Forums: Skydiving: Gear and Rigging:
Making Sigma closing loops

 


freestyleleigh  (D 437)

Aug 19, 2011, 6:34 PM
Post #1 of 13 (2001 views)
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Making Sigma closing loops Can't Post

Hi,

I would like to make my own Sigma closing loops. We have the correct line (1000lb spectra) and are using the same washers that were used on our old loops.

They are a simple unit but my question is;

How do you get the spectra through the tiny holes?

I was told by one rigger to use some hand tacking wax thread and pull it through that way but this seems impossible.

There is nowhere to buy these in our country (as far as I know) and the postage on them from the US is much more than the worth of the loop. we have the equiment to make them just this process is inhibiting us from doing so.

Any riggers out there with the gift of the gab?


koppel  (F License)

Aug 20, 2011, 1:13 AM
Post #2 of 13 (1950 views)
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Re: [freestyleleigh] Making Sigma closing loops [In reply to] Can't Post

Its one of the Rigger Black Arts. Its possible to get 1250 lb Spectra through them little holes too Tongue


irishrigger  (D 297)

Aug 20, 2011, 3:07 PM
Post #3 of 13 (1879 views)
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Re: [freestyleleigh] Making Sigma closing loops [In reply to] Can't Post

Hiya,
the easiest way in my opinion is to cut the spectre line with a hot knife.and when you cut the spectra piece cut it at an angle of about 60 degrees. That way you can thread it nice and easy through the holes in the washer.
Rodger


riggerrob  (D 14840)

Aug 21, 2011, 9:50 PM
Post #4 of 13 (1776 views)
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Re: [irishrigger] Making Sigma closing loops [In reply to] Can't Post

Another method is to use a piece of E-Thread as a pull-up cord.


RIGGER  (D 7933)

Aug 22, 2011, 1:09 AM
Post #5 of 13 (1744 views)
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Re: [freestyleleigh] Making Sigma closing loops [In reply to] Can't Post

Smile Hi

FYI the Sigma main closing loop MUST came from UPT even it's a main container item which is not TSO'd.

Please see the attachment from the manual - I boxed the "WARNING" statement.

The loop spec. are critical & they must be accurate.

*** The only way to mfg. the loop is to have the Approval from UPT & the drawing.

The loop have very specific measurements, finger trap method & a special sewing method.

Do not play with "I can do it - no issues"

They does not cost too much & Air Mail should be low - check with UPT if there are any in your side.

Tandem operation makes money & if you calculate the loop cost per no. of jumps on a loop + shipping you still have a huge profit same for other parts which must be originals from UPT.

Be Safe !!!


(This post was edited by RIGGER on Aug 22, 2011, 1:53 AM)
Attachments: SIGMA MANUAL 2005-MAIN C.LOOP.jpg (111 KB)


ronny2

Aug 22, 2011, 7:46 AM
Post #6 of 13 (1709 views)
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Re: [RIGGER] Making Sigma closing loops [In reply to] Can't Post

Hi shlomo, I know what you mean, but what about this?

http://www.cpsworld.com/tech_pdfs/RWS/WI-038_Rev.0-Sigma1290.pdf


jerolim  (F License)

Aug 22, 2011, 8:13 AM
Post #7 of 13 (1700 views)
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Re: [ronny2] Making Sigma closing loops [In reply to] Can't Post

thanks for the post - buahahahaha (evil laugh) Tongue.


pchapman  (D 1014)

Aug 22, 2011, 8:29 AM
Post #8 of 13 (1694 views)
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Re: [ronny2] Making Sigma closing loops [In reply to] Can't Post

In reply to:
http://www.cpsworld.com/tech_pdfs/RWS/WI-038_Rev.0-Sigma1290.pdf

So that demonstrates that 'build your own' instructions for loops exist, invalidating the argument that only the factory is able to produce such things. (...Whether or not any particular person can build any particular item to the required degree of accuracy.)

