interlock bind-off

i saw this article by jeny on the interlock bind-off and i wanted to really understand how it worked so here’s my own notes

structure

drawn diagram of two rows of knitting, showing how each stitch loops through the one on the row below
regular knitting
the bind-off, which is the same as the previous diagram but the top row also has each stitch interlocking with its two neighbours on the same row. the intersections have arrows pointing to them with the label “interlocking”
the bind-off

the structure is a regular knitted row, except every stitch is interlocked with the ones on either side

sewing knit/purl stitches

traditionally, stitches are made by pulling a loop through the stitch on the row below. it’s a knit stitch if pulled from back-to-front, and a purl if pulled from front-to-back

we’re sewing in the same direction as we knit, which is traditionally right-to-left (and the rest of the notes assume this)

a stitch, with labels pointing to the in and out movements

each stitch requires two movements, an in and an out.

a knit stitch, with the in movement labelled “(1) in, b2f, p” and the out movement labelled “(2) out, f2b, k”

for the knit stitch:

  • going in means moving the sewing needle from back-to-front (b2f), which is the same direction as if you were about to purl (p)
  • going out means moving the sewing needle from front-to-back (f2b), which is the same direction as if you were about to knit (k)
a purl stitch, with the in movement labelled “(1) in, f2b, k” and the out movement labelled “(2) out, b2f, p”

for the purl stitch, it’s the opposite:

  • going in means moving the sewing needle from front-to-back (f2b), which is the same direction as if you were about to knit (k)
  • going out means moving the sewing needle from back-to-front (b2f), which is the same direction as if you were about to purl (p)

a mnemonic that needs workshopping:

in with inverse, out the same

  • a knit stitch goes in purlwise (inverse) and out knitwise (same)
  • a purl stitch goes in knitwise (inverse) and out purlwise (same)

joining

a join, with the movements labelled “(1) in, (2) join, (3) out”
in, join, out

joining happens in between the in and out steps and is when we thread through the previous stitch on the same row

a join, pointing at the top crossover (crown join)
a join, pointing at the bottom crossover (leg join)

the join will make the thread cross over at two points: the crown (top) and the leg (bottom). if the stitch goes under at the legs, it must go over at the crown, and vice versa. this poses a problem if we are binding off in-pattern and have a knit and a purl next to each other. we would want the purl to always be behind the knit, but here we have to pick either the crown or the legs

the original by jeny follows the leg pattern, and i think this generally looks better too since you get a continuous pattern upwards and then a “half” stitch of the cast-off

a f2b, knit join
a b2f, purl join
crown leg
knit b2f, purl f2b, knit
purl f2b, knit b2f, purl

full stitch

the same join stitch as earlier, with the movements labelled “(1) in, (2) join, (3) out”
in, join, out
general knit purl
1. in inverse b2f, purl f2b, knit
2. join (leg) same f2b, knit b2f, purl
3. out same f2b, knit b2f, purl

first and last stitch in the round

here i join the first and last stitches. this means skipping the join step for the first stitch (only doing in and out), and adding a join for the last stitch (in, join previous, join first, out). then sew in ends

speeding it up

pulling the needle all the way through takes time! we can speed it up by threading the needle a few steps before pulling all the way through. we have to be careful when we do this, though, since this pulls quite tight, and we want to be careful that e.g. the we don’t lose the loop from the previous stitch we are about to join to

jeny’s instructions combine the out and in stitches specifically for the 1×1 ribbing pattern

i’ve found you can generalise this and also add in a join:

the steps described below, with the movements numbered and labelled (1) out (2) in (3) join
out, in, join
  1. thread out (same) for the previous stitch
  2. push the previous stitch off the needle
  3. thread in (inverse) for this stitch
  4. join (leg: same) through the loop of the new stitch
    • you can do this without orienting the loop by pointing the needle the correct way and then wrapping the yarn coming off the needle around the needle
  5. pull through
  6. inspect the tension of the new stitch and adjust if necessary
  7. repeat

bonus

as mentioned in the original article, this structure is similar to the long-tail cast-on, which is the same as the backwards loop cast-on with one row of knitting. the backwards loop cast-on is making just the twisted-together loops, and in the long-tail cast-on it’s the crossing over of the loops that creates the twisted join. structural equivalence!!

also, like, it’s not at all necessary to cast on in pattern, and the same is true for binding off. you can still make a lovely looking bind off like this by just using the knit (or purl) pattern the whole way along. especially since the edge rows have different tension (due to not having stitches on all sides) and will always look a bit different anyway