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FrogNog

Some sewing machine generic questions

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Background: I have sewn a lot of denim over the years using "home" sewing machines. Always single-needle, and I never used any attachments. I've also done an amount I would call "experimental" in serging and sewing with F-111. So I can sew, but I basically have zero experience with industrial machines or skydiving sewing.

I did some forum searching and got some answers, so now I'm driving into areas that I didn't find in the searches. Doubtless I could get some of this info elsewhere, and I will have to consult a number of other sources to learn in this direction, but in learning every answer helps.

Questions:

* What makes a good canopy sewing machine good? It's obviously not the ability to drive a big needle through a lot of heavy fabric. Is it how well and the technique by which it feeds thin, slippery fabric? Is it how far forward the feed grippers are, making it easy to start work on light material at precise locations? Is it a large throat to give lots of working space?

* Zig-zag vs. bar-tacker: I assume one use of a zigzag-capable machine is imitating a bar-tack, and I assume that in some situations a bar-tack machine is superior for speed, ease of use, quality, and appearance. Ignoring speed, ease, and appearance, does a bar-tack machine always produce a superior quality bar-tack than using a zig-zag? Are there some bar-tacks for which there are drawbacks to using a bar-tack machine (other than the drawbacks of having to have one more machine) such as odd sizes?

* Other than ersatz bar-tacks, what is zig-zag used for in skydiving? I think I've seen it in the thick reinforcement tapes in the nose of my Sabre2, but I can't remember anywhere else - and I might be wrong about even that.

* Is there such a thing as a Singer 31-15 that doesn't look old enough to have sewn the thirteenth star on Old Glory? I hear the 31-15 is a good straight-stitch machine by some method of accounting; what's so good about it? Is it that it gets most basic jobs done well for a good price? (And, presumably, stops any stray bullets headed your direction without needing to be retimed afterward?) Does it feed well? (Does it feed automatically at all? I thought I saw one for sale that did no feeding. :S) Are there alternate-brand versions that are newer and/or better for similar money, or a little more?

* Is a walking foot good, bad, or "depends on what you're doing"?

* Binding tape folders: my guess is there are two ways to attach them: the right way (bolting) and the crappy way (tape), and some machines will allow folders to bolt to them. I further guess that different brands and even models accept different folders, and that folders come in unexpectedly large price ranges, and therefore that you should actually know which folder you want to use before you buy a machine on which you will use it. Can anyone tell me I'm being way too paranoid about binding tape folders?

* Double-need work: besides binding tape and some canopy seams, where is double-needle stitching usually used? (I've always gotten away with single-needle stitching in my denim work - even on lap folds, where I sew three times to get a decent two-row stitch.) For someone starting out who wants to do both single- and double-needle stitching, would it be smart or not to get a machine that can do true double-needle stitching and use it as a single-needle machine most of the time? (I'm guessing that when starting out, I might do so little double-stitch sewing that I'll be permitted to use that machine in my local loft by the time it's an issue.)

* Back to tape binding: is this ever done, and can it be done, on a single-needle machine?

-=-=-=-=-
Pull.

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I'm sorry to read this. While this thread will never have the appeal of "So you want to be a rigger," I think FrogNog asked questions many of us would like answers to. I really liked your excellent posts on binding inside and outside corners, and that leads me to believe your PM response to this query is well-written, authoritative, and informative. Can I convince you to post your PM's contents?

Thanks,
Mark

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I'm sorry to read this. While this thread will never have the appeal of "So you want to be a rigger," I think FrogNog asked questions many of us would like answers to. I really liked your excellent posts on binding inside and outside corners, and that leads me to believe your PM response to this query is well-written, authoritative, and informative. Can I convince you to post your PM's contents?

Thanks,
Mark



I agree. Kevin, you have the knowledge and the skill. Share it please.

Sparky
My idea of a fair fight is clubbing baby seals

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Kevin, you have the knowledge and the skill.



Not having any rigging understanding, I'll have to trust you on that one, but I can add that he has a rarer quality: the ability to explain that knowledge.



And that is a skill that harder to learn than the rigging.

Sparky
My idea of a fair fight is clubbing baby seals

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thanks guys but I think my head just popped from getting so big. I actually didn't send him anything but my phone number because I realized that I would be typing all night to respond to all of his questions. I'll work on it and post my opinions in a day or so.
K

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* What makes a good canopy sewing machine good? It's obviously not the ability to drive a big needle through a lot of heavy fabric. Is it how well and the technique by which it feeds thin, slippery fabric? Is it how far forward the feed grippers are, making it easy to start work on light material at precise locations? Is it a large throat to give lots of working space?

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Size 16 or 18 needles are plenty strong enough to punch through canopy fabric (F-111 or zero porosity) and will feed E-thread (commercial size 69) all day.

Forget about depending upon feed dogs to feed canopy fabric through a machine. Canopy fabric is too thin for most feed dogs to get a good grip, ergo, you have to hand feed most of the time. By hand feeding, I mean grabbing the fabric just behind the presser food with your left hand and 8 inches in front with your right hand. As you press on the pedal, your hands feed the fabric under the needle.
Patience, this is a subtle skill that takes a few miles to master.
The other reason that you have to hand feed canopy fabric is that machine tension will try to "scrunch up" the thread and your hands have to hold the fabric at its original length to prevent shrinkage.

