I need to wind a couple of large-diameter, fine wire springs. (light
force, balancing device. And I cannot find any "stock" springs that fit
the bill)

I have good luck with wire that is larger, and whose elastic limit is
mightily overcome by the radius of the arbor. Then they relax only a
little, and come off the arbor a few percent larger than they were wound.
I have OK luck with very small diameter springs of fine wire.

But with 0.013" music wire, I'm having trouble getting the right arbor
size for a large-diameter spring. At anything near the desired size, the
wire is only slightly bent by the process; so I know I'll need a MUCH
smaller arbor -- but how small?

I need a spring es-aKly 5/8" o.d., 1-7/8" long, of twelve turns of
0.013" phosphated steel music wire.

Anyone have a rule-of-thumb for sizing the arbor for fine wire sizes?

Or, am I stuck trying 15-20 different diameters until something just
works?

LLoyd

On 07/22/2010 09:57 AM, Lloyd E. Sponenburgh wrote:
I need to wind a couple of large-diameter, fine wire springs. (light
force, balancing device. And I cannot find any "stock" springs that fit
the bill)

I have good luck with wire that is larger, and whose elastic limit is
mightily overcome by the radius of the arbor. Then they relax only a
little, and come off the arbor a few percent larger than they were wound.
I have OK luck with very small diameter springs of fine wire.

But with 0.013" music wire, I'm having trouble getting the right arbor
size for a large-diameter spring. At anything near the desired size, the
wire is only slightly bent by the process; so I know I'll need a MUCH
smaller arbor -- but how small?

I need a spring es-aKly 5/8" o.d., 1-7/8" long, of twelve turns of
0.013" phosphated steel music wire.

Anyone have a rule-of-thumb for sizing the arbor for fine wire sizes?

Or, am I stuck trying 15-20 different diameters until something just
works?

As a suggestion, try an arbor that's close to the desired diameter of
the spring, and stretch the hell out of the wire as you wind it onto the
arbor.

I have ABSOLUTELY NO CLUE if this will work for you, but I know that
taking a bent-up, ugly, twisted piece of wire and stretching it straight
does a dandy job, presumably because I've exceeded the elastic limit
everywhere that it's bent. So I'm trying to think how you can get the
same effect for a wire for which you want a controlled bend.

Alternately, make a split arbor, lubricate the hell out of it, hold both
ends of the wire tight on the arbor, then expand the arbor until the
wire stretches a bit. The more splits in the arbor the prettier the
spring will be -- but what's the matter with a square spring if it works?

Again, the idea is to put the wire in the position you want, then
stretch it past its elastic limit in position.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html

Tim Wescott fired this volley in
:

As a suggestion, try an arbor that's close to the desired diameter of
the spring, and stretch the hell out of the wire as you wind it onto the
arbor.

Did. Didn't change a thing. It didn't even make the resultant
"spaghetti" any smaller than if I had not.

I think the expanding arbor thing might be more trouble than buying or
making a whole range of arbor sizes until I find one that works G.

LLoyd

"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message
.70...
Tim Wescott fired this volley in
:

As a suggestion, try an arbor that's close to the desired diameter of
the spring, and stretch the hell out of the wire as you wind it onto the
arbor.

Did. Didn't change a thing. It didn't even make the resultant
"spaghetti" any smaller than if I had not.

I think the expanding arbor thing might be more trouble than buying or
making a whole range of arbor sizes until I find one that works G.

LLoyd

The old-fashioned spring-winding accessories for lathes, dating back to the
'20s, put a *lot* of tension on the wire, as Tim says. I don't know how
much, or whether it will work in your case, but you might try increasing
tension until it breaks, and then back off.

The yield strength of fine, hard-drawn carbon-steel wire is pretty amazing.
Small diameters of music wire approach 300,000 psi.

--
Ed Huntress

"Ed Huntress" wrote:

The yield strength of fine, hard-drawn carbon-steel wire is pretty amazing.
Small diameters of music wire approach 300,000 psi.

That number is scary if you get wrapped up in your wire. I made some .078 dia springs for
a line at work. Tight wound, 9/16" dia. I carefully cut each length of wire, made damn
sure it couldn't grab me and ran the lathe on slowest rpm.

I'll never work off a spool. It is way too dangeous.

Wes
--
"Additionally as a security officer, I carry a gun to protect
government officials but my life isn't worth protecting at home
in their eyes." Dick Anthony Heller

"Wes" wrote in message
...
"Ed Huntress" wrote:

The yield strength of fine, hard-drawn carbon-steel wire is pretty
amazing.
Small diameters of music wire approach 300,000 psi.

