How Knitting Machines Work
by Sonja Kathleen
Hand Versus Machine Knitting
When you hand knit something, let’s say on two needles, you cast on all of your stitches and start knitting. The needles hold all the open stitches while you work on the one closest to the tips. When you get to the end of the row, you turn and work back. If you’re working in stockinette stitch, this means you knit one row, then purl one row, and so on.
The key parts of the knitting machine are a needle bed with up to 200 needles, and a knit carriage. The needles look like tiny latch hooks, and can be placed in 4 different positions: non-working, working, upper working, and hold. The knit carriage is a fairly flat piece of metal and plastic with a handle and lots of switches. When you cast on, a stitch is placed in each working needle, and when you run the knit carriage over the needles, each one knits. When you get to the end of the row, you don’t turn the work-you just run the carriage back the other way. This means you produce stockinette stitch without ever turning the work or making a purl stitch. The carriage and needles just make the knit stitch over and over again.
With hand knitting, you can knit in the round or flat. With few exceptions, knitting machines are used to knit flat pattern pieces, which are then assembled as in hand knitting. The difference is that with hand knitting, the knitting takes longer than the finishing, but with machine knitting it’s just the opposite-the finishing takes longer.
Although the machine can perform several stitch techniques automatically, the knitter must perform all shaping (as in hand knitting) by increasing or decreasing the number of needles in use at the appropriate time. To make a garment piece, such as a sleeve, the knitter places the correct number of needles into working position and casts on. Each time the knit carriage is passed over these needles, one row is knitted. The gauge has been worked out beforehand, so the knitter knows how many stitches and rows to knit for each piece. The work hangs straight down from the machine in front, with the reverse side facing the knitter, and grows towards the floor.
To shape the pattern piece, the knitter can use several different methods to increase or decrease. To increase the sleeve from the cuff, the knitter moves additional needles to working position at regular intervals. To shape the sleeve cap, the knitter decreases by moving the stitches to be decreased to adjacent working needles and placing the empty needles into non-working position before moving the knit carriage. It’s even possible to short row by placing needles into the hold position. These needles don’t knit when the carriage passes over them. Finally, the work is either cast off or scrapped off on waste yarn, which is used to keep open stitches from unraveling.
Purl Stitches
The advantage of machine knitting is, obviously, that you can produce stitches very quickly. The disadvantage is that you lose flexibility with regard to the types of stitches you can make. When you knit by hand, you can place knit or purl stitches wherever you like and without much extra effort, to produce ribbing, garter stitch, or textured stitches such as moss or seed. The machine simply can’t do this automatically without extra attachments. It’s possible to form purl stitches by hand on the machine, but this is usually not practical because there tend to be so many. You might as well knit the whole thing by hand.
There are two ways to form purl stitches automatically on the knitting machine-the ribber and the garter carriage (see Part IV). The ribber is a separate needle bed that attaches to the knitting machine such that the two beds are closely positioned, facing each other at an angle. Stitches on the main bed are knit and stitches on the ribber bed are purl. That’s great for a variety of ribbings and even several all-over fabrics such as fisherman’s or English rib. However, it’s not practical for fabrics where the position of the purl stitch changes from row to row, as in textured stitches. For these types of fabrics, you need a garter carriage, and garter carriages only work on standard gauge machines.
The garter carriage can produce a knit or a purl stitch at any position in any row. However, it moves automatically and at a much slower pace than you can move the knit carriage, so these fabrics can take much longer to produce. The good news is that you can set it to knit and leave the room. Garter carriages can be a little persnickety, and I find that conditions need to be just right or you won’t get good (or any) results.
Supporting Parts
Quality knitting machines include several components that make knitting much easier. These include the tension mast, metal needle bed, gate posts, fully functional knit carriage, row counter, extension rails and specialized tools. Hobby machines may not have some of these parts.
Tension Mast
The tension mast is a tall rod with dials and funny-looking wires attached to it, that stands up from the back of the machine. The yarn is threaded through it before being threaded into the knit carriage. Although it looks complicated, it helps to keep the yarn tension correct, and prevents loops from forming at the sides of the knitting. It has places for two different yarns, and helps keep them separate for stranded knitting.
Metal Needle Bed with Gate Posts
The needle bed holds the needles in place so they can slide back and forth while working. Metal needle beds are obviously more durable than plastic ones. A needle position indicator helps the knitter keep track of how many needles are selected. Gate posts are stationary metal pins between the needles that help the stitches to form and knit correctly.
Knit Carriage
The knit carriage is a key component for performing a wide variety of functions.
It has two yarn feeders, and a tension dial to control the stitch size. It has a variety of buttons, switches and levers that control the channels, or cams, on the underside of the carriage. The needles pass through these channels as the carriage is moved, which cause them to behave differently depending on which position they’re in and which cams have been selected. This is necessary to perform any of the stitch techniques (see Part III) or the machine equivalent of short row shaping, known as “holding.”
Row Counter
The row counter keeps track of how many rows have been knitted. On fully electronic machines, it also keeps track of the design and pattern rows.
Extension Rails
Extension rails give lace and knit carriages a place to “rest” off the needle bed when knitting lace or wide pieces, so they don’t fall off the ends of the needle bed when you need a little extra working room.
Specialized Tools
Specialized hand tools are used for a variety of knitting operations such as needle selection, cast on and cast off, stitch transfer, yarn conditioning, and stitch formation. These include cast-on combs, claw weights, transfer tools in various configurations, latchet tools, crochet hooks, needle pushers, cast-on thread, yarn wax and tapestry needles. Other tools are included to help maintain the machine, including oil and a hand brush. Most machine knitters purchase additional tools such as garter bars, long cleaning brushes, and ball winders.
Next Installment: What knitting machines can do (3/4)
