Ajax

Heavy duty sewing machine

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19 hours ago, estarzinger said:

And . . . yea I took down all my web testing material years ago . . . . . I had too many people misunderstanding and/or misusing the information - made me nervous, and a few of them got angry at me when I tried to correct them (including a couple of magazines that misrepresented the work/results). It just ended up not being 'fun' for me to have the material posted. I mostly 'play' with people doing heavy (industrial) lifting today.

Sinceriously. Many respect all of your efforts.

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16 hours ago, estarzinger said:

^^ Thanks . . . yea. I was wondering/guessing that you could program it to make your own custom stitch pattern, but that you needed to go quite far down the rabbit hole to figure out how.

I presume it can use v92 thread?

She ran v69 thru it at the shop and they said it could run a heavier upholstery thread but I don't remember what it was. The v69 worked easily if that helps. 

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On 2/15/2021 at 12:38 PM, estarzinger said:

And . . . yea I took down all my web testing material years ago . . . . . I had too many people misunderstanding and/or misusing the information - made me nervous, and a few of them got angry at me when I tried to correct them (including a couple of magazines that misrepresented the work/results). It just ended up not being 'fun' for me to have the material posted. I mostly 'play' with people doing heavy (industrial) lifting today.

Well, then I am sorry that I published your for me not forgotten results. They are still on the machine that remember everything on the internet. I shall try not to do it again. But you reference one or two government reports on sewing with parachute webbing, and I have had a hard time finding these reports. Do you eventually know where to find them.

When you use the zig zag mechanism on a normal sewing machine, it is normally the same kind also used for bottonholes. It can be hard to control exactly how many stitches you get in the bar tag unless you actually count the number manually while you do the stitching. With the embroidery machines and other machines that control the fabrics XY-position, you got control of this matter automatically. However I guess that the domestic embroidery machines may not have the punching power to stitch heavy webbing.

I have been thinking about the rope eye or webbing eye problem. You almost always get the problem near the first stitches transferring some of the load. So perhaps you could use stitching alone (no transfer to other webbing or rope) for the first inch to improve the strength of the rope or webbing before you start to transfer the forces away with the stitches.

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44 minutes ago, Gymnast said:

you reference one or two government reports on sewing with parachute webbing, and I have had a hard time finding these reports. Do you eventually know where to find them.

They were on the net as pdf's.  Google should be able to find them.  Basically . . . .  there were two use cases (a) end loops (loop sewn into the end of a piece of webbing) where bar tacks were the answer and (b) Slings (webbing is sewn end to end to form a loop) where there seemed to be some disagreement (or rather perhaps two different but both valid answers) between long multiple V patterns and bar tacks.  My testing suggested the V pattern was (very slightly) preferred if you were sewing the two ends together also to the 'body' of the sling (so you had 3 layers) while bar tacks were preferred if you were sewing the two ends together not to the body.  The parachute documents I had did not dive down to that level of application detail.

I have been involved in one 'modern' parachute application and very little webbing was used - was mostly spliced cord - web only used where we had a bend ratio problem we could not solve any other way.

 

Quote

The 'sling' is much preferred to the end loops.  You basically always see sling construction and not end loop construction in 'serious' applications. Even if what you really want is a long piece of webbing with 2 end loops (like on a jackline) - you just use lighter webbing and double it to make a long doubled sling (and you can sew down the 'body' to make it like one piece of webbing in the body if that is useful for the application). 

However I guess that the domestic embroidery machines may not have the punching power to stitch heavy webbing.

Polyester and dyneema webbing tends to be thickish, but actually not all that hard to punch thru.  Thread tension can be a bit tricky to get right, and if you get it wrong the strength of the join can go way down, but that is (usually) easily QAed by eye.

I have been thinking about the rope eye or webbing eye problem. You almost always get the problem near the first stitches transferring some of the load. So perhaps you could use stitching alone (no transfer to other webbing or rope) for the first inch to improve the strength of the rope or webbing before you start to transfer the forces away with the stitches.

Interesting idea . . . . I am a little skeptical :) but it would not be hard to try.  The 'sling construction' spreads the load out more evenly and minimizes the first stitch issue.

In recreational products, I think the climbers have their shit sorted out rather more thoroughly than most others (and most certainly more than in sailing).

 

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So today she ran some v92 thru the machine. It won't do the automatic threader but it worked. That's probably as big as you'd want to run through this machine.