However, in this case the pdf instructions are for a military Sigma-style container, that uses a 'pulley closing loop' different from our civvy Sigmas ( 7.5" not 8.5").

Their loop system:
http://www.cpsworld.com/...y%20closing_loop.pdf

So, where are the civilian Sigma loop instructions? Smile


(This post was edited by pchapman on Aug 22, 2011, 8:31 AM)


RIGGER  (D 7933)

Aug 22, 2011, 12:14 PM
Post #9 of 13 (1657 views)
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Re: [ronny2] Making Sigma closing loops [In reply to] Can't Post

Smile Hi

CPS deal with the Military only & the Military has a system that is very different from the civil world including tests, rigging & so on.

The instructions you point on are NOT VALID for the civil sigma & should NOT be followed at all.

We use for the Sigma V13 with Sigma 370 main a loop which is 8.5" long.

Sport market/world & the Military world are two different planets with different specifications.

Be Safe !!!


ronny2

Aug 22, 2011, 11:35 PM
Post #10 of 13 (1607 views)
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Re: [RIGGER] Making Sigma closing loops [In reply to] Can't Post

Sport market/world & the Military world are two different planets with different specifications

We are also from the planet "world" and we jumping the same "Sigma" system

Sigma MM 14
Main: Silhouette 330
Reserve: Silhouette 335
Main loop: 8.5" long


RIGGER  (D 7933)

Aug 23, 2011, 2:15 AM
Post #11 of 13 (1592 views)
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Re: [ronny2] Making Sigma closing loops [In reply to] Can't Post

Smile Hi

I like that we are in the same "world" planet - I was pointing on 2 different training/thechnical systems = Civilian & Military even the parachuting systems might be the same or close to that.

The military gets approvals from CPS (PD, UPT, SPP) which the civil market might not get & it could be from technical & liability reasons.

The military have a more organized rigging system which is very clear for yes & no.

Cheers


(This post was edited by RIGGER on Aug 23, 2011, 2:17 AM)


jerolim  (F License)

Aug 25, 2011, 1:58 AM
Post #12 of 13 (1497 views)
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Re: [pchapman] Making Sigma closing loops [In reply to] Can't Post

I have done some reverse engineering. I have marked and disassembled old Sigma closing loop (civil). I have found that it is made in same fashion as in posted document. So you can use steps 1-10 from this document http://www.cpsworld.com/tech_pdfs/RWS/WI-038_Rev.0-Sigma1290.pdf

Regarding length my closing loop (before disassembly) was 22 cm long. This is 8,75 " = 8 3/4 long ! So it looks like this markings from step 1 ( 07 7 - 1515 23 ) are correct.
Because final loop size will be 8 3/4". This is the math : From marks 15 3/4" to mark 7" (15 3/4" - 7" = 8 3/4") equals 8 3/4".

At last picture lenght says 7 1/2" this can be true only if spectra schrinks because it wider after finger trapping !!!

Any way I'll check what are my markings on old disassembled loop and I'll let you know.

Stitch pattern looks like one from step 10 and I have tried to break picked thread with fish scale - it broke at 4 kilos. So, it is definitely thread is E type. Stitch pattern has to be done neatly and one has to pay attention to thread tension if you want to have smooth (less friction) loop at the end.

I don't know if silicon based lubricant (from cypres kit) needs to be applied or not ?


(This post was edited by jerolim on Aug 25, 2011, 2:06 AM)


jerolim  (F License)

Aug 25, 2011, 10:19 AM
Post #13 of 13 (1452 views)
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Re: [jerolim] Making Sigma closing loops [In reply to] Can't Post

Hi, spectra schrinks after finger trapping.

This are measures in centimeters (for first picture) :
0-21-22-45-47-68

So it is something like
0- 8 1/4" - 8 2/3" - 17 3/4" - 18 2/4" - 26 3/4 "
in inches.

You can play with this numbers maybe everything needs to be shorter a few milimeters. Anyway result will be around 22 cm = 8,5 "


(This post was edited by jerolim on Aug 25, 2011, 10:22 AM)



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