That number is scary if you get wrapped up in your wire. I made some .078
dia springs for
a line at work. Tight wound, 9/16" dia. I carefully cut each length of
wire, made damn
sure it couldn't grab me and ran the lathe on slowest rpm.

I'll never work off a spool. It is way too dangeous.

Wes

The neat way to cut that wire is to nick it with a cutoff wheel (on a
Dremel, if you have one handy) and then bend to break it.

50-pound steel fishing leader is the same deal. Really nasty. I keep a pair
of extra-hard dykes handy for that when I'm fishing, but I use the nick
method when I'm making leaders at home.

--
Ed Huntress

On 07/22/2010 10:52 AM, Lloyd E. Sponenburgh wrote:
Tim fired this volley in
:

As a suggestion, try an arbor that's close to the desired diameter of
the spring, and stretch the hell out of the wire as you wind it onto the
arbor.

Did. Didn't change a thing. It didn't even make the resultant
"spaghetti" any smaller than if I had not.

I think the expanding arbor thing might be more trouble than buying or
making a whole range of arbor sizes until I find one that worksG.

I suspect that with such a light bend your whole process would be very
susceptible to variations in wire size and hardness, and possibly even
the mood of the operator and the phase of the moon. If you're making
more than a few springs it may be more accurate to say "obtaining a
whole range of arbor sizes and constantly fiddling with which one to use
on a particular day".

I _think_ that my expanding arbor idea would be much more repeatable, if
tedious to make the first time.

Alternately, if you're starting with a straight or not too bent wire,
you could make the spring with a series of small bends, i.e. octagonal,
hexa-deca-agonal, etc. It'll be ugly, but it would work.

Come to think of it, if you have a mill and an index table, you could
make a many-sided arbor and get a spring of many small bends that's nice
and regular, instead of some hand-bent horror.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html

On Thu, 22 Jul 2010 12:52:03 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Tim Wescott fired this volley in
:

As a suggestion, try an arbor that's close to the desired diameter of
the spring, and stretch the hell out of the wire as you wind it onto the
arbor.

Did. Didn't change a thing. It didn't even make the resultant
"spaghetti" any smaller than if I had not.

I think the expanding arbor thing might be more trouble than buying or
making a whole range of arbor sizes until I find one that works G.

I've designed and prototyped quite a bit of coil winding tooling for
odd lamp filaments that are made spring winding machines. (These are
low volume, expensive, typically high-watt lamps for medical
applications and studio lighting, etc.) If there's a tight spec on the
coil diameter, it's almost always necessary to pick the final mandrel
size by trial and error, and the company doing this has been at it for
about 80 years. But it doesn't usually take more than 1 or 2 tweaks,
and I don't imagine it will in your case either as long as the wire is
consistent.

BTW, the machines (Sleeper & Hartley winders) have some provision for
back tension on the wire, but can't apply an awful lot. More important
is keeping the wire guide bushing close to the mandrel while winding.

--
Ned Simmons

On Thu, 22 Jul 2010 12:52:03 -0500, Lloyd E. Sponenburgh wrote:

Tim Wescott fired this volley in
:

As a suggestion, try an arbor that's close to the desired diameter of
the spring, and stretch the hell out of the wire as you wind it onto
the arbor.

Did. Didn't change a thing. It didn't even make the resultant
"spaghetti" any smaller than if I had not.

I think the expanding arbor thing might be more trouble than buying or
making a whole range of arbor sizes until I find one that works G.

What kind of diameters are we talking about? Could you do some test bends
around, say, drill bits?

Good Luck!
Rich

"Rich Grise" wrote in message
news
On Thu, 22 Jul 2010 12:52:03 -0500, Lloyd E. Sponenburgh wrote:

Tim Wescott fired this volley in
:

As a suggestion, try an arbor that's close to the desired diameter of
the spring, and stretch the hell out of the wire as you wind it onto
the arbor.

Did. Didn't change a thing. It didn't even make the resultant
"spaghetti" any smaller than if I had not.

I think the expanding arbor thing might be more trouble than buying or
making a whole range of arbor sizes until I find one that works G.

What kind of diameters are we talking about? Could you do some test bends
around, say, drill bits?

