Spring Tester

[Max.Brass]

I have a number of springs, some left from other projects and some acquired with my Reynard 84F, many of which I cannot read the Spring Rate that was once scratched on one end.

Does anyone have any thoughts for an improvised, inexpensive but reasonably accurate spring tester?

Has anyone built there own tester? I assume a load cell can be purchased reasonable cheaply and dial indicator and shop press utilized to make something functional.

I'd like to have a digital readout rather the hydraulic pressure - this might just be my lack of familiarity with the hydraulics.

Thanks,

Max

[Hawke]

I have a very accurate CTW shock dyno that can measure spring rates to a 1/10th of a pound/inch. Not much help to you though, but some of the on line spring rate calculators are surprisingly accurate. I’ve found them to be good to be within a couple of pounds. Of course, measurement accuracy is the key.

This one works OK https://eibach.com/spring-rate-calcu...I5gIhFEu8IboNH

[Craig Henry]

Max,

Very simple to calculate the rate. Find an online compression spring calculator, measure what you have, input the values and you will have your rate. It's been decades since I verified a bunch of springs I had but all my calculation came out within a couple of pounds of what was marked on known new springs.

If I recall correctly, the wire diameter and number of coils are the sensitive inputs. Also, I think most of our springs are evenly ground flat at the top and bottoms resulting in a whole number for the number of coils? I would research spring steel material properties to verify the online calculator you find is using good default values.

Edit: I see Grahame's link is Eibach's calculator...

Good luck,

Craig