“Interlocking” or “double filet” crochet is a colourwork technique—a way to crochet images, patterns or text using two colours of yarn or thread.
Each motif consists of two separate but interwoven pieces of mesh fabric, one in each colour. You make these in alternating rows, using a basic pattern of double crochet and chain stitches called filet crochet (which you might already know).
It’s crochet with aspects of lace-making, weaving and embroidery combined. It takes some getting used-to, but it’s easier than it sounds!
Contrasting Colourwork
Colourwork in crochet can be frustrating: stitches rarely interact cleanly, and carried thread is always getting in the way. Interlocking crochet sidesteps both of these issues.
Unlike tapestry crochet or intarsia, interlocking crochet doesn’t ask you to change colours mid-row, so there are no bobbins to maneuver and no unused colours to carry.
In contrast with mosaic crochet, you only work into stitches of the same colour, and you work flat without having to cut thread (or switch hands at row end). There are normally only four ends to weave in per motif.
Interlocking crochet has a unique, durable double construction that’s ideal for making sturdy patches to pin on backpacks and hard-wearing functional pieces like dish towels and tote bags. Worked in looser gauges and breathable yarns, Interlocking Patches can be extended or combined to make blankets and clothing.
The drawbacks? Interlocking crochet has some unique design constraints; it’s relatively time-consuming, and it can be tricky to figure out just where stitches need to go and how to get them there. Once it “clicks,” though, the technique is surprisingly straightforward, and these patterns are designed to highlight that!
Required Skills
Interlocking crochet is tricky—you’ll have to move your hook in unfamiliar ways, and you’ll need to have a strong grasp of stitch “anatomy” in order to keep your bearings, but if you’ve ever made a granny square, you can get there.
If you’re new to crochet, a few video tutorials should be enough to get you started. Better yet, meet up with a friend or relative who crochets. You might even introduce them to something new—interlocking crochet is pretty niche, even among calloused crochet wonks.
Interlocking Patches use ch, sl, dc, (dc,tr)tog, (tr,dc,tr)tog, and some also use dtr, so know these before getting started. There are also “knot stitches” (a small picot), sts worked “around the post” and extended sts, but these are optional. Borders ask you to work in and join rounds; some use hdc, blo and post sts.
Patterns consist of diagrams for every row and a simplified form of written notation, which is illustrated and defined in the Quick-start Guide. Standard notation is used occasionally throughout and in border instructions.
Interlocking crochet is easier to do than it is to explain. If you get confused at any point, just look at the diagram for the row you’re on, and try to “make it like the picture!”
Common Abbreviations (US Terms)
blo........... back loop only (usually back of work)
ch............ chain (stitch)
dc............ double crochet (yo once to start)
dtr........... double-triple crochet (yo 3 times to start)
hdc........... half-double crochet (yo once to start)
sc............ single crochet
sk............ skip
sl............ slip stitch
sp............ space
st............ stitch
(X,Y,Z)tog.... work sts X, Y and Z together (in that order)
tr............ triple crochet (yo twice to start)
yo............ yarn over