Good Luck!
Rich


you know, don't you, that the 'real' spring winding machines extrude the
wire against an angled anvil that is tilted in X,Y (presuming the wire is
fed in Z) so that it causes the wire to bend to the desired spiral - if you
build that, then it's simple enough to adjust to get the diameter and
spacing you want, no adjustable mandrils required

"Bill Noble" wrote:

you know, don't you, that the 'real' spring winding machines extrude the
wire against an angled anvil that is tilted in X,Y (presuming the wire is
fed in Z) so that it causes the wire to bend to the desired spiral - if you
build that, then it's simple enough to adjust to get the diameter and
spacing you want, no adjustable mandrils required

The first time uncle explained a spring winder it took me a while to realize he was
describing what you wrote above.

Wes
--
"Additionally as a security officer, I carry a gun to protect
government officials but my life isn't worth protecting at home
in their eyes." Dick Anthony Heller

"Bill Noble" fired this volley in
:

you know, don't you, that the 'real' spring winding machines extrude
the wire against an angled anvil that is tilted in X,Y (presuming the
wire is fed in Z) so that it causes the wire to bend to the desired
spiral - if you build that, then it's simple enough to adjust to get
the diameter and spacing you want, no adjustable mandrils required

Yep; well, _fed_, not extruded, in most cases. I get to see one in
animation every time an episode of "How it's Made" comes on.

But Bill, I need two springs. I have a spring winder.

And FWIW, I've already made them successfully.

LLoyd

On Jul 23, 11:32*pm, "Bill Noble" wrote:
...
you know, don't you, that the 'real' spring winding machines extrude the
wire against an angled anvil that is tilted in X,Y (presuming the wire is
fed in Z) so that it causes the wire to bend to the desired spiral - if you
build that, then it's simple enough to adjust to get the diameter and
spacing you want, no adjustable mandrils required.

I wonder if an equivalent could be made from a scissors knurl with
grooved rollers. Tilt the near end down to grab the wire between the
lower roller and the shaft in the spindle, and adjust the upper roller
or the crossfeed screw to change the wire loop diameter.

There is an adjustable fine wire feeder in your MIG welder.

jsw

On Fri, 23 Jul 2010 20:32:59 -0700, "Bill Noble"
wrote:


you know, don't you, that the 'real' spring winding machines extrude the
wire against an angled anvil that is tilted in X,Y (presuming the wire is
fed in Z) so that it causes the wire to bend to the desired spiral - if you
build that, then it's simple enough to adjust to get the diameter and
spacing you want, no adjustable mandrils required

That's true for inexpensive springs with loose tolerances. Precision
springs are still wound on mandrels. Look in McMaster to see the
difference in tolerance and price between standard and precision
springs.

--
Ned Simmons

On Jul 22, 12:57*pm, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:




Or, am I stuck trying 15-20 different diameters until something just
works?

LLoyd

I have no rule of thumb, but you ought to be able to get the right
arbor size using a binary search or whatever you want to call it.
Same idea as bracketing when shooting. You know 5/8 dia is going to
be too big. So try something like 3/8 dia. If that is too small then
try 1/2 inch dia. Assuming that is too big, then estimate the correct
size based on one being too big and the other too small.

I would think having the same tension on the wire would be important.
I would wrap the turns too close together and then stretch the sping
to the right length.

Dan

" fired this volley in news:3a3c1700-
:

I would think having the same tension on the wire would be important.
I would wrap the turns too close together and then stretch the sping
to the right length.


Yes and yes. I have an adjustable tensioner, and can break the wire with
it, if I clamp down too tightly.

The wire I have is _almost_ straight -- 0.013" wire on a 5" diameter
spool.

The long, hard way for me would be to wrap it on the correct arbor, then,
on the arbor, anneal, heat treat to harden, then temper and strain-
relieve. Then it would come out spot-on every time. This might even be
the way large diameter light-force springs are made (??).

But I only have two springs to make now, and probably one or two every
few years after that (at least for this machine). And I don't have a
heat treating oven.

I think I will just try a binary search on the right size arbor. The
tension, I can keep constant; even measure.

I'm betting the arbor size will be _really_ critical, because I'm going
to be counting on a certain (large) amount of recovery of the coil to get
it back to its nominal size.

LLoyd

"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message
. 3.70...
" fired this volley in news:3a3c1700-
:

I would think having the same tension on the wire would be important.
I would wrap the turns too close together and then stretch the sping
to the right length.


Yes and yes. I have an adjustable tensioner, and can break the wire with
it, if I clamp down too tightly.

The wire I have is _almost_ straight -- 0.013" wire on a 5" diameter
spool.

The long, hard way for me would be to wrap it on the correct arbor, then,
on the arbor, anneal, heat treat to harden, then temper and strain-
relieve. Then it would come out spot-on every time. This might even be
the way large diameter light-force springs are made (??).