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V92 is about as big as most home machines run-it’s the max limit for the Sailrite LSZ1 as well. The difference is the sailrite has a fairly large under foot clearance and is a walking foot machine.

I’ve been searching high and low for an industrial zig zig machine and have come up short....I would like to be able to run V-138 thread on occasion.

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Can I interrupt this thread for a shameless bit of gloating?? I just found this little beauty online, original Adler 267 walking foot straight stitch machine... the wife doesn't quite share my enthusiasm (but she has already tagged that it will sew leather and is expecting a new handbag....)

267.JPG

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2 hours ago, F18 Sailor said:

V92 the max limit for the Sailrite LSZ1 as well.

 

I know what the specs say . . . but have you tried V-138 . . . mine will run it with some adjustment . . but max v92 seems good for like 99% of stuff

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54 minutes ago, estarzinger said:

I know what the specs say . . . but have you tried V-138 . . . mine will run it with some adjustment . . but max v92 seems good for like 99% of stuff

I don’t have one so can’t say; to your point it probably will, given my White machine CAN run it (issue is not enough upper thread tension with the stock tensioner); this machine has the same internals as the Sailrite but lacks the power of the large fly wheel and I don’t have it mounted in an industrial table, both things that would make it much more useful for doing canvas and heavier duty work. To be fair, I think V-92 thread is just find for a lot of repair work or canvas projects.

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1 hour ago, F18 Sailor said:
2 hours ago, estarzinger said:

I know what the specs say . . . but have you tried V-138 . . . mine will run it with some adjustment . . but max v92 seems good for like 99% of stuff

I don’t have one so can’t say; to your point it probably will, given my White machine CAN run it (issue is not enough upper thread tension with the stock tensioner); this machine has the same internals as the Sailrite but lacks the power of the large fly wheel and I don’t have it mounted in an industrial table, both things that would make it much more useful for doing canvas and heavier duty work. To be fair, I think V-92 thread is just find for a lot of repair work or canvas projects.

I just ran some V-138 for the first time on my LSZ-1 and it worked fine with a #22 needle and the upper thread tension cranked up a couple of turns from the V-92 setting. 

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On 2/16/2021 at 11:14 PM, estarzinger said:

They were on the net as pdf's.  Google should be able to find them. 

Thank you for your reply, Evans.
I now got the test reports from US and one from UK regarding webbing for parachuters. But you got a figure with different patterns and a percentage of nominal strength. This figure seems to be from and old report, but I could be wrong. The figure text is: "10-19. Stitch patterns and their relative strength".

Yes, I agree, that the sling construction for loops is to be preferred.

I remember, that you distinguish the end to end joining problem to the single loop problem. I tend to think, that the end to end problem is like the loop problem twice. I argue like this: When you join end to end, you want to transfer the load from one webbing from 100 % to 0 % gradually along the stitch pattern. In the middle the transfer should be 50 %. In the loop case, you want to transfer the load from 100 % to 50 % along the stitch pattern. So it is the loop problem twice. Am I wrong?

I have been in a project for gymnasts, that needed just a bit of lifting help for some tumbling. For this shock cords were used and I needed loops on the ends. The loops were  made like this to cope with the differences in elongation:
100-140-220pct.thumb.jpg.1efb0800f438e977369710af6c3bd390.jpg

I think the elongations for ordinary rope is not that extreme, but you got the same problem.

I needed to make about 60 of these loops, and I contacted a shop with big JUKI sewing machines. He stitched a lot in leather for quality furniture and used Tex 270 thread for that. And I made a fixture to hold these shock cords in place for sewing zig zag. He first tried and said he could do it. But when he should make the 60 he backed out of project and said that his machines could not make it. I know it is very difficult in such rubber materials. It acts like stretch fabrics and the loop at the needle do not form, so it can be catched by the hook in the sewing machine. So it took me 3 days afterwards to do this manually.

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On 2/19/2021 at 5:09 PM, Gymnast said:

I tend to think, that the end to end problem is like the loop problem twice. I argue like this: When you join end to end, you want to transfer the load from one webbing from 100 % to 0 % gradually along the stitch pattern. In the middle the transfer should be 50 %. In the loop case, you want to transfer the load from 100 % to 50 % along the stitch pattern. So it is the loop problem twice. Am I wrong?
 

i tend to avoid theorizing because I was wrong and surprised so many times when I started getting actual test data.  But I believe when comparing an open sling (eg the middle and the join NOT sewn together) to two end loops -  the first order effect would be at the same total load, the highest loaded stitches will take (roughly) 1/4 the load with the sling vs with the two end loops - because the sewn section takes 1/2 load to start (as the other half of sling takes 1/2) and then the end to end joins loads two ends of the stitching while the end loop only loads one end.

