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23-02-2004, 01:20 PM
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#61
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Re: Why would a garage door torsion spring break & is two better than one?
"Michael Baugh" <baughfam@bellsouth.net> wrote in message
news:9EHYb.23172$kR3.13220@bignews4.bellsouth.net. ..
> Same here. 12 years at this house, the double-wide 8' tall wooden door is
> sagging, no idea how long it's been here before me. Temperatures below
> freezing routinely, and no broken springs from the cold.
>
> SHARX. <SHARX@SHARXTANKnospam.com> wrote in message
> news:FfFYb.25447$n17.16190@clgrps13...
> > > average, for the lows respectively. The record all time
> > > February low in San Jose was 26 degrees, set momentarily
> > > in 1989 just before dawn. Now we're talking cold! Garage
> > > door torsion springs were snapping all over the valley.
>
> > Hard to believe a barely freezing temp. would cause a spring to break.
> That
> > would be a WARM winter day up here. No springs ever broken in my 17
years
> in
> > this house. HEAVY double wide wooden door.
==============
We were talking about torsion style springs here as used on roll-up doors.
Is that what you're referring to or is it the tension style springs used on
flat panel doors. Different situation!
SJF
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23-02-2004, 01:21 PM
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#62
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Re: Why would a garage door torsion spring break & is two better than one?
It's the spring that gets twisted, rather than stretched as an extension.
For a 5-segment panel door. Of over 400 pounds.
SJF <SJF@nospam.com> wrote in message news:bJOYb.9939$tM5.4945@fed1read04...
> We were talking about torsion style springs here as used on roll-up doors.
> Is that what you're referring to or is it the tension style springs used
on
> flat panel doors. Different situation!
>
> SJF
>
>
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23-02-2004, 01:27 PM
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#63
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Re: Why would a garage door torsion spring break & is two better than one?
THANKS TO ALL OF YOU, my garage door torsion spring repair was a success!
In summary, I labored from about 3 pm to nightfall today in order to perform
my very first sectional overhead garage door torsion spring counterbalance
replacement task. (Research took more than a week, but, that was fun, thanks
mostly to all of you who volunteered to advise me so kindly!)
The garage door now opens fine. As a bonus, it seems to make MUCH less noise
when the electric garage door opener (aka GDO) runs than it did before
(I'm not sure exactly why the GDO would sound smoother & quieter though.)
As only one counterbalance torsion spring was originally installed, I was
afraid to replace that with two springs. Nothing in this thread gave me
any calculations that I could follow in their footsteps to replace the
single-spring style with a dual-spring style.
So I merely replaced the original non-galvanized torsion spring with an
equivalent sized galvanized spring which costs $55.00 (plus tax) from
a local supplier (including the winding cone & stationary end).
FYI, some Internet torsion-spring suppliers I researched were:
http://www.overheaddoorparts.com/Spring_chart.htm (800)829-6002
http://www.garage-door.com/SecSpring.htm
http://www.hurleyspring.com/quote/quote4.htm
http://www.jwsgaragedoor.com/springpage.htm
http://www.newcombspring.com/torsn.html
http://www.generalwirespring.com/
http://www.steelbuilding.com/doors/garage_doors.htm
http://centuryspringmfg.com/Springs...on_springs.html
Prices were roughly equivalent, e.g., the actual price I paid was:
$45 For one torsion spring (LH helix, 0.250, 33 inch, 1 3/4 inch ID)
$10 For factory-installed winding and stationary ends
$15 For the winding tools (they would have been much cheaper at Home Depot)
$15 For tax & shipping
$10 For the fluids mentioned below
----
$95 total
Some dimensions:
Garage door: 16 feet wide, 6 foot 9 inches tall, aluminum, 152 pounds
Torsion spring: 33 inches long, 0.250 inch wire, 1 3/4 inch ID, 2 1/4 inch OD,
Left-hand helix, 7 1/2 turns to balance, galvanized
Torsion shaft: 1 inch outside diameter (OD), 17 feet long tension shaft
Torsion shaft clearance: 2 1/2 inches to lowest rafter; 7 1/4 inches to door
Lift drum: Two 4 1/2 inch diameter cable drums, each wound with 0.090 inch
diameter steel lift cables in good condition
Tools required (turned out to be nothing special whatsoever):
To prevent the torsion bar from spinning:
Two 9 inch long vise grips