But I only have two springs to make now, and probably one or two every
few years after that (at least for this machine). And I don't have a
heat treating oven.

I think I will just try a binary search on the right size arbor. The
tension, I can keep constant; even measure.

I'm betting the arbor size will be _really_ critical, because I'm going
to be counting on a certain (large) amount of recovery of the coil to get
it back to its nominal size.

LLoyd

If your wire is music wire or something similar (straight-carbon, at around
0.9% - 1.2%C), you will never recover the combination of strength and
ductility it has now through heat treatment. No kind of heat treatment. Most
of the wire's strength is the result of draw-hardening (work hardening) and
that strengthening mechanism produces different results from
phase-conversion through heat treatment.

--
Ed Huntress

"Ed Huntress" wrote:

If your wire is music wire or something similar (straight-carbon, at around
0.9% - 1.2%C), you will never recover the combination of strength and
ductility it has now through heat treatment. No kind of heat treatment. Most
of the wire's strength is the result of draw-hardening (work hardening) and
that strengthening mechanism produces different results from
phase-conversion through heat treatment.

When I make springs, either carbon or stainless, I set the springs in my oven. I was
looking for the temperatures when I ran into this.

http://www.rockfordspring.com/relaxationofsprings.asp

Not what I was looking for, sounds like it is geared to making sure a spring keeps its
characteristics.

http://home.earthlink.net/~bazillion/finish.html#stress Is more what I was looking for.

Whenever I make springs, I ask uncle for the stress relieving temps since I never can
remember them. Uncle ran coil winders for a number of years before trying selling
Orchids.

Wes

--
"Additionally as a security officer, I carry a gun to protect
government officials but my life isn't worth protecting at home
in their eyes." Dick Anthony Heller

Wes fired this volley in news:8u32o.363826
:

http://www.rockfordspring.com/relaxationofsprings.asp

I'm not too worried about relaxation. These springs will not be under load
except while actually being used.

On Thu, 22 Jul 2010 13:32:31 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

" fired this volley in news:3a3c1700-
:

I would think having the same tension on the wire would be important.
I would wrap the turns too close together and then stretch the sping
to the right length.


Yes and yes. I have an adjustable tensioner, and can break the wire with
it, if I clamp down too tightly.

The wire I have is _almost_ straight -- 0.013" wire on a 5" diameter
spool.

The long, hard way for me would be to wrap it on the correct arbor, then,
on the arbor, anneal, heat treat to harden, then temper and strain-
relieve. Then it would come out spot-on every time. This might even be
the way large diameter light-force springs are made (??).

But I only have two springs to make now, and probably one or two every
few years after that (at least for this machine). And I don't have a
heat treating oven.

I think I will just try a binary search on the right size arbor. The
tension, I can keep constant; even measure.

I'm betting the arbor size will be _really_ critical, because I'm going
to be counting on a certain (large) amount of recovery of the coil to get
it back to its nominal size.

LLoyd


Could you turn an arbitrary shallow taper, wind a spring, mark the
spring before releasing it (maybe a paint strip to tell you where each
turn ends up) and then find the mandrel size directly?

On Thu, 22 Jul 2010 11:18:43 -0700, wrote:
On Jul 22, 12:57Â*pm, "Lloyd E. Sponenburgh" wrote:
I need to wind a couple of large-diameter, fine wire springs [...] I'm
having trouble getting the right arbor size for a large-diameter spring
[...] 5/8" o.d., 1-7/8" long, of twelve turns of 0.013" phosphated
steel music wire. Anyone have a rule-of-thumb for sizing the arbor for
fine wire sizes? Or, am I stuck trying 15-20 different diameters until
something just works?

I have no rule of thumb, but you ought to be able to get the right arbor
size using a binary search or whatever you want to call it. Same idea
as bracketing when shooting. You know 5/8 dia is going to be too big.
So try something like 3/8 dia. If that is too small then try 1/2 inch
dia. Assuming that is too big, then estimate the correct size based on
one being too big and the other too small.

I would think having the same tension on the wire would be important. I
would wrap the turns too close together and then stretch the sping to
the right length.

I realize you (LS) have already made the springs but am posting anyway
about a possible method. AFAICT, springback in degrees for springs like
you are bending will be about e = a*d*k, where a = total angle bent;
d = diameter of bend, at wire midline; e = springback angle; and
k = arbitrary constant that wraps up materials properties (yield strength,
Young's modulus), units (mm, degrees, etc), and wire thickness (which has
an inverse effect on k).

