 1 10.20 8.851 0.7376
kgf•cm 0.09807 1 0.8680 0.07233
lbs•in 0.1130 1.152 1 112
lbs•ft 1.356  13.83  12 1

To use the table, locate the row containing the current units on the left. Next, find the column of desired units at the top. Multiply current value by the the conversion factor at the intersection of the row and column. 

For example:
0.09807 N•m = 1 kgf•cm × 0.09807  13.83 kgf•cm = 1 lbs•ft × 13.83


Door Orientation

There are three common mounting configurations for stays illustrated below:

Lid Stay Orientation


 Stay Selection Guide

 Part NumberTorque Range per Pair
Downward SDS-100TV, SDS-C100TV
10.0 ~ 24.0 kg-cm
70 ~ 100 kg-cm
40 ~ 140 kg-cm, 20 ~ 40 kg-cm
140 ~ 300 kg-cm
Top-opening SDS-C301N
80 ~ 140 kg-cm
70 ~ 100 kg-cm 
140 ~ 300 kg-cm
40 ~ 140 kg-cm
Upward SDS-C301N
80 ~ 140 kg-cm
40 ~ 140 kg-cm
140 ~ 300 kg-cm
140 ~ 300 kg-cm
55 ~ 100 kg-cm (per piece)