Overlock for sewing machines

Not a mock-overlock stitch and not a zig-zag, this attachment makes a proper overlock stitch with two additional threads, incorporating a real sewn stitch into it. Rubylock overlock attachment really allows you to sew and overlock in one operation, and it works even on old straight stitch machines.

Rubylock overlock attachment mounted on a 1902 Singer 27K machine. Just because I could. 😀

Ruby is trade mark of Toyo Seiki Industry Co., a.k.a. Toyota. Ruby zig-zaggers and buttonholers are well known for their quality, so when I saw this rarity, I obviously had to get it. £10 well spent!

This attachment mounts onto a sewing machine instead of the foot. It is driven by a fork fitting around the needle clamp like any other active attachment. It can be used with virtually any machine as all it needs is straight stitch. It comes with mounting brackets for low shank and high shank machines, plus brackets for left-set and slant needle machines can be ordered separately… well, may be not anymore. 😉

I thought Rubylock must be from 1960s-1970s because it came with a bonus zigzagger. But of course it couldn’t be that old since overlock had only been introduced to home sewers in 1967 with Juki’s Babylock! A bit of research shows that trade mark “Rubylock” was first used in 1989! It was filed for registration in USA in 1994, so this attachment is from 1990s!! And I thought nothing good came out of that decade. 😉

The sewing machine is sewing its usual straight stitch, and Rubylock cleverly weaves the two additional threads into it wrapping them around the edge of the material. This is real overlocking, in the sense that the wrapped threads lie loosely on the fabric without pulling it. They interlock on the edge.

The resulting stitch is really very good. You control the straight stitch as you normally do on the sewing machine, and you control the overlock with the tensioners on Rubylock. Besides the classical overlock stitch, you can also get wrapped edge if you change the lock thread tensions such that one is much looser than the other. The tighter thread then blends with the sewing machine thread making for a bolder stitch on one side of the fabric. This can be on either side!

The mechanism

Rubylock has two loopers that weave the thread around the sewing machine thread.

It is a very lightweight mechanism – it must be because it is driven by the needle clamp! It’s recommended to run it at low speeds – this is not a fully fledged overlocker machine! Don’t abuse it, and it will perform beautifully. I found it to work well at my normal sewing speed for clothes – with short seams, you don’t get to neckbreaking speeds anyway, not like with making curtains, for example.

Usefullness

Will I use it? That’s the real question, isn’t it – the proverbial eating of the pudding. Well, I think I will use it.

Rubylock attachment is of course by no means a replacement for an overlocker machine, and I would still use a separate overlocker in most cases. But sometimes you just need to do a short overlocked stretch, and setting up Rubylock is certainly quicker than an overlocker, plus you don’t need three extra spools of thread but just two. Why not use zig-zag in such cases though? You certainly can, if you are on a zig-zag machine, but I normally use straight stitch only machines for straight stitch. Besides, zig-zag, even when done with an overedging foot, is still not as good as this overlock, and you need to change machine settings for it. With Rubylock you just swap the foot for the attachment and you don’t need to change machine settings in any way.

In my comparison of zig-zag and overlock, I found zig-zag to be very useful for overedging fine fabrics where even 3-thread overlock is too bulky. Rubylock makes a lighter stitch than 3-thread overlock, and although zig-zag is still less bulky, Rubylock overlock has the advantage of already containing the main sewing straight stitch in it, so the total sum of straight stitch and overedging with Rubylock is pretty much the same as straight stitch with zig-zag overedging. The two stitches are of course done in a very different manner, and I would imagine that the preference will vary depending on the fabric. It’s nice to have options though!

Another application for Rubylock that I foresee in my sewing room, is decorative overedging. By regulating the tensions on Rubylock, you can get the overedging stitch skewed to one side – without pulling the material. You can then use differently coloured thread to get an embroidery effect of one stitch inside another. And if you set the tensions for wrapped edge, you can use woolly nylon for wrapping and silky top stitch thread for the topstitching, all in one and the same operation as sewing the main stitch and without changing any settings on the sewing machine (except may be stitch length). This is rather better than wrapped edge with 2-thread overlock stitch on a regular overlocker.

In a word – I am impressed. This looks like a very interesting new option for occasional overlocking, for narrow seams on delicate fabrics and for decorative overedging. This attachment is certainly not for high volume heavy duty work, but if used correctly, I believe it to be robust enough to last a very long time. ☺

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