If you have an existing spring or part of one, you will need to measure the outside diameter (width on the image below), the wire diameter and the number of coils in a 1cm length.
The overall length does not matter at the moment as I cut the springs to length for you.
TIP: To measure the coils/cm on a spring, place a ruler against one coil, then count (ignoring the first one) how many are in 1cm, if it if difficult to guess the number accurately (i.e. there are 3 and a bit) count the coils over a longer length (i.e. 5 cm) then divide bu the number of cm (i.e. 5).
TIP: To measure the wire diameter on a tension spring (or a compression spring that you can fully compress), count the number of coils in a length (fully compressed if it is a compression spring), then divide it by the length (i.e. count the coils in a 10mm length, then divide by 10)
Then look at the wire diameter column and see if I have one with the required size.
If not, go up (if you can not have a wider spring) or down (if you can not have a thinner spring), or either way if the diameter is not important.
Once you have found one or more, check the Coils/cm column to make sure the number of coils is near to the one you have.
The wire diameter and the number of coils are more important than the outside diameter, although the diameter does alter the strength as well.
At this point you may have seen one or more springs that may be suitable, but it is likely none match your spring entirely. If you have found more than 1 possibility I suggest you buy all of them, unless you need a long length, as my springs are very cheap, alternatively you could buy one which you will have the next working day and use that to decide if you need to go stronger or weaker from there.
If you have bought one and it is not the right strength, look on my list and note the strength value, then look for another that has a higher value (stronger) or smaller value (softer). I am afraid that unless you are a mathematician and want to calculate the ‘Rate’ you require and the rate of each of your selections, you will have to rely on a bit of trial and error.
I am not a mathematician, so please do not ask me to calculate it for you, but there is a calculator here if you require it (third Tab).
If you are still having trouble finding the correct spring, you may ring me on 01492535595