To determine k, wind a test spring on a test mandrel, measure springback,
and compute it. For example, if A" = 1800 degrees = 5 turns and mandrel
diameter is 0.5 (so D' = 0.5+0.013) and springback is e=360 degrees,
compute k = e/(A"*D") = 360/(1800*0.513) = 0.390.

In following, let A = target angle and D = target diameter (0.625-0.013 =
0.612"). Let A', D' be the winding angle and diameter that springs back
to the target angle and diameter, via A = A'-e' = A' - k*A'*D' equation.

Springback doesn't change wire length, so A*D = A'*D' or A' = A*D/D'.
Thus A = A*D/D' - k*A*D*D'/D' or 1 = D/D' - k*D, whence D' = D/(1+k*D).
Using the made-up example numbers gives D' = 0.612/(1+.239) = 0.49

Although the e = a*d*k model that I mentioned above doesn't show any
"knee in overcoming the elastic limit" behavior as you talked about in a
later post (at 2010.07.22 23:22:57), it still would be interesting to
apply the D' = D/(1+k*D) equation to your springs and check its accuracy.

--
jiw

James Waldby fired this volley in news:i2f376$p9c$1
@news.eternal-september.org:

I realize you (LS) have already made the springs but am posting anyway
about a possible method.

All good info. Thanks. I'm compiling a mini "library" of spring-winding
stuff.

As time permits, I will challenge the math you've presented. It looks
rational and reasonable.

I'm still confused about the "knee", though, because it's _really_ there.
Perhaps it's explained by the math...

LLoyd

On Sat, 24 Jul 2010 18:51:00 -0500, Lloyd E. Sponenburgh wrote:
On Sat, 24 Jul 2010 16:09:10, James Waldby [wrote]:
I realize you (LS) have already made the springs but am posting anyway
about a possible method.

All good info. Thanks. I'm compiling a mini "library" of
spring-winding stuff.

As time permits, I will challenge the math you've presented. It looks
rational and reasonable.

I'm still confused about the "knee", though, because it's _really_
there. Perhaps it's explained by the math...

The thing to challenge is the model, e = k*A*D (e=springback angle,
A=total angle wound, D=diameter wound, k=material and units constant)
which is linear in A and D. That agrees with some of the online
references I looked at, but not all. If I could have read the
exponents in the four equations just before halfway thru
http://www.thefabricator.com/article/tc/roll-forming-high-strength-materials
I would have tried to use a non-linear model.

--
jiw

James Waldby wrote:

... If I could have read the
exponents in the four equations ...

I'm pretty sure it's a "3". Here's the best that I could do, but it was
only a 3kB image:
http://home.comcast.net/~bobengelhardt/formula1.jpg

Bob

On Sat, 24 Jul 2010 18:51:00 -0500
"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote:

snip
All good info. Thanks. I'm compiling a mini "library" of
spring-winding stuff.

There is a book in the Workshop Practice series, "Spring Design and
Manufacture" by Tubal Cain. It does have at least one chapter on
winding springs. I gave it a cursory glance, some of the same problems
discussed here were covered. See:

http://www.amazon.com/Spring-Design-...dp/0852429258/

There was a crappy pdf version at www.freebookspot.com a while back. It
is readable, may give you some ideas (shrug).

--
Leon Fisk
Grand Rapids MI/Zone 5b
Remove no.spam for email

Leon Fisk fired this volley in
:

http://www.amazon.com/Spring-Design-...Practice/dp/08
52429258/

Oh, MAN! That's a good one! I got it off the freebookspot site.

THANKS!

LLoyd

Lloyd E. Sponenburgh wrote:
I need to wind a couple of large-diameter, fine wire springs. (light
force, balancing device. And I cannot find any "stock" springs that fit
the bill)

I have good luck with wire that is larger, and whose elastic limit is
mightily overcome by the radius of the arbor. Then they relax only a
little, and come off the arbor a few percent larger than they were wound.
I have OK luck with very small diameter springs of fine wire.

But with 0.013" music wire, I'm having trouble getting the right arbor
size for a large-diameter spring. At anything near the desired size, the
wire is only slightly bent by the process; so I know I'll need a MUCH
smaller arbor -- but how small?

I need a spring es-aKly 5/8" o.d., 1-7/8" long, of twelve turns of
0.013" phosphated steel music wire.

Anyone have a rule-of-thumb for sizing the arbor for fine wire sizes?

Or, am I stuck trying 15-20 different diameters until something just
works?

LLoyd

Might find some info here.
I believe he has a formula to determine the arbor size you need.

http://home.earthlink.net/~bazillion/intro.html

--
Steve W.

