Sewn eyes, help me understand strength

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Thanks much for the report. sounds like you are on the right track.

Any links to the thread and needle sources?

Any pics of stages in the hand sewing?

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Over the weekend filed down the leather cutting needle that came with my Speedy Stitcher sewing awl to create a reasonable facsimile of a ball tipped needle, what I'm sewing with now. I received my first order of real ball tips last week and the size (7x3 250) is size gigantic, too big. I've ordered again for two sizes, I think one of them will be spot on. I've ordered several different types of rated thread at a couple sizes, by the end of this week I should have an excellent spec for a needle and thread and can document the sewing process. So stay tuned, better to wait until I have the best information assembled.
-AJ
 
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Thanks much for the report. sounds like you are on the right track.

Any links to the thread and needle sources?

Any pics of stages in the hand sewing?

[/ QUOTE ]

Over the weekend filed down the leather cutting needle that came with my Speedy Stitcher sewing awl to create a reasonable facsimile of a ball tipped needle, what I'm sewing with now. I received my first order of real ball tips last week and the size (7x3 250) is size gigantic, too big. I've ordered again for two sizes, I think one of them will be spot on. I've ordered several different types of rated thread at a couple sizes, by the end of this week I should have an excellent spec for a needle and thread and can document the sewing process. So stay tuned, better to wait until I have the best information assembled.
-AJ

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I am more than happy to wait and let you do all the work of sorting things out. thanks for the updates
 
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TBH -There is a better speedy stitcher tool available with a solid handle and a good supplier...based in the uk though, airmail would around $5 for one

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Nice looking tool, good needle selection too. One thing I like about the SS is I can take the bobbin out of the handle then put the metal cap back on the bobbin compartment. Then I put my thread roll on the floor or in my sewing bag on the floor. I run the thread up out of the bag, then into the handle through the small hole in the bobbin cap, through the bobbin compartment and then out the small hole in the side of the handle, around the little tensioner piece and finally through the needle. Keeps it all very neat while I'm sewing and I never need to wind the bobbin
-AJ
 
moss said:
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TBH -There is a better speedy stitcher tool available with a solid handle and a good supplier...based in the uk though, airmail would around $5 for one

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Nice looking tool, good needle selection too. One thing I like about the SS is I can take the bobbin out of the handle then put the metal cap back on the bobbin compartment. Then I put my thread roll on the floor or in my sewing bag on the floor. I run the thread up out of the bag, then into the handle through the small hole in the bobbin cap, through the bobbin compartment and then out the small hole in the side of the handle, around the little tensioner piece and finally through the needle. Keeps it all very neat while I'm sewing and I never need to wind the bobbin
-AJ
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A
moss said:
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Thanks much for the report. sounds like you are on the right track.

Any links to the thread and needle sources?

Any pics of stages in the hand sewing?

[/ QUOTE ]

Over the weekend filed down the leather cutting needle that came with my Speedy Stitcher sewing awl to create a reasonable facsimile of a ball tipped needle, what I'm sewing with now. I received my first order of real ball tips last week and the size (7x3 250) is size gigantic, too big. I've ordered again for two sizes, I think one of them will be spot on. I've ordered several different types of rated thread at a couple sizes, by the end of this week I should have an excellent spec for a needle and thread and can document the sewing process. So stay tuned, better to wait until I have the best information assembled.
-AJ
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AJ, Did you come to a conclusion on best thread and needle for the Speedy Stitcher for this purpose? Thanks! J
 
Here's a good thread where I posted everything I know to-date with links to photos etc.
Sewn eye documentation

Read both pages and click on the links to various photos, I'm waxing my own thread with beeswax, using the same size thread 75 lb. strength for 11mm and 10mm eyes, using the 45 lb. strength polyester thread that comes with the Speedy Stitcher for 8mm eyes.

I've just about worn out out a 10mm OP sewn eye cord, an 8mm OP sewn eye cord and it's getting to be time to retire my 150' Tachyon with a sewn eye on one end. I will have all these pull tested on retirement. I couldn't bear to pull test them new since I knew they were quite a bit stronger than my previous generation of sewn eyes (pre-compressed, stronger thread, better technique) and I put considerable effort into making them.

As I suspected they would, the eyes very much outlasted the cordage, no changes in the stitching or eyes. They look and feel same as the day they were sewn, the hitch cords were used primarily SRT and some DdRT. The 8mm OP is on my lanyard and I use it fully loaded in SRT mode quite a bit so my trust level is quite high for these eyes. I kind of distrust the machine sewn eyes now ;-) Not really but I don't feel any more confident when using them.
-AJ
 
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moss said:
Here's a good thread where I posted everything I know to-date with links to photos etc.
Sewn eye documentation

Read both pages and click on the links to various photos, I'm waxing my own thread with beeswax, using the same size thread 75 lb. strength for 11mm and 10mm eyes, using the 45 lb. strength polyester thread that comes with the Speedy Stitcher for 8mm eyes.