To remove & replace the winding cone:
Two 18 inch long by 7/16 inch diameter steel winding bars
For the two winding cone square set bolts:
12-point 7/16 inch Craftsman box/open hand wrench (#44694)
For the two center bearing plate hex-head bolts & nuts:
12-point 9/16 inch Craftsman box/open hand wrench (#44696)
For measurements:
1 inch micrometer, 12 inch caliper, 25 foot tape measure
Six foot ladder and halogen shop light
(It's surprisingly dark in there so a flashlight was also used)
Only four basic fluids were employed:
Denco Foamy Garage Door Superlube: (for all the door hinges & door tracks)
Lubriplate Low Temperature Grease: (for the electric door opener worm gear)
SAE 30 motor oil: (a few drops at the torsion spring nylon bearing steel plate)
WD40: (was only used to coat the torsion spring itself to prevent corrosion)
The torsion spring supplier personally described his color code for my shaft as:
Red paint on the winding cone indicated a left-hand spring (vs black for RH)
Gold paint on the last spring turn at the winding cone indicated 0.250 inch
Green paint across the torsion spring was merely to aid in counting turns
About the only steps different than those already published at the site:
http://www.truetex.com/garage.htm
were I used vise grips on the back leg of the track ABOVE THE ROLLER, and
I put my ladder legs ON THE BOTTOM OF THE DOOR to prevent the door from
accidentally flying upward as I wound the springs. Also, I placed my ladder
to the SIDE OF THE TORSION spring (not head on) for what seemed to me to be
obvious safety reasons. And, of course, since mine was a single spring system,
I had no need to unwind the additional spring, nor to balance the two.
My original garage door model appears to be a "Model RP 37 Torsion Spring"
by the manufacturer Wayne Dalton, Kinnear Division at POB 82266, Portland,
Oregon, 97282.
I shot photos of every step in the process; but I do not know how to post
these photos to google groups so that you can see them:
http://groups.google.com/groups?group=alt.home.repair
Again, thanks to everyone for the help! About the only thing I wished we'd
have resolved is how, mathematically, to convert a single-spring system to
a dual-spring system (I assume the safety factor is increased with dual
springs as both wouldn't go at the same time & the durability factor might
or might not increase as there are TWO items to break (KISS), yet each one
holds only half the load).
Klutz
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23-02-2004, 01:27 PM
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#64
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Re: Why would a garage door torsion spring break & is two better than one?
brokenklutz@yahoo.com (DIY Klutz) erred by stating:
> Garage door: 16 feet wide, 6 foot 9 inches tall, aluminum, 152 pounds
My mistake. Light steel (not aluminum) frame. With fiberboard panels.
And, of course, it's otherwise uninsulated (temp only drops to 40 F here 
I tried to find the PDF of the RP 37 garage door manual (1-888-827-DOOR) at:
http://www.wayne-dalton.com/files/m...nuals_Steel.asp
Unfortunately, Wayne Dalton doesn't seem to have manuals for the
RP 37 anymore (they have a 47 model but it's of wood constructionb).
But, torsion-spring manuals (for the 7000/8000 series) seemed similar:
http://www.wayne-dalton.com/files/m...sion-301909.pdf
http://www.wayne-dalton.com/files/M...rsionSpring.pdf
http://www.wayne-dalton.com/files/m...ning-248446.pdf
These provide valuable information, such as torque specs for the set bolts.
For reference, I contacted three local south bay suppliers for quotes.
All were around $150 dollars; therefore, in hindsight, you guys were mostly
correct in that it wasn't worth doing myself from a dollars/risk perspective.
But, knowledge gained helps me better understand safety factors (for example,
the kids are NO LONGER ALLOWED to hit the GDO button and then make a mad dash
for the door, bending down from the lowering door and jumping over the trip
sensor). Also, the knowledge gained helps me maintain the garage door
components, (e.g., timely lubrication of hinges, worm gear, rollers, etc.).
By the way, another maintenance trick I learned along the way was to
CLEAN THE SAFETY SENSOR (mine was blinking incessently, perhaps from the
cobwebs, before I wiped them clean). I still don't know what I did to make
it run so very much smoother, but, I guess that's just the added bonus for
an afternoon of DIY work.
DIY Klutz
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23-02-2004, 01:27 PM
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#65
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Re: Why would a garage door torsion spring break & is two better than one?
