I posted on flickr a sweater I knitted for my brother's dog Maci, and have since been asked a couple times for the pattern. I've never written a pattern before, but here's what I came up with. Feel free to use or modify it, and let me know if you have any trouble or suggestions.
Maci's Dog Sweater
Materials & Notes:
Worsted/medium yarn, size 4 double-pointed needles (I use five, but you can probably get away with four)
Maci is a miniature Chihuahua, about three pounds, and this pattern fit her almost perfectly. If you need it slightly bigger, one idea is to use the same pattern, but use size 7 or 8 needles.
Before you start, cut off about a foot of yarn and set it aside for later
(works tail to head [or waist to neck]) Cast on 60 sts evenly onto three needles (these are numbered 1, 2 and 3, with 2 being the middle needle)
Waist cuff: work in the round as knit 1 purl 1 for about 2" (or whatever looks good)
Body: knit in the round for 4-1/2" (or size according to dog)
Shoulder Area: when you're ready to make the arm holes, it gets kind of tricky (this is the part I made up myself):
- knit across needle 1
- on needle 2, bind off the first 8 sts, slip the next four sts, then bind off the last 8 sts (with the last one binding off with the first st of needle 3). Knit across needles 3 and 1. The working end of the yarn should be at the end of needle 1 (between 1 and 2), and there should be just four sts on needle 2 - hold these on the needle or with a piece of yarn so they don't get dropped, as we will be coming back to them later
- purl back across needles 1 and 3, then knit back across needles 3 and 1, and repeat this (I call this stockinette) for about ten rows total - basically, this needs to be as tall as the eight bound off stitches are wide. You should finish the stockinette stitch at the end of needle 1 (just before needle 2).
- when the stockinette is finished, use the foot length of yarn you cut off and set aside at the beginning and work the 4 sts on needle 2 as stockinette for the same number of rows as you did the needles 1 and 3 stockinette. This forms the "chest" section - the section between the arm holes (which for Maci are sized between a quarter and a half-dollar, but it depends on how big your dog's legs are)
- when the chest section is as tall as the needles 1 and 3 section, you're ready to continue working in the round. With the working end of the yarn at the end of needle 1, cast on 8 sts onto a fourth needle, the knit across the 4 sts from the top of the chest section, then cast on 8 more sts. You should now again have 20 sts on each of the three needles. Finish knitting this row across to the end of needle 3
Neck area: knit one row all the way around. Next, decrease every other row, until you end up with 50 sts total (15 on needle 1, 20 on needle 2, 15 on needle 3). To do this, knit across needle 1, and knit the last two together (sts 19 and 20). Knit across needle 2. On needle 3, knit the first 2 sts together through back loop, then knit out the remaining sts on needle 3. For the next row, knit all sts. For the next row, k17, k2together, k20, k2together through back loop, k17. Alternate this knit together/knit normal row pattern 5 times total, until you are left with 50 sts. Continue knitting these 50 sts in the round until the entire neck measures about 3" from the top of the arms holes
Neck Cuff: work to match the waist cuff (same pattern, same size). When worked to proper length, bind off.
Arms: you will work these one at a time, but they will both be worked the same way
- with four needles, pick up 8 sts on each of the four sides of an arm hole
- With a fifth needle, work these with the same pattern as the cuffs, for about an inch (or to the length of the dog's foreleg up to elbow)
- Do not work a cuff onto the arm - just rib the arm and then bind off after an inch
- finally, work the second arm the same as the first
See more patterns and projects on my Knitting page.