Instead of starting a new search for a hat pattern or some other yarn, I decided to adapt the pattern to work with worsted weight I had on hand. The step-by-step process I used follows. I hope it helps you when you are faced with a similar situation.
- Compare the yarn used in the pattern to the yarn you plan to use. The yarn used in the pattern was 100% superwash merino in a DK weight. My yarn was 100% superwash merino in a worsted weight. I would expect my finished hat to be thicker and heavier than the one in the pattern, because worsted weight yarn knits into a thicker fabric than DK weight. Other than that, I would expect the drape, elasticity and overall properties to be the same because the yarns are the same fiber.
- Find the pattern needle size. The pattern called for a US size 6 needle, which a standard size to use with DK weight yarn. This tells me the hat is not meant to be drapey, lacey or open weaved. To create a similar result, I used a US size 8 needle, the size recommended on my yarn label, and a standard size for worsted weight yarn. My knitted fabric should be the same density as the hat in the pattern.
- Find the project gauge and knit a gauge swatch. The gauge for the hat was 21-24 stitches and 30-32 rows = 4 inches. My gauge swatch on size 8 needles and worsted weight yarn was 18 stitches to 4 inches and 26 rows to 4 inches. Write these numbers down, you will use them again!!!
- Convert the pattern with a little math. The hat pattern instructions said to cast on 110 stitches. How many should I cast on?
- 21-24 stitches = 4” (Divide 21 and 24 by 4 to get the number of stitches in 1 inch) the range in the middle is 5.5 stitches per inch. I will use 5.5 as the number of stitches per inch in the original pattern.
- 110 stitches cast on times 5.5 stitches per inch = 20” The hat is 20” around. I want to cast on enough stitches to get a 20” hat.
- My gauge is 4.5 stitches per inch. 4.5 stitches per inch times 20 inches = 90 stitches. I will cast on 90 stitches to make a hat 20" around.
4. Consider rows per inch. The next changes I needed to make were in shaping the hat. The pattern row gauge is 30-32 rows for four inches or about 7.5 rows per inch. The pattern calls for a 4 row repeat to be completed 9 times: 4 rows times 9 repeats equals 36 rows. 36 rows divided by 7.5 rows per inch is between 4 and 5 inches. The 9 four row repeats will measure between 4.5- 5 inches tall.
I want my hat to be shaped the same way. My row gauge is 26 rows for 4 inches or 6.5 rows per inch. Since my gauge has fewer rows per inch than the pattern gauge, my hat will be too tall if I do not modify the pattern. My formula is 6.5 rows per inch times 4.5 inches = 29 rows. BUT the pattern repeat is in fours. The number nearest 29 that is divisible by 4 in 28. If I complete 28 rows, or 7 repeats (28/4 = 7),my hat will be about 4.5 inches tall just like the hat in the pattern.
5. Decreasing and shaping the crown. Hats typically decrease by working a row with evenly spaced decreases (to keep the hat symmetrical) followed by several rows knitted even with no decreases. The hat in the pattern has 110, stitches and begins decreasing with a row of K 9, K2tog. How did the writer decide what to do? The total number of stitches, 110, divided by 10 = 11. The decrease is worked over 11 stitches ( k9 + k2tog = 11). How do I begin my decreases? Divide my total number of stitches, 90 by 10 = 9. My first decrease row will be worked over 9 stitches (K 7 + K 2tog = 9). The pattern suggests working 4 rows between each decrease and I did the same to stay in pattern. After finding the starting point for decreasing, I followed the pattern instructions to the end. The decreases work without the hat being too tall, because I omitted both the decrease and the pattern repeats that were included for for more than 90 stitches.
A transformed pattern success!