"DIY Klutz" <brokenklutz@yahoo.com> wrote in message
news:1dfb2e58.0402202251.1660aba4@posting.google.c om...
------ clipped ------
> Again, thanks to everyone for the help! About the only thing I wished we'd
> have resolved is how, mathematically, to convert a single-spring system to
> a dual-spring system (I assume the safety factor is increased with dual
> springs as both wouldn't go at the same time & the durability factor might
> or might not increase as there are TWO items to break (KISS), yet each one
> holds only half the load).
>
> Klutz
Durability factor --
I vaguely recall that, in metal fatigue, the number of stress cycles before
failure increases exponentially as the loading is decreased. So sharing the
load between two springs *should* greatly increase their service lives. Of
course, this assumes there are no flaws in the metal which may be a stretch.
Also, that lighter springs were not used because they are paired.
My own double door has two springs. The first failed at four years.
SJF
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23-02-2004, 01:28 PM
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#66
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Re: Why would a garage door torsion spring break & is two better than one?
brokenklutz@yahoo.com (DIY Klutz) wrote in message news:<1dfb2e58.0402210619.2dee481@posting.google.com>...
> brokenklutz@yahoo.com (DIY Klutz) erred by stating:
> > Garage door: 16 feet wide, 6 foot 9 inches tall, aluminum, 152 pounds
>
> My mistake. Light steel (not aluminum) frame. With fiberboard panels.
> And, of course, it's otherwise uninsulated (temp only drops to 40 F here
>
> I tried to find the PDF of the RP 37 garage door manual (1-888-827-DOOR)
I'm embarrassed; the Internet shows everyone what I don't know!
And, I'm amazed myself at how much I took the garage door for granted.
Heck, I didn't even know it had springs; and I just found out I don't
even know what its made up of. Thank God for Internet friends ...
Richard, kindly emailed me a complete list of doors, from which we've
determined mine to be a "FOAMCORE 37" from Wayne Dalton. Despite my prior
assumption otherwise, this "Wayne Dalton" steel door actually *does* have
insulation (to weather the frigid bay area 40-degree cold spells, I guess
One of the PDF catalogs Richard kindly emailed me states:
"Insulation with and (sic) R value of 5.62 is chemically bonded to
the steel surface"
The insulation which I thought was some kind of painted fiberboard is
listed in Richard's catalog as a "foamed-in-place polyurethane core",
creating "an exterior surface .5625 inches thick". The catalog goes
further to state this is "30-times as thick as typical 0.19 inch steel
doors".
Uh, is thicker better? Why would I care? I suspect the R value is all
that really matters, not the thickness, per se.
Apparently the "RP" part is merely the embossing of the exterior panels
(where RP stands for "Raised Panel").
It's amazing what you learn by doing something; and what you don't learn
if you let others do the job for you. I suspect, even if I hire out a
contractor next time (remember, it really wasn't worth it financially),
I'll be in a position to make a much better decision. And, if I purchase
a garage door in the future, I'll know a bit more than I did when I heard
that CRACK just a short while ago.
Thanks to everyone ... if you can answer why it would matter the thickness
of the door ... or if you can help me with a calculation for replacing a
single-torsion spring system with a dual torsion spring system (if that
is indeed better) ... that would be nice.
Klutz
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23-02-2004, 01:28 PM
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#67
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Re: Why would a garage door torsion spring break & is two better than one?
DIY Klutz wrote:
> brokenklutz@yahoo.com (DIY Klutz) wrote in message
> news:<1dfb2e58.0402210619.2dee481@posting.google.com>...
>> brokenklutz@yahoo.com (DIY Klutz) erred by stating:
>>> Garage door: 16 feet wide, 6 foot 9 inches tall, aluminum, 152
>>> pounds
>>
>> My mistake. Light steel (not aluminum) frame. With fiberboard panels.
>> And, of course, it's otherwise uninsulated (temp only drops to 40 F
>> here
>>
>> I tried to find the PDF of the RP 37 garage door manual
>> (1-888-827-DOOR)
>
> I'm embarrassed; the Internet shows everyone what I don't know!
> And, I'm amazed myself at how much I took the garage door for granted.
> Heck, I didn't even know it had springs; and I just found out I don't
> even know what its made up of. Thank God for Internet friends ...
