Knitting needles are the primary tools of the knitter. They come in a variety of shapes, sizes, colors, and materials, and an avid knitter will often collect quite a large set of needles.
One of the key properties of knitting needles is the Needle size. The size of a knitting needle is measured by the diameter of the shaft, and this value determines the size of the stitches created with those needles, thus playing a key role in determining Gauge.
There are a number of materials knitting needles are commonly made from, with each providing different advantages and disadvantages.
Aluminum and plastic are the most common materials available. Plastic needles can have a variety of finishes, some quite smooth, while others are more waxy, which increases friction. Aluminum needles, on the other hand, are generally quite smooth, and thus are considered the fastest to work with, though this may also result in more dropped stitches. Both are quite light, and while aluminum needles tend to be fairly rigid and cool to the touch, plastic needles are generally the opposite.
Bamboo and wood also also fairly common these days. Both are fairly light and warm to the touch, and given time will develop an aged finish due to exposure to oils in the hands. These needles are generally slower to work with, as they provide more friction; however, this may be advantageous to beginning knitters or when working with a "slippery" yarn. Quality is particularly important with this style of needle, as lower-quality needles may break during use. Wooden needles from different kinds of wood will have different properties -- weight, texture, etc.
Lastly, while less common, steel needles are still being made. They're most common as double-pointed needles, and are favored by lace knitters for their rigidity (though they're also nice for high-gauge sock work).
Other materials not commonly used today include casein (a milk derivative), celluloid, and animal sources like ivory and bone.
Knitting needles come in a three types:
- Straight needles are used for standard back-and-forth knitting.
- Circular needles are two needles joined by a length of cable, typically nylon. These are quite versatile and can be used for both back-and-forth and Circular knitting, though in the latter case, they tend to be limited to larger-diameter pieces.
- Double-Pointed needles are short needles with two pointed tips. Like circulars needles, they are mainly used for circular knitting, however they can also be useful for standard knitting as well, due to their smaller, more maneuverable size which makes them ideal for small projects. Additionally, when working in the round, double-pointed needles have the advantage of not being limited to the size of piece that can be created.