Here’s a little technical post today. I don’t write these often because I’m a beginner and almost everything can be found fairly easily on the Internet these days. Now and again though, I come across something that took me a while to find or didn’t quite answer all my issues and hopefully what I’ve done will be useful for others. Today it’s the turn of… hemming knits with a twin needle! Woah! Grab your Moscow Mule and take a seat!

The Issue aka Hemming Hell

Alright, so, in a nutshell, here was my problem. I had been using the twin needle to hem t-shirts and other knits, using many hints and tips I’d read in articles or books. The stitch seemed to work pretty well and looked okay, but, then, after just a few wears, the threads would snap. The first time I thought perhaps I was using the wrong type of thread on one of the spools or the incorrect width of needle, but it slowly happened to everything I had sewn. In addition, sometimes when I was sewing I could feel that one of the threads was a bit “tight” and was pulling a little, but couldn’t figure out what was wrong. Gah!

You’re looking a bit tense…

I’m going to talk about this by starting off with the last thing I tried, but the thing that has made, without a doubt, the biggest difference. It has given me the stretch I didn’t even really know I was missing at first and it was achieved by lowering the tension on the bobbin thread (lower).

I’m going to go through the rest of my set-up afterwards because I also think that it is important to follow a few other little rules, but this was the game-changer. Having said that, I really, REALLY, didn’t want to be mucking about with bobbin case screws every time I wanted to hem, so I actually bought a second, extremely cheap, bobbin case from Amazon for my Brother CS6000. I think was around $10 when I bought it, so I figured it was worth trying.

I marked the new one with a gold Sharpie to differentiate it from the original and then used a small screwdriver to loosen the screw (below) a full turn. I sewed a line of stitches and then loosened it another full turn, but didn’t notice a significant difference, so just left it there.

Now to show you some results. I had been tinkering around with this for a while and had already tested a few things. First, I want to show you how my twin needle stitch was often ending up. It looked absolutely fine on the front but did not look like a “zigzag” on the back, which is what you’re going for. It was pulled quite horizontal in some cases and a little looser in others (ignore the buttonhole!)

I read several good articles with various suggestions for twin needles in general. One or two suggested raising the upper needle tension to create the zigzag. I tried using the standard 4 and 5 as well as the tension level of 2 that I prefer for knits. Another suggestion was to lengthen the stitch length.

You can see that the higher tension and longer stitch on the two right lines does help a little but it’s definitely still not ideal. I noticed it also created a bit of the dreaded “tunneling” effect on the right side of the fabric as the tension got higher, which was not something I’d had too much of a problem with before. You can also see the results of just a little tug on the line of stitches at the left side here, compared to the first pic above. The thread just snaps. All in all, I figured the bobbin thread had to be too tight, if anything was up, and to go ahead and try adjusting that tension.

So here is another test I did, with side-by-sides. First, I tried the old bobbin and sewed at tension 4, length 2.5; tension 4, length 3.5; tension 5, Length 3.5; and finally tension 2, length 3.5. Now, you can see that the stitch already looks more like a zigzag on this cotton jersey fabric, and indeed, it was the one I had the best results on… before it snapped. However, there is quite bad tunneling on the first three lines with the higher tension, and when I drop it down to 2 again, the zigzag starts to waver. I have seen recommendations to add some tape or stabilizer behind the hem to avoid the tunneling, but I still felt there was another issue since the stitches still didn’t have much give, even if they did look more “correct”.

Now, I sewed 2 lines with the replaced, loosened bobbin. I used tension 2 and 3.5 length stitches and I think you can immediately see the difference. It looks like a proper zigzag, the tension looks much more balanced (you can’t see much pink upper thread) and, most importantly, I gave the fabric a good tug and it seemed very elastic. Woohoo! Success! I’ve since hemmed a few garments using this set-up and all seems good… so far.

Tips and tricks

It will come as no surprise that I recommend buying a second bobbin case if you are experiencing these issues too. It’s a lot cheaper than a coverstitch machine!! However, here are some other tips I picked up that are also useful:

1. A walking foot comes in very useful, and particularly when using slinkier knits. I always use one.
2. I use a stretch twin needle, because I thought that might be affecting the tension. In all honesty, the universal twin needle worked fine for me, but some people experience skipped stitches with it.
3. Slow down a little. This definitely does make a difference to both tunneling and general stitch quality for me.
4. Make sure you use polyester thread. My “second spool” was cotton one time and I didn’t notice. Snappity snap snap!
5. Different twin needle widths can increase/decrease the tunneling effect. Make sure you’re using the correct width for your fabric.

There are a ton of other tips to be found that may or may not help you. I would recommend checking out Moon Thirty’s guide as well as the tips on the Oliver + S blog, which include the suggestion to use woolly nylon in the bobbin. I haven’t tried this, but it would have been my last port of call if this experiment hadn’t worked. For me, the bobbin tension was the key, but it may not be for you. I wish you the best of luck in finding your solution and hope this helps a little! 🙂