There may (not sure) also be a (more complicated) favorable second order effect - inside the two ends first rows of stitching, and which could well depend on the specific stitching pattern - but some research would be needed to explore that. For instance, with an odd number of bar tacks, the bar at the dead center of the pattern should take even loading from both ends (while with even number of bars, all the bars are more side loaded).  Climbing slings seem to be generally built with odd number of tacks.  And it would seem (from test data) that a 'closed' sling (eg where the end to end is sewn 3 ply to the other side of the sling, may further spread the stitching load. 

I think I am basically agreeing with you . . but not sure . . and I am reaching here with quite limited data. Actually looking into it might reveal surprises.

IDK - while the details of the stitch loads would be interesting to understand in better detail, all we really need to know is "sling better than end loops" and 'bar tacks good' :)

-------------------------------------------------------------

I was happy to see the mars rover para deployment/landing go flawlessly - the whole deployment process was decently complicated and was a pretty highly engineered system, every fraction of a gram was critical.  The Mars team has always seemed pretty (exceptionally) solid. Technora and Ti in the bridle, riser, shrouds.

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Thank you Evans for sharing your thoughts. I have seen a lot of load test videos arrive on youtube. This one is climbing in threes, and made quite many: https://www.youtube.com/c/RichardMumford1/videos 

On 2/17/2021 at 5:04 AM, ordkhntr said:

So today she ran some v92 thru the machine. It won't do the automatic threader but it worked. That's probably as big as you'd want to run through this machine.

Interesting that this new machine is able to do this. Sometimes the problem will be to get sufficient thread tension on the needle thread. But I guess you could replace a tension spring there to a stronger spring if needed.

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Just scored this original Pfaff 130 with industrial motor and butcher block maple bench top. Purrs like a kitty.

 

thumbnail_IMG_4200.jpg

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9 hours ago, Gymnast said:

Thank you Evans for sharing your thoughts. I have seen a lot of load test videos arrive on youtube. This one is climbing in threes, and made quite many: https://www.youtube.com/c/RichardMumford1/videos 

Interesting that this new machine is able to do this. Sometimes the problem will be to get sufficient thread tension on the needle thread. But I guess you could replace a tension spring there to a stronger spring if needed.

There are a couple demo videos on youtube showing someone running layer upon layer of denim, then vinyl, then silk, one after another without adjusting tension or anything and the stitches come out looking perfect. We are going to try and replicate them this weekend. 

Also, once she sized up the needle she was able to use the automatic threader with the v92. Its quite a machine, but for the price it better be :) 

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@Irrational 14 Pfaff 130:

Madame apprenticed in a canvas shop with a P130 (and a 138). They had added springs to the pressor foot shaft; aggressive-toothed feed dogs (stock are knurled). Imma guessing yours may have that. If the clutch motor is painful to use, change out to a servo motor, Madame likey hers very much 

P130 is our aboard machine; canvas to silk. Helluva score!

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18 hours ago, ordkhntr said:

There are a couple demo videos on youtube showing someone running layer upon layer of denim, then vinyl, then silk, one after another without adjusting tension or anything and the stitches come out looking perfect. We are going to try and replicate them this weekend. 

Also, once she sized up the needle she was able to use the automatic threader with the v92. Its quite a machine, but for the price it better be :)

I think most machines can do many layers of denim etc. but it is the thread thickness that will show the difference. I guess you need about a size 19/120 needle for the V92 thread.
 

8 hours ago, Max Rockatansky said:

@Irrational 14 Pfaff 130:

Madame apprenticed in a canvas shop with a P130 (and a 138). They had added springs to the pressor foot shaft; aggressive-toothed feed dogs (stock are knurled). Imma guessing yours may have that. If the clutch motor is painful to use, change out to a servo motor, Madame likey hers very much 

P130 is our aboard machine; canvas to silk. Helluva score!

I have not tried the Pfaff 130, but I have noticed, that many sailors like them. I have seen one for sale for about 2 month in Denmark, and now the price dropped to about $30. I do not have space for more machines, so I wrote to the seller to contact the local sailors club. Hopefully now another sailor will be able to use it. The Pfaff 130 are quite often for sale here.

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