Ellpea

I'm trying to help a friend who would like to sew hems on knit garments with a double needle.

Confession up front: hers is not an antique machine, but it may qualify as vintage: It's an "Elnita," and is Very Heavy -- lots of metal inside.

She had a 4.mm, size 11 needle for stretch fabric. The stitches on the top of the fabric were very good and seem secure, but they seemed to miss something occasionally on the bottom thread.

According to her manual it could be a needle size problem, and the 11 is pretty small. We also tried adjusting tension and stitch length. Since the problem was underneath, we thought the problem must be top tension, but going all the way through all choices still did not eliminate the problem (although certain settings had better results than others).

I have some photos to post, although I'm not able to indicate which sections had which adjustments.

My main question probably is: should the bobbin thread look like it is pulled completely to one side? I would expect it to have an even zig zag appearance, but don't really know, having never sewed with a double needle.

I promised her I would post photos, and that people here were very smart and could probably help!

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In the areas where we've at least managed to get a consistent stitch, even if it is not quite even as a zig zag on the back, should we call that good? Or?

manicmike

Your expectation is correct. It *should* look like a nice even zig-zag. I'm going on my experience of double needles on actual (50+ YO) vintage machines though. Maybe modern or stretch make some difference but it still doesn't make any sense for it to be skewed.

I'd think the needles must have different upper thread tensions to exhibit this problem. Since both threads are the same weight and go through the same tension discs, the culprit is probably the tension mechanism. To check, remove the threads from just the needles (so you don't bend or break them when you pull), put the presser down (to engage the tension) and pull the end of each thread in turn. One should be obviously stiffer. You will have one that's either too loose or too tight. Can't tell you which, but I suspect tight (if one was very loose, the lower stitch might include loops). Either way, if one is tighter I'd suspect dirt on a tension disc. The solution is to disassemble, clean then reassemble.

Perform the thread pull test again and you should find that both have the same tension. Thread it up and do a test sew.

I'm really making a lot of assumptions there, but the diagnosis is right you'll want to take photos during disassembly. Very easy to forget how it goes together.

Jeanette Frantz

I don't know whether this has anything to do with it, it having been many years since I sewed on double knit. It was my understanding that polyester doubleknits respond best to a ballpoint needle. I'm probably not phrasing that correctly, but I had a terrible time sewing on my machine when I first started sewing on doubleknits, I haven't sewn on any knits in years! LOL!

Jeanette

Macybaby

Since it's also predominantly skipping one needle, it could be the timing needs to be adjusted so that it's lining up better with both needles.

How does the machine sew with one needle and the widest zigzag? Try it with knit and without to see if it also skips stitches that way. Knits can be a monster on some machines. Ball point needles help, as they push the threads aside so the needle can pass between them. Sharp needles may penetrate the knit thread, and cause it to hold the thread too close to the needle so it does not loop slightly and the hook can't grab it.

quiltmouse

I use a double needle to hem knitted things fairly often. I sew exclusively on a Singer 403.

Manicmike has good technical information in his post.

Here are some more basic points. You are correctly using two ball point (for knit) needles. When you thread the machine, thread each thread separately, do not pull them through the tension at the same time. If your tension has double tension rings, put the two threads in two different rings. I think your needle is too small. It looks like you are testing the stitch on a cut off t-shirt hem. (Great idea!) If the fabric is similar in weight, try bigger needles, maybe 14? I get skipped stitches when the needle is too small.

Also, see how your fabric is kind of stretched, compared to the commercial hem in your sample? That stretch is happening because of the pull of the presser foot against the feed dogs. What I do on that is cut strips of notebook paper, and "protect" my fabric from the pull of the foot. So your layers are, up from the machine bed, fabric, paper, foot. You just position the paper immediately to the left of where the left needle is entering the fabric. the presser foot just glides along the paper, the feed dogs move the fabric, the fabric slides under the paper.

On a single needle, for knits, I use the single hole soleplate, that helps with the drag, also.

quiltedsunshine

We have a woman who teaches a knit maxi skirt class on a regular basis, and they hem it with a double needle. The trick is to adjust the needle bar position a little to one side or the other (don't know if your Elnita has that capability). Try both directions and see what happens. Adjusting the needle bar position, actually changes the timing just enough to make the double needle work.

It's hard to find a ball point double needle. You'll be alright with a 'universal."

Also, seperate the two threads by putting one in the lowest thread guide, and leaving the other out. That way, they don't twist together before they get to the needle.

barny

I think you are using too small needle. I sew on double knit[but not double needle], and it does this on a small needle. Use 14 or 16. Other than that, I don't know what to tell you.

manicmike

I didn't even see that (duhhh), but Cathy's absolutely right, there now appears to be two problems. I've also had horrible trouble sewing knits, and even with a ball point needle it can easily skip stitches. You need to have the right size needles for the thread, ball point needle and the right width and tensions set. It really takes a lot of knowledge to get a good stitch. I've been thinking about this quite a bit (especially when I can't get it right), but if you want to sew a lot of different fabrics you need to have a vast knowledge of how machines and needles work with the fabrics.

I doubt this is a timing issue, but I could be wrong.

Even when it isn't skipping stitches there isn't a zig-zag pattern, so I'm still thinking there's a problem with the upper tension discs.

I'd solve the skipped stitches issue first though, then address the skewed thread tension. Skipped stitches can be obvious, but who looks underneath and checks for a nice, even ZZ?

Ellpea

Thank you everyone for weighing in on this! B. bought a larger needle on her way home, and I've asked her to try the dollar bill trick on her tension (for now), and leave the second thread out of the final thread guide. Will let you know what happens!

path49

I sew a lot of twin needle hems on knits. I loosen the upper tension slightly & use a Schmetz stretch double needle. A stretch (not ballpoint...stretch) needle on knits will stop the skipped stitches. I usually use a size 75 / 4 and never have a problem o nearly any weight knit. They're not hard to find....Hancock's has them or you can buy online.

Paper under the fabric is a great tip for the rippling & sometimes a walking foot will help. So will lightening the presser foot pressure.

Nancy Zieman recommends NOT separating the threads til you get to the thread guides right above the needle....so I usually run both threads thru the same tension discs & separate them at the guides above the needles.

I do my hemming on a vintage Kenmore.