>
> Richard, kindly emailed me a complete list of doors, from which we've
> determined mine to be a "FOAMCORE 37" from Wayne Dalton. Despite my
> prior
> assumption otherwise, this "Wayne Dalton" steel door actually *does*
> have
> insulation (to weather the frigid bay area 40-degree cold spells, I
> guess
>
> One of the PDF catalogs Richard kindly emailed me states:
> "Insulation with and (sic) R value of 5.62 is chemically bonded to
> the steel surface"
>
> The insulation which I thought was some kind of painted fiberboard is
> listed in Richard's catalog as a "foamed-in-place polyurethane core",
> creating "an exterior surface .5625 inches thick". The catalog goes
> further to state this is "30-times as thick as typical 0.19 inch steel
> doors".
>
> Uh, is thicker better? Why would I care? I suspect the R value is all
> that really matters, not the thickness, per se.
>
Ask your wife.
> Apparently the "RP" part is merely the embossing of the exterior
> panels (where RP stands for "Raised Panel").
>
> It's amazing what you learn by doing something; and what you don't
> learn
> if you let others do the job for you. I suspect, even if I hire out a
> contractor next time (remember, it really wasn't worth it
> financially),
> I'll be in a position to make a much better decision. And, if I
> purchase
> a garage door in the future, I'll know a bit more than I did when I
> heard
> that CRACK just a short while ago.
>
> Thanks to everyone ... if you can answer why it would matter the
> thickness
> of the door ... or if you can help me with a calculation for
> replacing a
> single-torsion spring system with a dual torsion spring system (if
> that
> is indeed better) ... that would be nice.
>
> Klutz
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23-02-2004, 01:28 PM
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#68
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Re: Why would a garage door torsion spring break & is two better than one?
(By the way, I always thought the GARAGE DOOR OPENER is what opened the
door. I never realized it was the torsion spring that opened the door. Duh!)
Now that I know more about the garage door, I can dig deeper into specifics
as to whether or not my existing torsion spring was overextended & whether
or not a torsion spring redesign (dual spring or larger size) is warranted.
The original spring was 33 inches long, 0.250 inch wire, left-hand helix, with
an ID of 1 3/4 inches and an OD of 2 1/4 inches on a 1 inch OD torsion rod.
Q: CAN SOMEONE HELP ME UNFUDDLE THE INFORMATION RELAYED BELOW?
This site http://diygaragerepair.com/sectionalsprings.htm provides a
table of suggested torsion springs to use with various sized doors:
1 3/4 inch inside diameter 1 3/4 inch inside diameter
Foam Insulated Sectional Door Non Insulated Sectional Door (25g)
8'x6'6" - 31 3/4 Yellow 8x6'6" - 26 3/4 Yellow
8'x7' - 31 3/4 Yellow 8x7 - 26 3/4 Yellow
8'x7'6" - 31 3/4 Yellow --- --- --- --- --- ---
8'x8' - 31 3/4 Yellow 8x8 - 31 1/2 White
9'x6'6" - 31 3/4 Yellow 9x6'6" - 26 3/4 Yellow
9'x7' - 31 3/4 Yellow 9x7 - 26 3/4 Yellow
9'x7'6" - 31 3/4 Yellow --- --- --- --- --- ---
9'x8' - 31 3/4 Yellow 9x8 - 31 1/2 White
10'x6'6" - 31 3/4 Yellow 10x6'6" - 28 3/4 Red
10'x7' - 31 3/4 Yellow 10x7 - 28 3/4 Red
10'x8' - 31 3/4 Yellow 10x8 - 31 Red
12'x6'6" - 31 3/4 Yellow --- --- --- --- --- ---
12'x7' - 31 3/4 Yellow 12x7 - 28 3/4 Brown
12'x8' - 28 3/4 White --- --- --- --- --- ---
14'x6'6" - 28 3/4 Red --- --- --- --- --- ---
14'x7' - 28 3/4 Red 14x7 - 31 Green
14'x8' - 28 3/4 Red --- --- --- --- --- ---
15'x7 - 28 3/4 Red 15x7 - 33 Green
15'8"x7' - 28 3/4 Red 15'8"x7 - 34 1/4 Gold
--- --- --- --- --- --- 15x8 - 26 3/4 Yellow (Pair)
16'x6'6" - 31 1/4 Brown 16x6'6" - 34 1/4 Gold
16'x7' - 31 1/4 Brown 16x7 - 34 1/4 Gold
16'x7'6" - 31 1/4 Brown --- --- --- --- --- ---
16'x8' - 31 1/4 Brown 16x8 - 26 3/4 Yellow (Pair)
18'x6'6" - 34 1/4 Gold 18x6'6" - 26 White (Pair)
18'x7' - 34 1/4 Gold 18x7 - 26 White (Pair)
18'x8' - 26 3/4 Yellow (Pair) 18x 8 - 31 Red (Pair)
Q1: What does the color mean here (where's the cross reference)?
