It took a third overlocker to sort out the second. Not as a doner of parts, but of ideas.
After my overlocker trials with AEG 760 versus New Home 743 (both Juki), I kept wondering why the AEG behaved so strangely (with correct needles, it favoured thin needles for thick fabric – quite illogical). Plus, it still wasn’t sewing as well as I felt it could. Plus I really was still looking for a second overlocker that could do all the fancy stuff that New Home 743 can’t do comfortably, like narrow hemming or flatlock.
The third overlocker
Then I came across another incarnation of the Juki design: the Singer 14HD854. This is a “heavy duty” version of their more common model 14SH754, the difference being (according to the write-up) in a more powerful motor, a wider knife for handling thick fabrics, a better feed and a brighter light.
As you can see, it followed me home, with its 10 year warranty in tow! (You get a standard 2 year warranty from the manufacturer, and then depending on where you buy, you can get extended warranty from the dealer. Mine came with 10 years, I’ve seen 15 years elsewhere, but the price difference wasn’t worth it for me, but most other places just gave the standard 2 years for yet more money! Go figure.)
So far, Singer HD passed every test with flying colours, so I think I’ll be keeping it (30 day free trial included). It feels very much like my old New Home 743 – very robust. There was only one thing: it was making too much noise, sounding like it was run dry. But how can it be – it’s brand new! So I took off the covers to have a look.
There was a puddle of oil on the left side cover. Side cover? Yes, it seems the box had been stored or transported on its side, so the oil leaked out of the joints leaving them dry. 😦 Easily fixed!
While oiling, I had a good look at the construction. I don’t know what the standard model looks like inside, but this HD one has many Teflon rings and washers (black or white parts in the photos) that are self-lubricating, so frequent oiling will not be required.
Teflon releases lubrication under friction, so it may start out a bit dry, which is why it’s a good idea to oil it a little to get it going. Then it would only need topping up if the machine was left motionless for a long time (or that’s the theory, anyway).
Size 100/16 overlock needle
Singer HD came set up with #2022 (HAx1SP) domestic overlock needles size 100/16. Such a heavy size is very unusual for a domestic overlocker! Schmetz or Organ don’t even make overlock needles in this size! (But Singer does, sold in a mixed size pack only). Every other overlocker manual will tell you to use needles size 75/11, 80/12 or 90/14, never beyond that. But why not?
Because needles of different sizes don’t just vary in thickness, but also in length! So the thicker needle becomes too long for the machine. When I tried size 100 needles on AEG, it positively choked, although it was already doing quite well on size 90 and even better on size 75. Which made me wonder whether its needle bar was set a little too low since it seemed to favour shorter needles.
I turned the hand wheel to bring the needle bar to its heighest point, and there was still about 1mm clearance between the needle clamp and the “ceiling”. So I loosened the holding screw and pushed up the needle bar as far as it would go. Be careful here not to twist it, or the needles will get out of alignment as we’ll see in a moment. :-s
Anyway, I did manage to keep it straight, and immediately the stitching improved! The overlocker now behaves logically: it requires thicker needles for thicker materials, and with size 90 and still using the cheap and fluffy thread, it produced a very decent stitch both on dense faux angora knit jersey and the evil textured thick jersey. Success! 😀
In fact, size 90 needles is what it favours for almost anything, as it should be. Size 75 are very thin and start bending under the thread tension when used on thicker materials, these needles should only be reserved for the fine stuff like chiffon or thin mircofibre knits.
How an overlocker forms a stitch
Overlockers have always mystified me. All those funny shaped loopers moving so strangely and so fast creating a crocheted stitch… But now that I got myself into adjusting the needle bar, I had to see what was going on, because I had this bright idea to convert the AEG from the longer domestic needles to the shorter industrial DCx1F used by New Home, thinking that the original needles may work better with these loopers (they didn’t). That involved bringing the needle bar down by some 3mm, and of course I got it twisted out of alignment, and the needles started colliding with the loopers, and I had to understand what was going on in order to fix it… :-s
So then, here we go. Starting with the needle bar in the top position, as the needles come down, the upper looper (green) moves to the left and the needles are inserted into the big thread loop that it’s carrying.
The upper looper now moves to the right while the needles are still going down and the lower looper is moving to the left. The upper looper drops the blue lower thread from the previous stitch, it forms the edge. The needles are now carrying the green upper overedge thread wrapped around them and deposit it on the top of the fabric (or the needle plate pins). The red and yellow needle threads are taken to the underside of the fabric, just like in regular sewing machines. The lower looper drops the red and yellow needle threads it was carrying from the previous stitch, they form the little dot-stitches on the underside.
Now the lower looper changes direction and is moving to the right, so that when the needles are at their lowest point and are just about to go up, the tip of the lower looper comes behind the needles and picks up the needle threads, so they are now wrapped around the lower looper.
As the needles are moving up and when they clear the looper, the blue lower looper is still moving right, but the green upper looper has now changed direction and is moving left, so the two loopers meet, with the upper one passing behind the lower one taking up new blue thread ready for the following stitch.
Gosh, that is confusing!!
The important conclusions however are these:
- The shapes of both loopers and the needle tips must fit together very precisely.
This is why you absolutely need the right needles!
- The loopers and needles must not bend even slightly under the tension of the thread and fabric.
So the needles must be thick enough for the fabric you’re sewing. And if it’s your loopers that bend… other than blaming the quality of manufacture, I’d say that your machine is incapable of handling the thread tension you’re trying to use.
For example, the AEG cannot manage a flatlock seam (with regular cheap thread) because it requires extremely high tension on the lower looper. This is just not happening here. May be it would work with different thread, but I didn’t try it. The Singer HD, on the other hand, does it with ease, with the same thread, but both loopers are shaped slightly differently. May be that’s the secret?
- The quality and stretchiness of the thread will make a huge difference.
May be that’s what makes Coats Moon such a nice thread for overlocking? It’s less densely spun, so it’s got a little tensile stretch to it which may reduce the pull on the needles and loopers. Anyway, that’s my theory. 🙂
Clearly, it has limitations. But do I still like it? Yes! It is very smooth running, and the internal layout makes it very easy to oil. Singer HD has a very convoluted layout, it’s hard to see inside or reach many of the joints. Good thing I won’t have to do it often thanks to the Teflon!
I’d say, the AEG 760 is a good solid overlocker for light to medium fabrics. It can do heavier stuff too, but only with better thread. It does 3- and 4-thread overlock and 3-thread rolled hem, very nice, but forget about flatlock.
I’m keeping it until I decide on the Singer HD, I want to be sure it can do the fine stuff as well as AEG.
And also this
The Singer 14SH644 is the predecessor of my HD, so a very similar machine. Here is an excerpt from the manual:
In an emergency? Oh yeah!!