I calculated breaking strength for 8 inches of V-92 polyester at around 1000 lbs. Is this enough for climbing? Many people say you need 22kN or around 4000 lbs. I like to use a 10:1 safety factor, so for me, I would like my stuff to break at 1800 lbs of force or preferably more. See, Kevlar falls into the category of preferably more with the same number of stitches as polyester or nylon. I only started sewing with V-92 thread but my experience tells me that I could probably not get V-138 thread to feed through a cast iron home machine or I would use that. I think I will try V-138 at some point but V-92 worked great in my Morse sewing machine. If it didn't, I would have some spools of thread I could not use without buying an industrial machine.
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- Thread starter skell
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Yea I think that is a reasonable calculation if your box stitch has about 8 inches which is probably average. But the saddles I have made (and all commercials saddles) have at minimum 2 box stitches at the webbing joint overlap. I also add one on each of the four corners, as well as contiguous stitching around the edges (as in commercial models). Would this not increase the theoretical load to multiple thousands of pounds? 5,000 pounds is an average threshold for tree stand harnesses and climbing gear (which are OSHA approved to be safe) and a 6 foot fall by a 220 pound human can generate roughly the same amount of total force. This is sufficient to cause serious injury to organs and spinal tissues. If you generate 5,000 pounds of force, you have free fallen more than 6 feet while wearing a saddle, at that point kevlar thread is the last thing I would be concerned about. The Tethrd TMA testing video shows many 300 pound dummy drops from 6 feet of height in a mantis, which is a polyester thread stitched saddle
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Here are some stitches from the saddle I am currently sewing (my first). If these threads were all Kevlar I calculated it should break at 17,550 lbs. If all polyester half of that or around 8,500 lbs. These are about half polyester and half Kevlar so it should break around 12,000 lbs. I know we don't always have a 4 inch wide strap to sew, sometimes only 1 inch so the Kevlar can get more strength from fewer stitches. I think I already admitted I don't need Kevlar but why not go with the best. Many people do.
The second photo shows the backside of my strengthening stitches. I used a different machine than before and had difficulty getting the top tension high enough. I was maxed out on top tension so I lowered bobbin tension and the last line came out OK. I thought about ripping out the looped stitches but as you reminded me, I have more than enough strength even without them unless I put on a lot of weight.
The second photo shows the backside of my strengthening stitches. I used a different machine than before and had difficulty getting the top tension high enough. I was maxed out on top tension so I lowered bobbin tension and the last line came out OK. I thought about ripping out the looped stitches but as you reminded me, I have more than enough strength even without them unless I put on a lot of weight.
Sziggy2.0
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I dont see any picture of your stitches. Am I missing something? Only showing on taptatalk?Here are some stitches from the saddle I am currently sewing (my first). If these threads were all Kevlar I calculated it should break at 17,550 lbs. If all polyester half of that or around 8,500 lbs. These are about half polyester and half Kevlar so it should break around 12,000 lbs. I know we don't always have a 4 inch wide strap to sew, sometimes only 1 inch so the Kevlar can get more strength from fewer stitches. I think I already admitted I don't need Kevlar but why not go with the best. Many people do.
The second photo shows the backside of my strengthening stitches. I used a different machine than before and had difficulty getting the top tension high enough. I was maxed out on top tension so I lowered bobbin tension and the last line came out OK. I thought about ripping out the looped stitches but as you reminded me, I have more than enough strength even without them unless I put on a lot of weight.
I am using a computer. I don't use taptatalk.
I started a new thread about my saddle build here but was asked a few questions here so I replied.
My First Yellow Jacket (tm) Saddle Build *** Complete 1 lb 7 oz
Edit: People have asked me what I was going to name it and then I thought of a name. It is "The Yellow Jacket(tm) Saddle". Good enough. :D Today was the first time I took something that wasn't a saddle and made it into a saddle. I have been practicing with my sewing machines to good effect...
saddlehunter.com
I've been trying to find a bayonet style LED bulb for Singer sewing machines to reduce the heat load while sewing, for summertime use, and everytime I burn my hand on a hot bulb. The Dritz bulb, sold at Joann's fabric has a shoulder which prevents it from going into the socket far enough. With a 60% off one item coupon, this bulb sells for $4. I figured the metal could just be swaged so it fits. I have a PEX crimper which I used at the smallest opening to crush the bulb down. I have done two bulbs, working around swaging a bit at a time and they fit and still light.
You get that thing working yet? On all my vintage home sewing machines, I found Remoil works great to free up the dried oil then Dritz zoom spout sewing machine oil once the parts are free (Walmart). Sometimes an overnight soak is needed to loosen them.
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Nah man I’ve been dragging. Thanks for cleaning tip.
I am chomping at the bit to get an industrial machine but my wife might be mad if I did. I may have to clear the front porch and sew outside if I did.
I have to re-donate some home machines back to the thrift store. There are a few I tested and found wanting and could get rid of now. Others, I still have to test. Getting antique sewing machines working and sewing is one of the cheapest hobbies I tried, with an average cost of $20 per machine. I spent nearly as much on sewing supplies at Joann's fabrics as on sewing machines. The thrift store can be deadly for space management.
sdoyle1
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I hear you. As of two months ago I owned zero sewing machines. I now have 2 whites and one Kenmore home machines. I also bought a serger and just picked up an industrial machine. Need to get rid of two of the home machines.