(Does the color indicate the wire thickness?)
Q2: Can it be this simple? (where's the actual door weight)?
(Although the weight is inherent in the size & insulation; but,
don't materials, e.g., steel vs wood make a huge difference?)
However, this chart is all I have so far to determine if the existing
spring is the correct one for the application (I've no experience).
Given barely insulated garage door is 6 foot 9 inches in height
(which isn't on the charts above) but, interpolated from the chart
apparently suggests a single torsion spring design of dimensions:
31 1/4 inches long, Brown (whatever brown indicates here)
I assume this indicates the torsion spring listed as:
1.75 x 0.234 x 31.25 = $27.60 (LH helix, with cone, + $6.90 shipping)
Given that I replaced the original spring of the dimensions:
1.75 x 0.250 x 33 = $29.20 (LH helix, with cone, + 7.80 shipping)
I'd have to guess the existing spring (33 incher) is at least adequate.
There's nothing here to suggest a dual spring is warranted though.
Is there a better location on the web for DETERMINING THE CORRECT SPRING?
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23-02-2004, 01:29 PM
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#69
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Re: Why would a garage door torsion spring break & is two better than one?
>
> Durability factor --
>
> I vaguely recall that, in metal fatigue, the number of stress cycles before
> failure increases exponentially as the loading is decreased. So sharing the
> load between two springs *should* greatly increase their service lives. Of
> course, this assumes there are no flaws in the metal which may be a stretch.
> Also, that lighter springs were not used because they are paired.
>
> My own double door has two springs. The first failed at four years.
>
> SJF
Actually the number of the springs has nothing to do with how long
they last. It is all a matter of the wire size, the length of the
spring, & the inside diameter of the spring. The bigger the wire size,
the longer the spring will be (when keeping the same dia) & hence the
longer the spring will last regardless if you have one, two, or even
more springs. Actually with the springs that some manufacturers use
now the one long spring will usually last alot longer then the two
short ones some mfgs use.
The torque (lifting power) of the spring is all a matter of the weight
of the door & the size of the cable drum & the total torque can be
divided by any number of springs that you want as long as they will
fit on the shaft, but you should use springs that are rated for at
least 10,000 cycles or more. Good repairmen look the spring up on a
chart or use spring engineering software in order to determine the
number of cycles to make sure they are not going below the 10,000
cycles.
Doordoc
www.DoorsAndOpeners.com
Doordoc
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23-02-2004, 01:30 PM
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#70
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Re: Why would a garage door torsion spring break & is two better than one?
> Uh, is thicker better? Why would I care? I suspect the R value is all
> that really matters, not the thickness, per se.
if you have kids throwing balls at your garage door, youll care about
thickness. if ya dont, then ya wont.
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23-02-2004, 01:30 PM
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#71
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Re: Why would a garage door torsion spring break & is two better than one?
brokenklutz@yahoo.com (DIY Klutz) wrote in message news:<1dfb2e58.0402211524.6013f908@posting.google.com>...
> Q: CAN SOMEONE HELP ME UNFUDDLE THE INFORMATION RELAYED BELOW?
