I am making a few changes to this pattern and the way I am distributing. A free version shall remain here. Another version will be sold through Ravelry (you do not have to be a member of Ravelry to buy) here. Advantages to buying the pattern: 1) you get automatically notified of updates and 2) you get a pretty pdf 3)There are more leg cuff options in the for sale pattern, and a better fitting hip section. The reason that the for sale pattern will have more options is that I want to keep this free pattern simple and clear to explain. The for sale pattern is a more of when you're ready to move on to the next level sort of thing. If you've already used this pattern and enjoyed it, then buying a copy would also be a great way of saying "hey, thanks for the pattern and all your help."
Any problems and you can post here, pm or even email me: joeli dot caparco at gmail dot com.
Pic of new version:
FAQ:
What yarn do I need and how much do I need?
You can use DK weight yarn or Aran weight yarn. You will need 100-200 grams depending on the size you make.
What needles (and what size) do I need?
You will need a sets of DPNs (Double pointed needles). They come in sets of 4 or 5 and are used for knitting in the round (so there are no seams to sew). You can see some here. I'd get the ones that are 20cm long.
Alternatively you can use circular needles. Either get a long pair and use magic loop technique for the legs, or get a long pair and a short pair for the leg.
The size you need depends a lot on how tight or loose you knit. However for DK yarn the recommended needle size is 3.75—4.5mm and for Aran yarn the recommend size is 4.5—5.5mm.
Pattern
Swatching
The first thing you need to do is make a gauge swatch. To do this, cast on 20 stitches. Knit 1 row. Purl 1 row. Repeat these two rows until swatch measures a couple of inches long. Now lay your swatch flat on the table (you can take it off the needles) and take a ruler and measure how many stitches are in two inches (this is your gauge). Also consider whether you are happy with the feel of swatch. For example, it might feel really loose and you might see holes between the stitches. If this is the case you should go down a needle size. Or it might feel really stiff and tight. If this is the case you should go up a needle size. If you’re happy then you can rip out your swatch and get ready to cast on for your longies.
Body
Casting On
Now that you’ve got your gauge you can pick a hip size to make. The following table shows your options.
If you cast on 72; 80; 88; 100; 112; 120; 132; 144; 156
you will get a hip circumfrence of
and your gauge is 8 sts per 2": 18"; 20"; 22"; 25"; 28"; 30"; - ; - ; -
9 sts per 2": 16"; 18"; 20"; 22"; 25"; 26.5"; 29"; 32"; -
10 sts per 2": - ; 16"; 17.5"; 20"; 22.5"; 24"; 26.5"; 29"; 31"
11 sts per 2": - ; - ; 16"; 18"; 20"; 22"; 24"; 26"; 28"
12 sts per 2": - ; - ; - ; 16.5"; 18.5"; 20"; 22"; 24"; 26"
Cast on 72(80, 88, 100, 112, 120, 132, 144, 156) stitches.
Note that if you are using dpns, you will probably have to start dividing your stitches between the needles while you are casting on. You are going to divide your stitches between between 3 dpns (making sure there is a multiple of 4 stitches on each needle). You do not need the same number of stitches on each needle. When you are done casting on you need to join to begin working in the round.
Waistband
The waistband is going to be a ribbed waistband with holes for a drawstring. This is done as follows: *Knit 2 stitches, then purl 2 stitches; repeat from * until you get back where you started (to the end of the round). You have just knitted one round.
Now repeat this round until work measures 1”.
Next you need to do the eyelet round. This is for the drawstring to go through later. To do this, *knit 2 stitches together, yarn over, purl 2; repeat from * to the end of the round. Continue ribbing as before (i.e. knit 2, purl 2) for another inch. Work now measures 2” from beginning.
This is the ribbed waistband done.
Short Rows
Knit 1 round.
Work one short row as follows: Knit 36(40, 44, 50, 56, 60, 66, 72, 78) stitches, turn work, purl 36(40, 44, 50, 56, 60, 66, 72, 78) stitches, turn work.
You have now completed one short row and are back at the beginning of the round. For the following round when you get to the gap left by the short rows, close them using whatever method you prefer.
Work stockinette stitch (knit every round) for one inch. Be sure to measure on the front part of the longies (not across the back where you worked the short rows).
Work one short row as before.
Work stockinette stitch for one inch.
Work one short row as before.
Hips
Work stockinette stitch until work measures 1 inch less than half of the desired rise length (because you are only measuring the front, you are only measuring half the rise).
Gusset Increases
You’re now going to start the gusset increases.
Next round: Knit 14(16, 18, 21, 24, 26, 29, 32, 35) stitches, place marker A, knit 8 stitches, place maker B, knit 28(32, 36, 42,48, 52, 58, 64, 70) stitches, place marker C, knit 8 stitches, place marker D, knit to end of round.
Next round: Knit to marker A, make 1, slip marker, knit 8 stitches, slip marker, make 1, knit to marker C, make 1, slip marker, knit 8 stitches, slip marker, make 1, knit to end of round.
Next round: Knit.
Repeat these 2 rounds 3 more times.
Next round: Knit to marker D, place stitches between marker D and marker A on spare yarn. Cut yarn leaving a long tail (12-18” maybe?) and graft (using kitchener stitch) the previous 8 stitches with the next available 8 stitches (should be the stitches which were between markers A and B).
Legs
First Leg
The stitches that are left on the needles are the first leg stitches. Divide them evenly among all the needles if you are using dpns. When you get to the gap left by the crotch pick up 4 stitches from along the side. Join to begin working in the round. Knit every round until leg measures 2 inches less than desired length.
Seed stitch cuff:
Round 1: *Knit 1, purl 1; repeat from * to end of round.
Round 2: *Purl 1, knit 1; repeat from * to end of round.
Repeat these two rounds until cuff measures 2 inches, or desired length.
Bind off all stitches in pattern (knit 1, purl 1).
Garter stitch cuff:
Round 1: Knit
Round 2: Purl
Repeat these two rounds until cuff measures 2 inches.
Bind off all stitches in pattern (knit).
Second Leg
Place stitches that are on spare yarn evenly among needles and work as for first leg.
Finishing
Weave in ends. Wash, lanolize, and block if desired. Make an i-cord of apporipate length for the drawstring.
c 2010 Joeli Caparco. This pattern is for personal use only.
Although, on previous form, this is no indication of the actual size they'll end up. 
I am so new to wool but used to love to knit. My mum and I are about to attempt a very basic pair of longies together and if that's even vaguely a success I will be having a go at this.