"Steve W." fired this volley in news:i2a70m$9d2$1
@speranza.aioe.org:

Might find some info here.
I believe he has a formula to determine the arbor size you need.

That was the first search I hit, too.

There's no formula, just "pick an arbor just a little smaller than the
desired size of the spring."

It's also a very non-technical approach to the subject, with a lot of
"this'n'that will vary, but there's no way to know how..." stuff.

I was kind of hoping someone had a table with different wire metals and
rules, plus maybe a nomograph plotting diameter vs. wiresize vs. abor
size.

(Hopin' too much, huh?)

LLoyd

"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message
. 3.70...
"Steve W." fired this volley in news:i2a70m$9d2$1
@speranza.aioe.org:

Might find some info here.
I believe he has a formula to determine the arbor size you need.

That was the first search I hit, too.

There's no formula, just "pick an arbor just a little smaller than the
desired size of the spring."

It's also a very non-technical approach to the subject, with a lot of
"this'n'that will vary, but there's no way to know how..." stuff.

I was kind of hoping someone had a table with different wire metals and
rules, plus maybe a nomograph plotting diameter vs. wiresize vs. abor
size.

(Hopin' too much, huh?)

LLoyd

I have an entire book (a little old MAP book, or similar) on spring-winding
and other non-cutting jobs on small lathes. It's in a box, in my storage
area, three miles away. Otherwise I'd pull it out for you. g

But I'd be skeptical of any specific formula. You might get a ball-park
number out of it. But there's nothing you won't learn by wrapping the wire,
hard, around a few test "arbors," like pieces of pipe or bar stock.

--
Ed Huntress

"Lloyd E. Sponenburgh" lloydspinsidemindspring.com fired this volley in
. 3.70:

just "pick an arbor just a little smaller than the
desired size of the spring."


Well, I learned a lot in an hour of shop time.

I ended up using drills as arbors, as someone suggested here.

The first thing I discovered is that the underside of the wire guide must
not "back bend" the wire -- at all, if the wire is straight to begin
with. This wire was so close to straight as not to be an issue -- it
comes off the roll with a bend radius of about 40".

The second thing I discovered confirmed my impression that the knee in
the "overcoming the elastic limit" curve would be sharp. It was almost a
right angle G.

I started with a 3/8" arbor tonight. I got a spring about 1-1/4" in
diameter.

I did it with a 5/16" arbor, and got a 3/4" spring.

I did it with a 1/4" arbor, and got a 5/16" spring ---BOING! Hit the
knee.

Tension wasn't as much of an issue as everyone including me suspected.
Everything from "nearly breaking" to "just keeping it straight over the
arbor" turned out stuff varying only about 25% in diameter. So it's an
issue, but not a big one. Consistent tension is the magic number.

I fiddled with 9/32" and tension, and got two springs made (extension
wound) that would fit, then drew them out to the correct length to form
compression springs.

They work fine as-is. A 1-hour soak at 430F should take the strains out,
to make them stay in the shape they're in now.

LLoyd

"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message
. 3.70...
"Lloyd E. Sponenburgh" lloydspinsidemindspring.com fired this volley in
. 3.70:

just "pick an arbor just a little smaller than the
desired size of the spring."


Well, I learned a lot in an hour of shop time.

I ended up using drills as arbors, as someone suggested here.

The first thing I discovered is that the underside of the wire guide must
not "back bend" the wire -- at all, if the wire is straight to begin
with. This wire was so close to straight as not to be an issue -- it
comes off the roll with a bend radius of about 40".

The second thing I discovered confirmed my impression that the knee in
the "overcoming the elastic limit" curve would be sharp. It was almost a
right angle G.

I started with a 3/8" arbor tonight. I got a spring about 1-1/4" in
diameter.

I did it with a 5/16" arbor, and got a 3/4" spring.

I did it with a 1/4" arbor, and got a 5/16" spring ---BOING! Hit the
knee.

Tension wasn't as much of an issue as everyone including me suspected.
Everything from "nearly breaking" to "just keeping it straight over the
arbor" turned out stuff varying only about 25% in diameter. So it's an
issue, but not a big one. Consistent tension is the magic number.

I fiddled with 9/32" and tension, and got two springs made (extension
wound) that would fit, then drew them out to the correct length to form
compression springs.

They work fine as-is. A 1-hour soak at 430F should take the strains out,
to make them stay in the shape they're in now.