>
> This site http://diygaragerepair.com/sectionalsprings.htm provides a
> table of suggested torsion springs to use with various sized doors:
>
> 1 3/4 inch inside diameter 1 3/4 inch inside diameter
> Foam Insulated Sectional Door Non Insulated Sectional Door (25g)
> 8'x6'6" - 31 3/4 Yellow 8x6'6" - 26 3/4 Yellow
> 8'x7' - 31 3/4 Yellow 8x7 - 26 3/4 Yellow
> 8'x7'6" - 31 3/4 Yellow --- --- --- --- --- ---
> 8'x8' - 31 3/4 Yellow 8x8 - 31 1/2 White
> 9'x6'6" - 31 3/4 Yellow 9x6'6" - 26 3/4 Yellow
> 9'x7' - 31 3/4 Yellow 9x7 - 26 3/4 Yellow
> 9'x7'6" - 31 3/4 Yellow --- --- --- --- --- ---
> 9'x8' - 31 3/4 Yellow 9x8 - 31 1/2 White
> 10'x6'6" - 31 3/4 Yellow 10x6'6" - 28 3/4 Red
> 10'x7' - 31 3/4 Yellow 10x7 - 28 3/4 Red
> 10'x8' - 31 3/4 Yellow 10x8 - 31 Red
> 12'x6'6" - 31 3/4 Yellow --- --- --- --- --- ---
> 12'x7' - 31 3/4 Yellow 12x7 - 28 3/4 Brown
> 12'x8' - 28 3/4 White --- --- --- --- --- ---
> 14'x6'6" - 28 3/4 Red --- --- --- --- --- ---
> 14'x7' - 28 3/4 Red 14x7 - 31 Green
> 14'x8' - 28 3/4 Red --- --- --- --- --- ---
> 15'x7 - 28 3/4 Red 15x7 - 33 Green
> 15'8"x7' - 28 3/4 Red 15'8"x7 - 34 1/4 Gold
> --- --- --- --- --- --- 15x8 - 26 3/4 Yellow (Pair)
> 16'x6'6" - 31 1/4 Brown 16x6'6" - 34 1/4 Gold
> 16'x7' - 31 1/4 Brown 16x7 - 34 1/4 Gold
> 16'x7'6" - 31 1/4 Brown --- --- --- --- --- ---
> 16'x8' - 31 1/4 Brown 16x8 - 26 3/4 Yellow (Pair)
> 18'x6'6" - 34 1/4 Gold 18x6'6" - 26 White (Pair)
> 18'x7' - 34 1/4 Gold 18x7 - 26 White (Pair)
> 18'x8' - 26 3/4 Yellow (Pair) 18x 8 - 31 Red (Pair)
>
Depends if they are using the standard DASMA color chart or not to
know what the colors mean. DASMA uses colors so one can tell the wire
size without measuring it.
However I would question why anyone would say that a 12x7 & a 8x7 uses
the same spring when the 12' door obviously would weigh 1-1/2 times
more then the 8'. Also as you noted there is no mention on the weight
of the door on the insulated chart (the non-insulated says 25g which
may mean 25 gauge) and all doors do not weigh the same. Your
"foamcore" door is 32 gauge which would obviously weigh alot less then
a 25 gauge insulated door and using the wrong spring would either
cause the door to fly off the floor like a rocket or to lift like a
rock. It's not a matter of how many turns you put on the spring. All
7' tall doors w/ 4" drums (measure where the cable wraps & not the
outside edge) will have approx 7-1/2 turns (1 turn per foot) whether
the door weighs 50# or 500#. The difference is totally in the IPPT
(inch pounds per turn)of the spring.
Doordoc
www.DoorsAndOpeners.com
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25-03-2004, 10:39 PM
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#72
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Re: Why would a garage door torsion spring break & is two better than one?
doordoc@prodigy.net (Doordoc) wrote in message news:<63b5749d.0402220823.79419a69@posting.google.com>...
Regarding: Torsion spring color codes in listed replacement tables:
> Depends if they are using the standard DASMA color chart or not to
> know what the colors mean. DASMA uses colors so one can tell the wire
> size without measuring it.
Is it just me or have others never heard of DASMA before?
If it's not just me, I looked it up for you.
Door & Access Systems Manufacturers Association.
http://www.dasma.com
Which has tidbits (but not much detail) on tantalizing stuff such as:
Standard for Counterbalance Systems on Residential Sectional Garage
Standard Method for Testing Garage Door Life Cycling Performance
Standard Method for Determination of Structural Performance
etc.
Likewise, the technical tips are light on detail, but, are arousing otherwise:
How to stretch the life of a torsion spring:
http://www.dasma.com/articles/tech/tips38.asp
How to measure a torsion spring:
http://www.dasma.com/articles/tech/tips25.asp
Special attention for single torsion spring systems:
http://www.dasma.com/articles/tech/tips33.asp
Regarding:
> However I would question why anyone would say that a 12x7 & a 8x7 uses
> the same spring when the 12' door obviously would weigh 1-1/2 times
> more then the 8'.
Good point. The table has other irregularities I've noted.
So, we (in this excellent thread) need more TECHNICAL HELP from
the experts out there!
This thread needs more ENGINEERING references & PRACTICAL experience!
