I considered writing a full post containing all my notes for Silver streak, but decided to split it up – I’m a slow writer with a full schedule and this might be easier to navigate. Remember, comments and questions are always welcome.
Most of the time, length alterations are the easiest things to change about a pattern, particularly in the case of body length, as only rudimentary subtraction is needed. For example, take the back of ‘Silver Streak’ (figure A.): if you only need to take off a couple of inches, you’d work 1.5” instead of 3.5” before beginning to decrease. It’s a little more complicated to remove something like 6”, but barely – just figure out how many stitches should be there and cast on accordingly.
In this case, 83 sts were cast on for the smallest size and were worked even for 3.5”. Since the gauge is 6 rows to the inch, the first decrease row of the pattern falls on row 21. Subsequent decreases follow on every 14th row, and will therefore fall on rows 35, 49, 63, 77 and 91. Since only 36 rows would need to be deducted for the new length, all you’d need to do is cast 4 fewer sts and work for 2.25” (about 13-14 rows) instead of 3.5”.
The front’s a different story – increases are worked from hem to neckline, as can be seen in the smallest size’s chart at the top of this post.
In order to alter the length of this piece (the original schematic with the patterned section shaded in blue is shown in figure B.), there are two choices: One, you could calculate how many increases should be where the new hem will sit and cast on accordingly as for the back. Two, you could cast on as in the pattern but increase more often.
Both have advantages and disadvantages: the former’s front hem will be comprised of two different angles, but will provide more coverage since the front edges do not sit at a steeper angle than the original cardigan (fig D.; no, they’re not in order);
the latter’s hem will be pretty much straight, but might recall a cutaway jacket due to the more acute angle (figure C.).
In any case, calculating regularly spaced increases calls for the same calculations needed to recalculate a sleeve’s length or how to distribute increases (or decreases) evenly across a row. I’ll go on in detail about how to go about it in Part Two another day, but the impatient can google ‘magic formula knit’ to find out more.