LLoyd

Another RCM success story...now we can move on to solving the Gulf oil
spill..... g

--
Ed Huntress

Ed Huntress wrote:
"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message
. 3.70...
"Lloyd E. Sponenburgh" lloydspinsidemindspring.com fired this volley in
. 3.70:

just "pick an arbor just a little smaller than the
desired size of the spring."

Well, I learned a lot in an hour of shop time.

I ended up using drills as arbors, as someone suggested here.

The first thing I discovered is that the underside of the wire guide must
not "back bend" the wire -- at all, if the wire is straight to begin
with. This wire was so close to straight as not to be an issue -- it
comes off the roll with a bend radius of about 40".

The second thing I discovered confirmed my impression that the knee in
the "overcoming the elastic limit" curve would be sharp. It was almost a
right angle G.

I started with a 3/8" arbor tonight. I got a spring about 1-1/4" in
diameter.

I did it with a 5/16" arbor, and got a 3/4" spring.

I did it with a 1/4" arbor, and got a 5/16" spring ---BOING! Hit the
knee.

Tension wasn't as much of an issue as everyone including me suspected.
Everything from "nearly breaking" to "just keeping it straight over the
arbor" turned out stuff varying only about 25% in diameter. So it's an
issue, but not a big one. Consistent tension is the magic number.

I fiddled with 9/32" and tension, and got two springs made (extension
wound) that would fit, then drew them out to the correct length to form
compression springs.

They work fine as-is. A 1-hour soak at 430F should take the strains out,
to make them stay in the shape they're in now.

LLoyd

Another RCM success story...now we can move on to solving the Gulf oil
spill..... g



You are out of fate, Ed.
That sucker, er.. gusher, is capped.

And a tropical storm is heading that way to "test" it!


--

Richard Lamb

Lloyd E. Sponenburgh wrote:

I was kind of hoping someone had a table with different wire metals
and rules, plus maybe a nomograph plotting diameter vs. wiresize vs.
abor size.

ISTR Machinery's Handbook having a section on that, but it's been awhile
since I browsed through a copy.

Jon

I was kind of hoping someone had a table with different wire metals and
rules, plus maybe a nomograph plotting diameter vs. wiresize vs. abor
size.

(Hopin' too much, huh?)

LLoyd


There was an article published in the Home Shop Machinist many years
ago with nomograms. I saw it on the web awhile ago. Email me. I
think I saved it somewhere.

RWL

On 2010-07-22, Lloyd E. Sponenburgh lloydspinsidemindspring.com wrote:
I need to wind a couple of large-diameter, fine wire springs. (light
force, balancing device. And I cannot find any "stock" springs that fit
the bill)

I have good luck with wire that is larger, and whose elastic limit is
mightily overcome by the radius of the arbor. Then they relax only a
little, and come off the arbor a few percent larger than they were wound.
I have OK luck with very small diameter springs of fine wire.

But with 0.013" music wire, I'm having trouble getting the right arbor
size for a large-diameter spring. At anything near the desired size, the
wire is only slightly bent by the process; so I know I'll need a MUCH
smaller arbor -- but how small?

I need a spring es-aKly 5/8" o.d., 1-7/8" long, of twelve turns of
0.013" phosphated steel music wire.

Oh -- only 5/8". The way you were going on, I was picturing
something like 5" to 10" diameter.

Anyone have a rule-of-thumb for sizing the arbor for fine wire sizes?

Or, am I stuck trying 15-20 different diameters until something just
works?

Why not try just a few turns on 1/2" and 3/8" and measure what
you get. That will probably let you calculate something quite close to
your needs. Maybe it will show you that you need a third try at 1/4",
but I doubt it.

For the really large ones that I was picturing, I would have
suggested three staggered rollers to put a pre-bend into the wire
separate from the arbor.

Good Luck,
DoN.

--
Remove oil spill source from e-mail
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

On Jul 22, 12:57*pm, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:
I need to wind a couple of large-diameter, fine wire springs. *(light
force, balancing device. *And I cannot find any "stock" springs that fit
the bill)

I have good luck with wire that is larger, and whose elastic limit is
mightily overcome by the radius of the arbor. *Then they relax only a
little, and come off the arbor a few percent larger than they were wound. *
I have OK luck with very small diameter springs of fine wire.

But with 0.013" music wire, I'm having trouble getting the right arbor
size for a large-diameter spring. *At anything near the desired size, the
wire is only slightly bent by the process; so I know I'll need a MUCH
smaller arbor -- but how small?

I need a spring es-aKly 5/8" o.d., 1-7/8" long, of twelve turns of
0.013" phosphated steel music wire.

Anyone have a rule-of-thumb for sizing the arbor for fine wire sizes?

