How to Measure a Conical Spring
When measuring your conical spring, you must know the following dimensions:
- Small Outer Diameter
- Large Outer Diameter
- Free Length
- Wire Diameter
- Total Coils
- Solid Height
Please see graphic to the right for more help.
Conical springs are accurately measured with a dial caliper. The reason for this is because a caliper provides you with a more exact measurement. Wondering why this is so important? Well, take your spring's wire diameter as an example. In most cases, if the spring's wire diameter is off by 0.001" it'll affect your spring's rate and travel so one must have exact measurements when measuring a conical spring.
How to Measure Your Spring
Another thing you must focus on is your end types. The end types available are the following:
Closed and Square The ends are closed and don't have pitch, therefore, not all the coils on your spring will be active. In this case you may calculate your active coils by subtracting 2 coils from your spring's total coils: Total Coils - 2 = Active Coils.
Closed and Ground These ends are the same as closed and square ends but the ends go through a grinding process that grinds half a wire diameter off the first and last coils so that your spring will stand vertically. The calculation process for active coils is the same as the one used for closed and square ends : Total Coils - 2 = Active Coils.
Open Ends These ends are the opposite of closed and square ends because the ends don't close and don't have pitch. Therefore, all the coils of a spring with open ends are active.