I guess you could use the formula for that, then.

 

Joe, please refer to post #19.

 

I'll be crunching numbers as soon as I am done translating regulations and int'l correspondence on horse racing.

 

Doh.

Please refer to the timestamps on posts 19 and 20.

 

The Herb Adams book gets a regular workout around here-

Here are the pages that cover it.. If anybody wants hi-res pics of them just pm me your email address.

 

I'm pretty sure intelligence reports submitted on September 10, 2001 had timestamps on them, too, but that did not prevent the intended recipients from missing them.

 

 

Sprign rate is a function of diameter to the power of 4. A 1% error in thickness will give you a 4% error in spring rate. Paint will give you a 1% error.

 

20ft.lb on a 500ft.lb spring. It will at least put him in the ballpark. If they were decent springs they'd be labeled anyway.

 

And if the labels are missing along with the paint, well accuracy just went up.

 

The only material factors that affect the result from the mathematical calculation is the torsional modulus of the steel. All steels have near as makes no difference the same torsional modulus. Spring steel, high-strength low alloy steel, **** chinese steel, steel with a bunch of crap defects in it, etc. etc. etc. That is to say, if you use the number provided, it will be 95%+ correct, no matter what the springs are made of, as long as it's some sort of steel. I'm not sure what you mean by treatment failures (heat treatment? won't affect it).

As others have eluded to, the other factors you have mentioned will only lead to small errors in the calculation.

I would recommend doing both if you are deadset on making a spring compressor testing rig-a-ma-jig. Do the calculation on at least the first few springs you test to validate your test jig.

Have fun

 

It's easier to google online spring rate calculators to find your spring rate. However, you need an accurate caliper to put the correct info in.