Deadhead fisherman,
I began taking apart ink-pens and extracting the springs from within. They twist on very easy, and can be stretched out to different tensions. Check different pens for different sizes of springs as well.
I no longer use springs, instead I use a very ultra light, short rod that has a tip so thin its nearly invisible. The weight of my smallest jigs even weigh it down. I can detect fish inhailing, swim bys and the lightest of pick-ups. One secret is to watch the dainty coil of line that leaves the last eyehole on the rod. Prior to you rod tip or spring bobber quivering or moving, the line will tighten or loosen. Now that I fish with 1# and 3/4# test I find springless works better for me. Hard to watch the Hawks though if your paying attention to the rod tip and line! Good luck.