Dense weaves · Nanotex

It’s not the thickness, it’s the density

…that makes a fabric appear “heavy duty” to your sewing machine. Let’s not count how many decades it took me to figure that one out! ๐Ÿ˜ณ

But first: what do I mean by “heavy duty”? Something that requires significant punching power to get through. Like saddle leather, sail canvas, military felted wool, but also many impregnated, foiled and coated materials, mackintosh cotton, denim, beach chair canvas – all of these sound quite “heavy duty”, and I’m sure you can add a few of your own. But how about this: fine Egyptian high-count cotton, silk taffeta or Oxford weave shirting, cotton or viscose? And some microfibre interlace knits? Not something I thought of as “heavy duty”, that’s for sure.

Turns out, the key is not in the thickness of the material but in its density, so dense high-count cotton, even lightweight, is just as difficult to punch through as impregnated raincoat canvas. On the other hand, thick but “loose” materials like soft fleece are easy to sew even by hand.

Lockstitch sewing machines are not particularly fussy about the density of the material they are sewing, except of course plastic-geared machines that just stop or break their gears – we are not talking about those. Overlockers, however, are much more sensitive to the density of the material – they require significantly different tensions or even refuse to sew some fabrics altogether. This is because when thread tension becomes too high for a particular overlocker, as needles and loopers bend under tension, they come too far away from each other and stitches get skipped. It is normal for needles and loopers to bend, the machine is built for it. The point is that the amount of bending must be within a certain small margin so that needles and loopers would still meet and form stitches. For the ins and outs of that, see two of my previos posts: the first post and the second post.

Heavy duty overlockers have “beefier” components and use thicker needles (or special hardened needles in industry). But these same beefy parts together with a strong feed don’t give good results on soft and light fabrics which just get chewed up. So you need both kinds of machines.

All these insights came from my attempts to sew what I thought to be rather lightweight summer viscose.

But it is rather densely woven in Oxford weave, so that it drapes beautifully and keeps shape a bit.

I tried using my fine overlocker on it, and although it almost managed, the stitch wasn’t great, I had to deviate a lot from the usual settings and some stitches were skipped. “Feels like the fabric is too heavy for it!”, I thought. Nah, can’t be – it’s only a summer dress! But still I decided to try my heavy duty overlocker. Perfect stitch on standard settings. Oh! ๐Ÿ˜ฏ

And then all my previous mis-adventures suddenly started making sense! I was not treating dense fabrics as heavy duty!

Dense mircofibre knits are even worse in this respect – they also stick to the needle. The same goes for foiled fabrics.

For example, dense “nanotex” interlock jersey would not get sewn properly, not even with special needles.

I had more skipped stitches than well-formed ones. And those machines had no trouble with triple layer denim, so clearly they possessed enough punching power.

The problem there was that that nanotex jersey was sticking to the needle and thread preventing them from forming a loop for the hook to catch. It wouldn’t have had such a devastating effect if the jersey was loose knit, but being dense sealed the fate of that sewing excercise. The solution was to use a vibrating shuttle machine with a different needle drive allowing it to overcome any sticking of fabric quite easily. See this post on how they do it.

I still don’t know how to sew such knits on modern machines. As for non-sticky dense fabrics, you would normally use a thicker needle. Except of course on fine fabrics like that Egyptian cotton or Oxford weave viscose. The solution there is simple, really: use needles with a sharp point.

Looking at the picture above (from Wikipedia), there are several sharp points: universal, jeans, microtex and leather, so which one to choose?

First of all, not leather: the leather point has a blade on it, so it will cut through the threads in your fabric. It’s for leather only. ๐Ÿ™‚ 

Jeans needles appear to have a slightly different shape from the universal needles. Schmetz jeans needles are also made of harder steel. But I found that jeans needles from many other makes are exactly the same as their universal ones – I looked under strong magnification. I think that since you cannot see the difference with a naked eye, many makes simply see it as an easy way of making money. ๐Ÿ˜ฆ I use thicker universal needles on denim without any problems.

Now we are left with universal and microtex. Microtex needles have an acute round point (SPI) also known as the “slim set point” (SSP), they are recommended for microfibre jersey and most delicate densely woven fabrics like silk (see this PDF from Schmetz). They feel sharp to your finger because the point is slim and penetrates the skin; but that slim point is also quite fragile and bends easily, so if you use these needles on high density fabric, they tend to go blunt very quickly and start punching big holes.

