Cabled casting on
is knit and purl, yin and yang.
Choose your side with care.
Introduction: The cable cast-on, in essence, consists of using the right needle to pull a loop of yarn between the last two loops on the left needle, bringing the new loop around and placing it on the left needle. (It is sometimes called the knitted cast-on, but I prefer to reserve that term for a similar technique with very different results.... to be discussed in a later post.)
Properties and benefits: It has a firm, yet flexible edge, with some elasticity, though there are much stretchier cast-ons.
As it is constructed via a knitting action, it strongly demonstrates the curling and esthetic properties of knitting.
Double thickness edge loops enhance wear resistance and shape retention.
The edge loops are convenient for picking up stitches (though the best pick-up technique to match an existing fabric will vary by stitch pattern and situation.)
The cable cast-on is an excellent choice for casting on to the edge of an existing piece of knitting.
No advance planning for length is required.
Esthetics: tidy, attractive, looks like a half braid.
Techniques and Variations:
Getting started: two loops need to get on that left hand needle in the first place, in order to be able to pull another between them. A common method of creating the first two loops is to tie a slip knot on the left needle and pull the second loop knitwise through the slip knot, placing it on the left needle, adjacent to the knot.
The disadvantage to this method is that the first two loops are created differently than the rest, and therefore have different esthetic and functional properties.
TECHKnitter, who eschews the slip knot in particular as being an inflexible beginning, has developed a method of making the first two loops "provisional," to be discarded at the end of the first row (see Resources, below.)
Another possibility is to create a flexible first stitch (say, with a simple backwards loop) and pull the second one from behind it, then carry on as per normal.
In this case, you do need to keep a finger on the first two stitches initially, as they are quite unstable until the third has been formed. This beginning is a perfect match for the remaining stitches, and the tension of the first two stitches may be precisely adjusted by tugging the tail.
Note: it is a good idea to keep the loop just made loose until the needle has been inserted for the next loop. If you snug it up prematurely, it can be difficult to re-insert the needle. This is also your means of fine tuning the gauge of the cast-on edge.
You can place the loop directly onto the left needle, or give it a twist. The twist doesn't change the appearance, but does make the edge firmer and less flexible - a property that may or may not be desirable, depending on the project.
Casting on purlwise:
Yup - you can do the exact same thing purlwise, and the appearance is identical to the reverse side of the knitwise cast-on. (Actually, the edge loops slant in the opposite direction, making it a mirror image.)
This is a good time to elaborate on the fact that the cable cast on has strong knit/purl properties, both esthetically, and with regard to curling.
--------------knit side of cast-on------------------------------------purl side of cast-on--------------------
Placing the purl side of the cast-on to the right side of a stockinette fabric creates a lovely decorative edge and counteracts excessive curl nicely. Bear in mind that when knitting flat, the front side of the cast-on will still be facing when working the first row. When joining to knit in the round, the reverse side of the cast on will be facing. Since the properties of the two sides are so different, one must plan ahead.
Alternating cable cast on:
This is exactly what it sounds like, alternating between knitwise and purlwise loop formation, then knitting the knits and purling the purls in the first row. As a way to begin 1x1 ribbing, it mimics the look of a tubular cast-on reasonably well.
The crossing back and forth of the yarn when switching between knitwise and purlwise is visible, but blends nicely into 1x1 rib. Unfortunately, the irregularity is quite prominent in wider ribs, making the technique unsuitable.
Casting on additional stitches to knitting in progress:
I'll cover this in detail in a post dedicated to the topic; suffice it to say that the two stitches at either edge of a row of knitting in progress are an excellent pair between which to draw a new loop. If casting on at the end of a row, you will need to first turn the work. Also, the first new loop can create a bit of hole which needs dealing with... more on that later. As always, a choice must be made as to whether to perform the technique in knitwise or purlwise fashion, depending on the desired properties of the edge.
Additional Resources and Tutorials:
There are many other videos discoverable by Googling "cable cast on"; all the ones I've perused begin with the slip knot method, and most twist the new loop. I've yet to see a video tutorial for the purlwise version.
Anything to add?