The pieces of your garment are complete; now it's time to put them together. Attaching sleeves and hems requires patience and careful attention to avoid puckering or pulling, and there is a certain order to putting pieces together, so don't skip this important section.
ORDER OF ASSEMBLING
When you’ve finished crocheting the pieces for a sweater, it’s time to assemble them. (Before you thread your yarn needle, you should block the pieces first to get the most professional-looking results.) There is a certain order to putting pieces together, and for good reason. Not to follow the order is like putting the cart before the horse. All sweater patterns have finishing directions at the end. The finishing directions will state what and when to sew and how to complete unfinished edges like a neckline. As an example, here’s what you should expect to find for a crewneck pullover that has dropped-shoulder sleeves: First, sew the shoulder seams. Second, finish the neck edge (with a neckband, trim, etc.). Third, sew the sleeves to the body of the sweater. And fourth, sew the side and sleeve seams. This is done in one continuous seam, from the end of the sleeve to the underarm and then down the body of the sweater to the bottom edge.
MARKING FOR ARMHOLES
The simplest sweater to make is one with dropped shoulders. Although the top edges of the sleeves are straight and the side edges of the body are straight, it can be a little tricky to sew the sleeves evenly to the body. First, let’s get a handle on how to mark for the beginning of the armholes, then we’ll discuss how to sew the sleeves evenly in place.
Where or how to mark for the armholes depends on the way a sweater direction is written. You will encounter two ways, and both are acceptable. The first way is when you have crocheted the stated amount of inches to the underarms. The directions will say: “Mark beginning and end of last row for beginning of armholes.” To mark, simply fasten one safety pin to the beginning of the last row and one to the end of the last row. Continue to work following the directions, until you have reached the armhole measurement stated in the directions. Before you join the sleeves, join the shoulders (referring to the finishing directions).
The second way is when the directions have you mark for the armholes after the shoulders are joined. To mark, lay the sweater out flat on a flat surface. Measure down from the center of the shoulder seam along the side edge of the back (or front) to the stated amount of inches (take care not to stretch the fabric), then fasten with a safety pin. Repeat along the front (or back) side edge, then mark for the armholes along the opposite front and back side edges. Just to make sure that all things are equal, also measure from the safety pin marks down to the bottom edges. Make any adjustments necessary.
Now that you know how to mark for the armholes, here’s how to center the sleeves in the armholes. Using a tape measure, measure and mark (using a straight pin) the center of the top edges of the sleeves. Place each sleeve along the armhole edge between the armhole markers and so the straight-pin mark is centered in the center of the shoulder seam. Join each sleeve following the seaming directions. Don’t forget to remove all the pins!
Whenever you have two pieces that are to be joined together, they must be the same length. For a cardigan, both fronts and back should be the same exact length. Mismatched seams will give you a lopsided sweater that will not only fit poorly but also look silly. The same goes for sleeves. Each should be equal in length so that when you wear the sweater, each cuff will fall at the same point on both wrists.
There are two ways to tackle the issue of length. The first is to measure precisely using a tape measure. Lay the piece on a flat surface and measure the length without stretching the piece in either direction. Pulling on the fabric to make it meet a measurement is only a temporary solution. Yarn has a memory and will spring back to its original shape once tension has been released.
The second way to ensure equal lengths is to count rows. This is the most reliable method. You can either opt for a row counter or go for the old paper and pencil. Mark or check off the row as you are about to crochet it, so you’ll always know where you are and have an accurate count. But just in case a row or two is missed, recount the rows just to be absolutely sure of the count before you fasten off the last stitch.