You can start sewing canopies on a heavy-duty home sewing machine. Heck! I sewed two kit canopies on a Pfaff 230.

The best text book in canopy sewing was published by Lone Star/Para-Kit in the late 1980s. Unfortunately it is long out of print. I have a copy, but will not part with it for love or money.

A large throat only makes a difference when repairing huge canopies. 99% of canopy production sewing is done on standard-throat sewing machines.

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* Other than ersatz bar-tacks, what is zig-zag used for in skydiving? I think I've seen it in the thick reinforcement tapes in the nose of my Sabre2, but I can't remember anywhere else - and I might be wrong about even that.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Ziz-zag is often used to reinforce stitching in the corners of containers and high stress points. Single-throw (304) is the most common zig-zag stitch in containers, but really high stress points - like where lateral straps enter the backpad are sewn with double-throw (308) zig-zag.
Multiple layers of container fabric (i.e. 1000 denier Cordura) can get so thick that you risk breaking needles. Breaking a needle half-way through a bar-tack is your worst nightmare!!!!
If you are going to break needles, at least do it slowly ... with a zig-zag.
Hee!
Hee!

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* Binding tape folders: my guess is there are two ways to attach them: the right way (bolting) and the crappy way (tape), and some machines will allow folders to bolt to them. I further guess that different brands and even models accept different folders, and that folders come in unexpectedly large price ranges, and therefore that you should actually know which folder you want to use before you buy a machine on which you will use it. Can anyone tell me I'm being way too paranoid about binding tape folders?

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Sew a few miles on a professional binder before spending any money on your own.
Binders range in price from inexpensive (see Para-Gear) to the ^%$#@! expensive (US$300+) folders from Atlanta Attachments.
To their credit, Para-Gear folders work great on thin materials like sliders, d-bags and log book covers, but when you start sewing thick materials (i.e. container stiffeners) only the very best (from Atlanta Attachments) will hold everything in alignment.

You should bind a few miles of light weight stuff before attempting to bind thick stuff.

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* Back to tape binding: is this ever done, and can it be done, on a single-needle machine?



>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Every day!
Just look closely at all the single-needle binding on cheap camera cases, cell phone cases, etc.
You can even bind parachute components with a single-needle machine, just plan on sewing a second pass a few millimeters over.

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* Double-need work: besides binding tape and some canopy seams, where is double-needle stitching usually used? (I've always gotten away with single-needle stitching in my denim work - even on lap folds, where I sew three times to get a decent two-row stitch.) For someone starting out who wants to do both single- and double-needle stitching, would it be smart or not to get a machine that can do true double-needle stitching and use it as a single-needle machine most of the time? (I'm guessing that when starting out, I might do so little double-stitch sewing that I'll be permitted to use that machine in my local loft by the time it's an issue.)

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Possible, but not worth the headache.
Double-needle machines are so fussy to adjust that you are better off adjusting it once and leaving it.
Buy a second machine for all you single-needle sewing.

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This is my 0.02.

The one machine that will do 'em all is a Singer 20U or a clone of it.

It's not too fast so it does not take too much time to get used it.

Its single stitch ain't that bad and you can mimic the bartack.

It will go through thicker stuff and it loves type E (69).

Next would be a double needle and then when you get your Master ticket a harness machine (7-33).

I have a 20U and do everything with it but harnesses, of course. With patient you can bind tape too, a bit of a PITA but it's doable.

I bartack lines of all types with it: from thin Vectran to 900 LB Dacron and the quality is really good sometimes better then some real bartack I'v seen.
Again it's not as easy to do as with a true bartack machine but doable.

One day I'll buy a double and a 7-33...

If I were in you that's what I would get a 20U.

Send me a PM so I can give you a link.
Memento Audere Semper

903

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I was originally recommended a Singer 20U as my first machine by someone knowledgeable. (He sews canopies every once in awhile and brought airlocks to ram-airs, or something crazy like that. ;))

When I called around to see who had one for sale, I got a sales guy who knew a little about clients who used machines for various skydiving rigging tasks, and he seemed to think the 20U didn't have anything going for it - its only recommendation being that it could do zig-zag and straight, but the zig-zag ability would make it a lighter-duty machine than a comparable straight-stitch-only and of course he didn't know anywhere zig-zag was used other than bartacks - and he didn't know bartacks were used other than canopy creation or repair, where he figured the 20U's modest speed would be a grave hindrance.

Hearing one of y'all say you actually use a Singer 20U and do a lot of stuff on it has reinforced my faith in the original recommendation. (Which, based on the person who gave it to me, I feel sort of ashamed I questioned. But a second rigger's opinion isn't a bad thing.)

-=-=-=-=-
Pull.

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Sounds like your local salesman was worse than clueless!

I have sewn many miles on Singer 20U machines.Every loft should have one, if only for canopy repairs.
Their only limitation is difficulty penetrating multiple layers of thick container materials.

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