> (the non-insulated says 25g which
> may mean 25 gauge)
I was wondering about that g (I knew it wasn't 25 grand or 25 grams).
> It's not a matter of how many turns you put on the spring. All
> 7' tall doors w/ 4" drums (measure where the cable wraps & not the
> outside edge) will have approx 7-1/2 turns (1 turn per foot) whether
> the door weighs 50# or 500#. The difference is totally in the IPPT
> (inch pounds per turn)of the spring.
Very astute. You know your stuff! I measured my drum just now
(actually, from the DASMA site, I should call it a "cable drum")
and this 4 inch cable drum indeed measures 4 and a half inches in
diameter outside edge to outside edge. Who knew?
> Doordoc
Indeed. You know a LOT! I wish others would post with knowledge such
as yours is. I too would love to see a table which tells me if my
boyfriend installed the right single torsion spring when he did mine
this Christmas. How would I know myself if its the right spring?
Ellen
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25-03-2004, 10:41 PM
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#73
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Re: Why would a garage door torsion spring break & is two better than one?
>
> Indeed. You know a LOT! I wish others would post with knowledge such
> as yours is. I too would love to see a table which tells me if my
> boyfriend installed the right single torsion spring when he did mine
> this Christmas. How would I know myself if its the right spring?
>
> Ellen
Thanks for the compliment!
You won't find a easily read table that shows you what you are asking.
The spring & cable drum charts fill a 3-4" notebook. You need to know
the weight of the door, multiply the weight by a multiplier for that
particular drum and that will give you the IPPT that the spring needs
to be. Then you look for a spring with that IPPT and is rated for at
least 10,000 cycles (once up & down) when there is 7 turns on the
spring. So the larger the wire size (measure 10 coils of the spring w/
a tape measure w/o the cones), the longer the spring will be, and the
more cycles the spring will last. We do some commercial doors that
have 100,000 cycles, but that would be overkill on most residential
doors since the springs would outlast the rest of the door.
The easiest way to tell if it is sprung properly is to work the door
by hand & let go of it in different places. The door should stay
fairly close to where you let go & should not drop like a rock or fly
open on it's own.
During spring changes most repairmen will simply measure the existing
spring & match the new spring to the old & therefore they are not
concerned w/ what the door actually weighs. When we need to do spring
engineering we use software which is much faster then reading a bunch
of charts.
To the original post, there is no advantage or reason to replace one
spring w/ two. It does not make the door work any different or better
& in my opinion would be a waste of money since there is nothing to
gain.
Doordoc
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25-03-2004, 10:41 PM
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#74
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Re: Why would a garage door torsion spring break & is two better than one?
doordoc@prodigy.net (Doordoc) wrote in message news:<63b5749d.0402220823.79419a69@posting.google.com>...
> The difference is totally in the IPPT (inch pounds per turn)of the spring.
Since IPPT is so important, I'm trying to derive it for my springs
given the torsion spring formulas in the web site below:
http://www.srl.gatech.edu/education...mer/torsion.htm
Given in that web site that torque (T) equals the stiffness of the
spring (K) times the total number of turns (theta in radians); then
I think I only need to determine the stiffness of my new garage door
torsion spring in order to derive this all important IPPT torque value.
Given I turned my torsion spring 7 1/2 turns; & given theta in radians:
T = K * theta
T = K * (7.5 turns * (2 * pi radians))
So, all I think I need is to find K, the stiffness of the spring,
in order to determine the actual torque it developed in the 7 1/2
turns I twisted the spring before tightening the set bolts.
To find the spring stiffness (K), I used the formula from that web page:
K = d^4 E / 64 D N
where K is the unknown stiffness of my newly installed torsion spring
d is the diameter of the wire (I measured it at 0.256 inches unsprung)
E is the elastic modulus of the steel (I assume 30 million psi)
D is the diameter of the spring itself (I measured 1.740 inches unsprung)
N is the number of coils (I measured 133 total, but only 127 active)
Substituting the values above into the equation from that web page:
K = d^4 E / 64 D N
K = (0.256 inches)^4 * 30 million psi / 64 * 1.740 inches * 127 coils
K = (4.3e-3 inches^4 * 30e6 psi) / (64 * 1.740 inches * 127)
K = 129,000 / 14,224 inch pounds
K = 9 inch pounds (is this the IPPT?)
QUESTION:
Is that calculation correct?