So which needles are best? Well, the most ordinary universal ones. ๐Ÿ˜ Use them with your dense fabrics – you can even try them on overlockers that take 15×1 needles. There’s a reason they are called “universal”… ๐Ÿ˜‰

Buy me a coffeeBuy me a coffee ๐Ÿ™‚

14 thoughts on “It’s not the thickness, it’s the density

  1. Great analysis. Thank you. I never really thought much about needles unless I knew I needed a heavier duty one for canvas or some such. I mostly see natural fabrics. Then I decided to try sewing knits. My test scrap sewed fine with a ballpoint, but when I tried a scrap if the actual fabric it was a no go. I think I just choose a picky fabric (which was fine, but dense) and had to have a specific size stretch needle.


    1. Yes, some fabrics are just evil. I find that “microtex” needles usually manage most jersey, even if it doesn’t look like microfibre. And sometimes – strangely – a universal needle works better. It’s not an exact science. ๐Ÿ˜‰


      1. I agree about evil fabric. I have a love/hate relationship with linen. It’s squirrely, especially small pieces with a lot of bias. I bet one of the biggest issues with needle choice these days has a lot to do with the myriad of fabric options, mixing of fibers and frequency of part of the mix being synthetic.


      2. You are probably right! Which is exactly why I use old long bobbin machines for straight stitch – they don’t have this problem. They sew every fabric – even the most evil of them – with the same universal needle if you like, and they never skip stitches. But of course as soon as I want a bit of zig-zag, I’m back to round bobbin and back to trouble. ๐Ÿ˜›


      3. Oh be careful – the VASM (Vintage and Antique Sewing Machines) virus is very catchy and there is no known cure! Once you’re in, you can’t escape! ๐Ÿ˜ฎ


      4. I know… I’ve been careful. I only have 5 machines (three vintage). Honestly, I love my old Kenmore enough – she’s very sturdy, fixable and sews at least 7 layers of double fill #10 duck – that I’ve resisted others. But you’ve got me thinking…

        Liked by 1 person

      5. I find that a lot of post-war machines do much better on heavy materials than on fine ones. They are powerful and dependable, and on thicker stuff round bobbin mechanisms work just fine. It’s when you attempt to sew something fine or slippery, that you often get in trouble. Jersey is very popular these days for example, but all our machines can offer for sewing it is zig-zag. No, “stretch stitch” is not suitable because it is too dense and makes holes in the material and stretches it out. And plain straight stitch rips to bits of course – it does not stretch with the fabric. But I get 60% stretch on plain straight stitch on a transverse shuttle machine without even trying – just reduce both tensions way down. Round bobbin machines can’t do that.


      6. I haven’t done too much sewing in knits, but I have been fairly disappointed with my stitching options. Don’t get me started on my overlick options. My machine is from the 80s (maybe). Brother has no record of the model and I have no manual. The thing has two stitch option levers. One blade is fixed and the other moves, but can’t be disengaged or widened/narrowed. It does the basics only.


      7. I have a similarly basic overlocker from 1970s (Juki for Janome) but mine works extremely well. It sews almost anything with 3 or 4 thread overlock. No differential feed but I never missed it! Never had fabric stretching out or gathering or anything. I now have two more Juki overlockers (branded AEG and Singer) – one for light materials, the other for heavy, and I use them for all that fancy stuff like rolled hems and woolly nylon edging that my basic overlocker can’t do.


      8. My only complaint is the lack of the differential feed and not being able to do things like rolled hems. Clearly I need another machine! But I really shouldn’t complain too much. The one I have was free and in perfect working order. ๐Ÿ™‚

        Liked by 1 person

      9. I find it is quite good to keep your basic machines separate from your fancy stuff. Machines that can do too much are often less reliable – all those functions crammed in! Besides, the settings and tensions are usually different for straight stitch than for embroidery, and they are certainly very different for each of those overlocker fancy seams.


      10. I definitely agree for both the need to keep settings separate and especially reliability. I can’t say I’ll never fall in love with a computerized machine, but I do like being able to service my own non-mechanical ones

        Liked by 1 person

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