> You might get lucky and find a ballpoint pen spring that fits, but I've made
> coil springs for 3-jaw chucks by winding guitar string around an appropriately
> (under)sized drill bit, held in a vise. It's worth trying!

Making a spring is easy, and finding a commercially made spring to fit is often
not a big deal.


Spring wire (music wire) is available at pretty much any hobby store, as well as
on line, and smaller gauges are available at music stores. Note that many modern
guitar strings are not suitable for use as spring material. Piano string pretty
much is (AFAIK). Easy to wind, even by hand, over a mandrel. For compression
springs, try a mandrel about 10 to 15% smaller than the nominal ID of the
spring, and spacing can be done using another piece of wire (same or larger
size, as needed). Before I had a lathe, I wound a lot of springs using nothing
but a rod, some wood to grip with, and a vise.


Not a metallurgist, but experience and training tell me that springs fail, often
without warning, due to flaws that are not visible even under a microscope. I
have seen, in large springs, flaws using mag particle and dye penetrant testing,
that lead to failure not long after the tests (sometimes people don't listen
when told that failure is immanent). Small springs can't really even be tested
using these techniques, and a small flaw from rust or wear or impact or.....
They fail. If the cleaning using reasonable technique causes a failure to a
spring, to a saw plate, to anything, it was likely going to fail anyway.

Of course, reasonable technique is key, as noted:


>I was cleaning a saw set and left it in the vinegar overnight. The frame of the
>set was nicely cleaned along with the adjustment screw, but when I went to put
>the thumb nut back on the screw it rattled.

I have never had this issue (I swear. Really. No, I mean it. Am I convincing
you???) but if you do, you learn quickly. To the spring, if there is a crack
starting, or a deep pit under the rust, or a spot where the rust is just right,
the acid clean will lead to a crack. Abrasive cleaning MIGHT not, as it will
take the stress riser out by removing the material around it, rather than
accentuating it by cutting into it. (A major issue when I wear my boiler
inspection and repair hat)