Now back to the torque formula:
T = K * theta
T = (9 inch pounds) * (7.5 turns * (2 * 3.14 radians))
T = 424 inch pounds (i.e., torsion spring develops about 35 foot pounds)
Oh oh. I think this is too high of a value for IPPT isn't it?
If my assumptions are correct, then I might be able to further assume
this torsion spring torque is applied to the torsion bar which is applied
through the circumference of the two four-inch-diameter "DMI 8" cable drums
which lifts the Wayne Dalton Foamcore 37 Raised Panel garage door 7 feet up.
Given the well known formula: Torque = Force times the distance applied
(delta), where the delta is the 2 inch radius of the cable drums), then
substituting my calculated torque value and the known cable drum radius
should be able to lift the 152 pound door:
T = F * delta
F = T / delta
F = 424 inch pounds / 2 inches
F = 212 pounds lifting force
I'm not sure if I should DOUBLE or HALVE that value, given I have two
cable drums.
QUESTION:
Can a garage door torsion spring expert advise me on these calculations?
DIY Klutz
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25-03-2004, 10:42 PM
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#75
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Re: Why would a garage door torsion spring break & is two better than one?
doordoc@prodigy.net (Doordoc) wrote in message news:<63b5749d.0402242104.74e10bcf@posting.google.com>...
We do some commercial doors that
> have 100,000 cycles, but that would be overkill on most residential
> doors since the springs would outlast the rest of the door.
That brings up the question of why only a mere 10,000 cycles?
So many garage door springs seem to be breaking (virtually everyone
in this thread has reported a broken torsion spring), shouldn't I
take that collective experience to indicate 10,000 cycles is far too
few?
Who chose 10,000 anyway? Nobody asked me.
For example, my family uses the garage door as the main entrance to my
humble household. With three kids and active relatives, we cycle the
door probably 20 to 25 times a day easily. That gives me an average life
of less than two years (10,000 cycles / 20 cycles per day = 500 days).
Why wouldn't I want to replace my 10,000 cycle spring with a 20,000 or more?
To see if cost is a factor, I just called two companies from the yellow pages.
I said my torsion spring (singular) broke. Both quoted me the same price.
I asked if it was firm. They said yes (unless other parts were needed).
They didn't even ask what size spring I had! Apparently it doesn't matter.
It seems the cost of the spring (from most posts in this thread) is not
the major factor in the repair process. Perhaps less than twenty dollars
bulk to no more than 50 dollars retail.
Since the total repair cost is three (or more) times that, wouldn't we
save ooodles of money simply by doubling the life of the spring?
Even if that doubled the cost of the spring, we would still save money.
If it tripled the cost of the spring, we'd still save the time and
inconvenience of having our car trapped inside the garage.
Plus the safety factor (for the home owner) would go up.
To see what spring I needed to double the life of my garage door
torsion springs, I just now downloaded the free trial version of
the suggested Windows PC spring calculator:
http://www.sscorp.com/pages/door_downloads.html
As a test, I defined these two replacement springs (one up, one down).
Current Spring: Replacement #1 (up): Replacement #2 (down):
ID = 1.750 inches ID = 1.750 inches ID = 1.750 inches
Wire = .250 inches Wire = 0.2625 inches Wire = 0.2437 inches
Length = 33 inches
The "Solutions 3.0" software instantly calculated the following:
Current Spring: Replacement #1 (up): Replacement #2 (down):
Length = 33 in 41.50 inches 29.25 inches
Max Turns = 7.91 7.91 7.91 turns
IPPT = 45.23 45.23 45.23 in pounds per turn
Active Coils = 127.00 153.41 115.04 active coils
Total Coils = 132 158.41 120.04 total coils
Weight = 11.52 # 15.34 pounds 9.92 pounds
Cycles = 10,000 19,000 cycles 7,000 cycles
The price for these springs is about the same.
For example at the aforementioned web site:
http://www.garagedooropeners.net/door_springs.html
Duty Cycle = 10,000 = $45
Duty Cycle = 19,000 = $45
Duty Cycle = 7,000 = $35
Prices were similar (a bit cheaper) at:
http://www.aaaremotes.com/garagedoorsprings.html
My point is, the 19,000 duty cycle torsion spring is about the same
cost as the 10,000 duty cycle spring. And that 10,000 seems vastly
too low. So, why not go with the 19,000 (or even greater) every time?
What am I missing?
Ellen
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