I've just about worn out out a 10mm OP sewn eye cord, an 8mm OP sewn eye cord and it's getting to be time to retire my 150' Tachyon with a sewn eye on one end. I will have all these pull tested on retirement. I couldn't bear to pull test them new since I knew they were quite a bit stronger than my previous generation of sewn eyes (pre-compressed, stronger thread, better technique) and I put considerable effort into making them.

As I suspected they would, the eyes very much outlasted the cordage, no changes in the stitching or eyes. They look and feel same as the day they were sewn, the hitch cords were used primarily SRT and some DdRT. The 8mm OP is on my lanyard and I use it fully loaded in SRT mode quite a bit so my trust level is quite high for these eyes. I kind of distrust the machine sewn eyes now ;-) Not really but I don't feel any more confident when using them.
-AJ
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I just made a sewn eye splice in some Kernmaster for a lanyard, and a sewn E2E hitch cord out of HRC. It seemed appropriate to use the polyester thread for the Kernmaster, but I used Spectra for the HRC, because that cord is made with high modulus fiber. Do you think that's a good approach, or would you use polyester thread for all of your sewn eye splices?
 
dogwood said:
I just made a sewn eye splice in some Kernmaster for a lanyard, and a sewn E2E hitch cord out of HRC. It seemed appropriate to use the polyester thread for the Kernmaster, but I used Spectra for the HRC, because that cord is made with high modulus fiber. Do you think that's a good approach, or would you use polyester thread for all of your sewn eye splices?
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spectra has a real low melting point. i personally don't like it for exterior purposes. better for cores IMHO.

"Spectra:
Spectra is a very high molecular density form of polyethylene - the same thing used to make grocery bags, six-pack carriers and milk jugs. The manufacturing process aligns the molecules, which vastly increases the strength of the material. It is twice as strong as hardened steel (per unit area) and one-tenth the density. Spectra has several difficult issues. The melting point is very low, 147 °C or 297 °F, not much warmer than boiling water. The material is unbelievably slippery, which makes it difficult for manufacturers to form into a workable rope. And, while the modulus of the fibers is comparable to steel, they slowly elongate under a continuous load. This process is called "creep." It is mostly irrelevant to climbers, but annoying to sailors. Spectra/Nylon is also known as Dyneema (a trade name of Beal Ropes) in Europe."

the above is from: http://caves.org/section/vertical/nh/49/cthsc/cthsc.html
 
I'm not too worried about the lower melting point since the stitching is not subject to rope contact/friction if you protect the stitched area with shrink tubing. I haven't found any downside to polyester thread so I'm continuing to use it.
 
moss said:
Do you mean is there a reason I wouldn't use an alternative to polyester (or nylon thread which I also use)?
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Yes. Why not use something with a higher melting point? Lock stitching a spliced eye is one thing because the stitches are just a back up to an already strong splice but with stitched eyes the stitches are all you got. Is there a fiber compatability issue?

Also, you mentioned heat shrink. Don't you think the heat from that could begin to break down the structure of the poly?
 
TreeLogic said:
Yes. Why not use something with a higher melting point? Lock stitching a spliced eye is one thing because the stitches are just a back up to an already strong splice but with stitched eyes the stitches are all you got. Is there a fiber compatability issue?

Also, you mentioned heat shrink. Don't you think the heat from that could begin to break down the structure of the poly?
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Interesting point. The commonly used polyolefin tubing shrinks at about 230 degrees F. The melting point of Spectra is given at about 300 degrees. Apparently it is important to be careful about using the heat gun when installing over Spectra thread. I used Spectra to sew the E2E hitch in HRC. I then wrapped it tightly with some special stretchy silicone tape ( because I happened to have it on hand.) Then I put heat shrink over that. It seems to me now that polyester/nylon is probably the way to go.
 
This is from wikipedia. It says basically that the melting point is between 266 and 277 F but that it's not advisable to use at temps between 176 to 212 F because it can become brittle.

"The weak bonding between olefin molecules allows local thermal excitations to disrupt the crystalline order of a given chain piece-by-piece, giving it much poorer heat resistance than other high-strength fibers. Its melting point is around 130 to 136 °C (266 to 277 °F),[6] and, according to DSM, it is not advisable to use UHMWPE fibers at temperatures exceeding 80 to 100 °C (176 to 212 °F) for long periods of time. It becomes brittle at temperatures below −150 °C (−240 °F).
 
I suppose that's an argument not to use Spectra thread, at least if you're going to protect the stitching with shrink tube. My shrink tubed polyester stitching tested very well so apparently I'm not heat damaging the thread.
 
I hear ya Moss. Like I said, if you've tested it successfully, and it tested well, then I'm all for it. My only other question is, what are the other options for thread and why is spectra so favorable? Is it less expensive, does it match well with more fibers, or is it just ease of use? Is spectra what most of the production machines use on stitched eyes?

My apologies, that's more than one question.

BTW, I only ask you because you've researched this already and have stitched a lot of eyes by hand, amazingly well I might say. Thank you for your knowledge sir. :)
 
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