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Yes. Two months ago I had one which had been sitting in the basement for 20 years, unused. Now I have 16. I am a sucker for deals. The thrift store has a monthly 50% off sale and I couldn't resist. One nice machine, I got for $6.50, many others for $12.50. The money goes to charity so that is another disadvantage to me running out of space. They are closed until March 28th due to Coronavirus or I could be in real trouble.
Going to pick up a free sewing machine today. I have the disease bad but financially it is nothing. I think I can cut my inventory in half by donating them back to the thrift store. I was only renting them. Yeah, that's my story.
sdoyle1
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Yes. Two months ago I had one which had been sitting in the basement for 20 years, unused. Now I have 16. I am a sucker for deals. The thrift store has a monthly 50% off sale and I couldn't resist. One nice machine, I got for $6.50, many others for $12.50. The money goes to charity so that is another disadvantage to me running out of space. They are closed until March 28th due to Coronavirus or I could be in real trouble.
Yeah. You got me beat. I slightly overpaid for the first two. They were worth it to me at the time. Since then I’ve come to realize there’s not a lot of value in them. The third one I got was almost identical to the second so I figured it was good for parts if needed. It was also free and works great. Lady said she tried to use it and needle hit something and broke and she decided sewing wasn’t for her. Pretty sure she was trying to use a zigzag stitch with a straight stitch presser foot.
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NYSFreezerMeat
Member
Sew, it's taken a few days to read the history within this lengthy forum. I'm excited to make my first attempt at some small projects with a quality thread injector. The Speedy Stitcher did a good enough job in the past, but I want to be more efficient with the time I have available. I've gained access to a Necchi model 3101FA (known as the mother-in-law's machine) and am just awaiting some additional materials. No plans for fabricating my own DIY Saddle, but I'm hoping to take care of some basic items before expanding. First up is a new HYS Strap, and some dump pouches. After that, I've begun an external frame pack rebuild and plan on some improved reinforcement with webbing for better weight distribution and support. Thanks to everyone that's contributed to this discussion, as the links to videos and additional resources made it an easy decision to attempt something new. It doesn' hurt that everyone keeps talking about cheap this hobby can be when compared to the hobby it's supporting. I can't remember the last time I spent less than $50 on any single hunting purchase.
My thoughts on Kevlar thread.
Kevlar is tackier than polyester. For this reason, stitches are harder to pull tight due to more friction between material and thread. Some of my domestic sewing machines could not pull the stitches tight. Polyester being slicker, having less friction, the stitches pull tighter easier and the same machines had no trouble. While cutting the polyester thread, one snip with scissors and it was cut. With Kevlar, I often went snip and the thread was cut halfway and I sometimes had to move it deeper into the scissor to cut it. Thinking about this, it makes sense since it is difficult for bullets to sever Kevlar when used in bulletproof vests. I still like the 2X strength of Kevlar over polyester. I was thinking of trying V-138 polyester but if I remember correctly the breaking strength is 23 lbs as compared to 30 lbs for V-92 Kevlar. The cost of Kevlar seems to be 6X that of the equivalent size polyester. If I am sewing a few saddles to support my weight I don't think 6X the cost is excessive.
Kevlar is tackier than polyester. For this reason, stitches are harder to pull tight due to more friction between material and thread. Some of my domestic sewing machines could not pull the stitches tight. Polyester being slicker, having less friction, the stitches pull tighter easier and the same machines had no trouble. While cutting the polyester thread, one snip with scissors and it was cut. With Kevlar, I often went snip and the thread was cut halfway and I sometimes had to move it deeper into the scissor to cut it. Thinking about this, it makes sense since it is difficult for bullets to sever Kevlar when used in bulletproof vests. I still like the 2X strength of Kevlar over polyester. I was thinking of trying V-138 polyester but if I remember correctly the breaking strength is 23 lbs as compared to 30 lbs for V-92 Kevlar. The cost of Kevlar seems to be 6X that of the equivalent size polyester. If I am sewing a few saddles to support my weight I don't think 6X the cost is excessive.
sdoyle1
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I could be wrong but I’d say unless you have an industrial machine you’ll likely not be able to run 138 thread. I’m running 138 in my industrial machine and you need a 20-22 needle. I’ve got larger m-class bobbins and still ran through about 4 bobbins on my phantom clone. You certainly won’t get much thread on a home machine bobbin. If you’ve got an industrial machine then I’d say go for it with 138 thread.
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I think V-138 polyester should work, but why? The V-92 Kevlar has a higher breaking strength than V-138 polyester..
Squirrels
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Mu juki 8700H will run 138 but I usually always go one needle size up so I run it through a 23. The 8700H doesn't use M class bobbins and that the one thing I dislike about running 138 on that machine. It eats bobbin thread like crazy.
sdoyle1
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I’ve never tried it before but I read where someone did and couldn’t get it to run right. I believe they said it was to inconsistent in diameter.
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