Ok, given your application, I'd suggest that you take the advice of
another poster and buy some spring stock from Brownell's. The one-off
flat-spring business is something that gunsmiths and their suppliers
are very good at. It probably is the easiest way for you to arrive at
I haven't looked at a Brownell's catalog for close to 20 years, but
for many things, they're the source. They know what they're selling.
Most spring steel is plain-carbon steel. You have two steps in heat
treatment: hardening and tempering.
To harden, you need to heat carbon steel to something like 1350 F to
1450 F. That's a medium cherry-red. You can get the idea by searching
Plain carbon steel has to be quenched very fast from the tamperature.
Mostly, that means water-quenching. But a thin spring is better
quenched in oil. It's less of a shock and less likely to damage the
steel, while still allowing full hardness, or something very close to
it. Motor oil is crappy for this but I doubt if you'll want to invest
in quenching oil. Do NOT use used oil. It will leave too many bubbles
on the surface of your spring and there will be soft spots under the
bubbles. It will be weaker.
Then you temper it.That relieves some of the stresses from hardening
and *slightly* softens the steel. But not much. It will make it much
more resilient. With plain-carbon steel, it's best if you do this
right away, after hardening.
I'll give you a temperature and time without explanation. It will give
you what you want. Heat your kitchen oven to 400 F, lay the spring on
a cookie sheet, and cook it for one hour.
That will produce a tougher and stronger spring than any of the
quickie methods. 400 F is a medium temperature for that kind of work.
You can go a little higher, probably, without hurting the performance
of your spring. Anything much lower, and it will be brittle. For
things like cutting blades, 350 F is usually preferred.
Good luck. Get GOOD quality spring steel, from Brownell's or similar.
Jim Stewart fired this volley in news:ktokfk$bps$1
To cut them to size and drill them, you may have to first anneal them,
then re-harden and re-temper.
If you have abrasive cutting methods, that won't be necessary.
You also can spot-anneal, which probably would be better.
Take a 10d nail and cut off the head. File the cut end reasonably
flat. Insert in a drill press, as if it was a drill bit, cut end down.
Clamp workpiece firmly. Bring the nail/bit down onto the work,
pressing firmly, until the spot under the cut-off nail head is deep
The spot will be annealed and can be drilled. This trick brought to
you by the gunsmiths who used to drill case-hardened '03 Springfield
receivers for scope mounts.
Ed Huntress fired this volley in
Ed, that only works for the holes. How about cutting the spring to size?
Abrasives (carefully applied so as not to draw the temper) would be the
For one like this, I'd use a Dremel or a die grinder with a cutoff
wheel, and work slowly so you don't draw the heat treatment.
Ha! I'm becoming so impatient that I don't read even one line ahead.
For a onesie or twosie, I try to avoid annealing the whole piece at
all costs. You're just not likely to do as well. Even heating to
transition temperature a second time, repeating what the manufacturer
did, is likely to coarsen the grain and make the part brittle.
I'm listening, just not understanding!
So you are saying I can't change the properties of a spring, that I must
find the same material as the original if I want the new spring to be
the same dimensions as the old one?
BQ340 fired this volley in news:52001941$0$19313
Almost correct: You can change the properties by hardening/tempering...
just not the spring force. It remains the same (nearly) for any given
alloy, regardless of the hardness
The primary property you change by altering the hardness is the yield
force, NOT the spring force.
You also can affect (positively) the durability of the spring by
increasing the yield point IF the deflection is such that it comes close
to the yield point when not hardened.
Someone recommended feeler gauges for stock. Also consider the rewind
springs in cheap tape measures (don't use an old, discarded one, as it
might already be severely fatigued).
BQ340 fired this volley in
AND tricky to adjust, probably.
But then, it's only a "music box" with a leaf contact in place of a reed.
Unless you're transmitting the code to a compatible receiver, the exact
speed doesn't matter very much.
Lloyd answered that clearly -- the spring rate will be almost exactly
the same, no matter what grade steel you use (except stainless) and no
matter how hard or soft it is.
What varies is the yield point (look it up) and, consequently, the
Maybe we can simplify this for you: How much, in inches or
millimeters, does that spring deflect at the ends, when it's in use?
Be patient; you'll get it. By now you know that you started with some
very common misconceptions. I've even known experienced machinists who
didn't believe it when it was explained to them. So you're not alone.
But we'll enlighten you. d8-)
I'm pretty sure the springs, in normal use, don't get very close to
the yield point. Based on this assumption most any steel hardened to a
spring temper will work. You do not need the same exact steel.
Differences in thickness will have a much greater affect on deflection
that differences in width. Twice as wide will be twice as stiff. Twice
as thick will be 8 times as stiff. So get some spring steel the same
thickness but a little wider and trim until it acts the way you want.
Someone here mentioned the use of feeler gauges. That's good advice.
And Ed mentioned using a nail to anneal spots for drilling. More good
advice. So buy a set of feeler gauges, trim to size with a Dremel tool
and grinding points and/or parting discs, anneal the three spots you
need, and trim the sides until it works the way you want.
Regular feeler gauges are not nearly as stiff as I need, but I see some
blue spring steel shim stock is available.
I will get some of that & from all the replies it sounds like that
should work but I may need to tweak the width to get the results I need.
BQ340 fired this volley in news:5200391a$0$49396
Again, I think you've missed the point. If the gauge is as thick, and as
wide as the spring you've got, then it will be exactly as "stiff".
That is, it will be if the remaining spring is steel, and not (say)
I understand what you are saying, I'm probably not using the proper
engineering terminology, but regular feeler gauges won't work.
Here is a video someone made of a different model but it has the same
springs & speed regulator assembly in action:
Regular feeler gauge stock would distort under the forces, the brass
weights are fairly heavy at the rpm's it operates at.
looks like what I will try.
I hope those links work!
BQ340 fired this volley in news:52004658$0$5579
I don't know what you mean by "regular feeler gauge stock". It comes in
all thicknesses, all the way up to "you can't bend it with your fingers",
and down to "feels like metal paper". Feeler gauges have many
thicknesses in one 'kit'.
The action of a fly-weight governor is controlled by two things. the
weight of the fly-weights and the strength of the springs. Altering
either alters the critical RPM.
So, you can make a couple of new springs and try them. If the speed
falls in the right area you say there is adjustment. If not then make
two more springs, either stronger of weaker as the case may be.
It's not rocket science and you can cut and drill most spring material
with common tools. It is a guess but I'd think that once you obtain
some spring stock, say a spring from a steel tape, and collected the
tools you could probably make 10 or 15 pairs in an hour, or maybe