Or, am I stuck trying 15-20 different diameters until something just
works?

LLoyd

can you do this quick&dirty by having a roller (narrow guided with the
wire or wide, length of the arbor) press the wire against the arbor
right where the wire contacts the arbor? (arbor and roller make a
pinch roller)

dave

Lloyd E. Sponenburgh wrote:
I need to wind a couple of large-diameter, fine wire springs. (light
force, balancing device. And I cannot find any "stock" springs that fit
the bill)

I have good luck with wire that is larger, and whose elastic limit is
mightily overcome by the radius of the arbor. Then they relax only a
little, and come off the arbor a few percent larger than they were wound.
I have OK luck with very small diameter springs of fine wire.

But with 0.013" music wire, I'm having trouble getting the right arbor
size for a large-diameter spring. At anything near the desired size, the
wire is only slightly bent by the process; so I know I'll need a MUCH
smaller arbor -- but how small?
Its not the diameter, its the music wire. This is hardened, which
causes this exact problem. it makes great springs, but is HELL to make
a permanent bend in. Ever re-string a guitar? Getting the wire to take
a bend on the tuning pegs is a real challenge, and trying to not get the
wire poked all the way through your finger.

I think you will have to experiment, but you can wind the wire around
drill bit shanks to find the magic size that results in the desired
relaxed coil diameter.

Jon

On Thu, 22 Jul 2010 11:57:02 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

I need to wind a couple of large-diameter, fine wire springs. (light
force, balancing device. And I cannot find any "stock" springs that fit
the bill)

I have good luck with wire that is larger, and whose elastic limit is
mightily overcome by the radius of the arbor. Then they relax only a
little, and come off the arbor a few percent larger than they were wound.
I have OK luck with very small diameter springs of fine wire.

But with 0.013" music wire, I'm having trouble getting the right arbor
size for a large-diameter spring. At anything near the desired size, the
wire is only slightly bent by the process; so I know I'll need a MUCH
smaller arbor -- but how small?

I need a spring es-aKly 5/8" o.d., 1-7/8" long, of twelve turns of
0.013" phosphated steel music wire.

Anyone have a rule-of-thumb for sizing the arbor for fine wire sizes?

Or, am I stuck trying 15-20 different diameters until something just
works?

LLoyd


Years ago a place I worked made some springs for some project or
another. The Shop Foreman, who seemed to know what he was doing, had
us build a gizmo, that fitted in the tool post and tensioned the wire
as it wound onto the arbor. It has been a long time but I seem to
remember that the arbor was basically the approximate desired inside
diameter of the spring and the turns per inch was governed by the
carriage, driven by the lead screw.

I also seem to remember that tension on the wire was the critical
point in the whole operation.

Cheers,

John D. Slocomb
(jdslocombatgmail)

J. D. Slocomb fired this volley in
:

Years ago a place I worked made some springs for some project or
another. The Shop Foreman, who seemed to know what he was doing, had
us build a gizmo, that fitted in the tool post and tensioned the wire
as it wound onto the arbor. It has been a long time but I seem to
remember that the arbor was basically the approximate desired inside
diameter of the spring and the turns per inch was governed by the
carriage, driven by the lead screw.

I also seem to remember that tension on the wire was the critical
point in the whole operation.



Think relative diameter of the wire and the arbor.

I'm working with 13-thou wire to finish out to a 5/8" o.d. spring.

The rules for "thick wire" don't hold.

But the problem's solved.

LLoyd

On Thu, 22 Jul 2010 11:57:02 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

I need to wind a couple of large-diameter, fine wire springs. (light
force, balancing device. And I cannot find any "stock" springs that fit
the bill)

I have good luck with wire that is larger, and whose elastic limit is
mightily overcome by the radius of the arbor. Then they relax only a
little, and come off the arbor a few percent larger than they were wound.
I have OK luck with very small diameter springs of fine wire.

But with 0.013" music wire, I'm having trouble getting the right arbor
size for a large-diameter spring. At anything near the desired size, the
wire is only slightly bent by the process; so I know I'll need a MUCH
smaller arbor -- but how small?

I need a spring es-aKly 5/8" o.d., 1-7/8" long, of twelve turns of
0.013" phosphated steel music wire.

Anyone have a rule-of-thumb for sizing the arbor for fine wire sizes?

Or, am I stuck trying 15-20 different diameters until something just
works?

LLoyd

Depending on where you are, I might be able to help....I have a spring
winder sitting on a bench at work....if you have the wire and can get
to southern wisconsin, I suspect we could get you a spring wound.

Mike