Ah, hmm, we'll try this one more time.

Back in the old days (not that old, I'm talking about the sixties), we would put an acetylene torch to the springs until they drooped to what we were looking for. Not very scientific, and not guaranteed to drop the car uniformly, but I did manage to have some nice looking 544's with moon hub-cabs looking pretty sharp. Of course the Mopar, Chevy, and Ford guys never "got it", but that obviously didn't matter to me much! Besides, my 42 Caddy trumped all that!

The bottom coil. And the bottom line is that cutting spring coils is a hack job, a jerry-rig, a ghetto-fix, some Okie engineering, etc. etc.
If you want to lower the car, buy lowering springs.

Why do you want to lower it? It may throw your camber off and possibly the caster too. Not to mention putting the shock in a partially compressed position and reducing their ability to damp on the first stroke.

Do yourself a favor and look into it before doing it, please.

Happy Bricking

Interesting, you are thinking of that.

My opinion is that it is not like a ball point pen spring that you just go whacking on.

I would think the ends of the coils are made to create a more flat bottom.

I imagine in the last half turn of a coil, on each end, the angle straightens more of a right angle to the spring’s axis, therefore giving more length of the diameter of the coil to being trimmed for a base stance. Keeping coils square to the axis is crucial other wise they will bow instead of collapse evenly.

Cutting anything will upset the springs working rate of the steels internal tensions through out the height and overall that means things will not be linear when compare to a like spring cut exactly the same way. Springs have tolerances and are pair in sets during final inspection by lots. No true calculation is possible that I know of. Testing is quite extensive. No pun intended, I think? Maybe intensive would be better?

If you are just messing around and have an extra spare set, it might prove to be a good experiment. Or this could be another way to scrap springs besides tossing them into the same pile at the junkyard.

Phil