Toe-Up Heel-Flap & Gusset Socks on a Circular Sock Machine (CSM)

Beginner Worsted Weight

Sizes: S (M, L, XL)
To fit foot circumference 8 (8.75, 9.5, 10.25)" / 20.5 (22, 24, 26) cm
Finished sock circumference (unstretched stockinette): 8 (8.75, 9.5, 10.25)"
Foot length: adjustable — knit to 2" / 5 cm less than desired finished length before toe shaping notes (try on).
Leg length: adjustable — sample shown 6" / 15 cm from top of heel to bind-off.

Yarn: Worsted weight wool or wool-blend sock yarn, approx. 200 (220, 240, 260) yd / 183 (201, 219, 238) m per pair.
Sample: 100% superwash wool, 200 yd / 100 g.

Machine: Circular sock machine (CSM) with cylinder that accepts 44 (48, 52, 56) needles in work for the chosen size. Use the cylinder and needle gauge appropriate for worsted weight (commonly mid-gauge or bulky CSM setup). Ribber optional but not required (mock-rib or transferred 2×2 rib given).

Notions:

• Waste yarn (smooth cotton)
• Yarn needle for Kitchener stitch and ends
• Stitch markers or contrasting yarn scraps to mark side “seams”
• Standard CSM weights, heel forks/picks, transfer tools, and claw weights
• Tape measure

Gauge: 5.5 sts and 7.5 rounds = 1" / 2.5 cm in stockinette stitch on CSM (measure after knitting a swatch tube and washing).
Adjust cylinder, tension, or yarn until gauge is met. Gauge is critical for fit.

Abbreviations (US):
K = knit
P = purl
Rnd(s) = round(s)
St(s) = stitch(es)
SSK = slip, slip, knit (or machine equivalent decrease)
K2tog = knit 2 together
W&T = wrap & turn (for heel turn)
CSM = circular sock machine

Notes for Beginners on the CSM

• Always hang sufficient weight and move weights up often, especially at heel and gusset.
• Keep even cranking speed.
• “Needles in work” = selected cylinder needles with yarn.
• Half-cylinder = front (or back) half of needles for heel flap.
• Mark the two side needles (3 o’clock and 9 o’clock) with contrasting waste yarn or markers; these are your “side seams.”
• Try the sock on the recipient’s foot (or a sock blocker) before final cuff length and before closing the toe.
• All stitch counts are given for S (M, L, XL). Bold numbers are the working total after the instruction.

Pattern

Setup & Toe (Toe-Up Open Toe)

1. Using waste yarn, e-wrap or knit a foundation tube on 44 (48, 52, 56) needles for 8–10 rounds. Hang weights.
2. Join main yarn. Knit 1 plain round.
3. Begin toe increases (wedge/toe-up style):
   • Place markers on the two side needles.
   • Increase Round: On each side of both markers, make 1 stitch (lifted bar increase or machine equivalent — move adjacent stitch and fill empty needle). 4 sts increased per increase round.
   • Knit 1 plain round.
   • Repeat Increase Round + plain round until you have increased 8 times total → 44 + 32 = 76 wait — CORRECTED FINAL ONLY: for sock toes we increase from a smaller start.

Revised standard CSM toe-up open toe (final numbers):
Many beginners prefer starting on full cylinder and shaping a rounded toe later, but true toe-up open toe:

• Start with half the needles + a few: cast on with waste 22 (24, 26, 28) needles, knit tube, then transfer to full circumference while increasing.

Simple Beginner Toe-Up Method (recommended):

• E-wrap cast on 44 (48, 52, 56) needles with waste yarn. Knit 10 rounds waste.
• Join main yarn, knit 1 round.
• Work short-row toe (easier on CSM for beginners):
  Work back-and-forth on half the needles 22 (24, 26, 28) sts using heel springs or by putting opposite needles out of work.
  Short-row down: wrap & turn each side until 8 (8, 10, 10) center sts remain live.
  Short-row up: work wraps together as you return until all 22 (24, 26, 28) heel-half needles are back in work.
• Resume full circle. This creates a clean rounded toe. Total sts remain 44 (48, 52, 56).
  (Inline check: half = 22 (24, 26, 28); full cylinder restored ✓)

Cut waste yarn later and graft the open toe stitches with Kitchener stitch after the sock is complete (or close now if preferred).

Foot

Hang weights evenly.
Knit plain stockinette in the round on all 44 (48, 52, 56) needles until the tube measures approximately 4 (4.5, 5, 5.5)" / 10 (11.5, 12.5, 14) cm from tip of toe, or until the work reaches the front of the ankle when tried on (you will add gusset length next).
Place a removable marker or scrap yarn at each side needle to mark beginning of gusset.

Gusset

Increase for gusset on either side of the instep:
Gusset Increase Round: Increase 1 st on each side of the heel half (i.e., immediately before the first heel-half needle and immediately after the last heel-half needle). 2 sts increased.
Knit 1 plain round.
Repeat these 2 rounds 8 (8, 10, 10) more times → 2 sts × 9 (9, 11, 11) increase rounds = 18 (18, 22, 22) sts increased.
New total: 44 + 18 = 62 (48 + 18 = 66; 52 + 22 = 74; 56 + 22 = 78) sts.
(Inline validation: 9 × 2 = 18; 44 + 18 = 62 ✓; 48 + 18 = 66 ✓; 11 × 2 = 22; 52 + 22 = 74 ✓; 56 + 22 = 78 ✓)

Continue even (no more increases) until foot length from tip of toe measures desired total foot length minus 2" / 5 cm (the remaining length will be taken by heel turn and final fit). Typical adult foot lengths before heel: 7–9". Try on.

Heel Flap (worked back-and-forth on heel half)

1. Put the instep needles out of work (or raise them). You will work only on the heel-half needles plus the gusset stitches that belong to the heel side.
   Heel-half base = 22 (24, 26, 28) sts; remaining gusset sts are worked into the flap pickup later. For simplicity on CSM: work the flap across the original heel half 22 (24, 26, 28) needles, letting gusset sts sit on either side to be picked up.
2. Attach heel forks or use weights carefully on the flap section only.
3. Work heel flap back-and-forth in stockinette (or optional slip-stitch heel: sl 1, k 1 on right-side rows; purl back) for 22 (24, 26, 28) rows.
   End ready to turn heel on a right-side row.
   (Inline: flap rows = half-needle count for good proportion ✓)

Heel Turn (short-row)

Still on the 22 (24, 26, 28) heel needles:
Row 1 (RS): Knit to 2 sts past center, SSK, K1, W&T.
Row 2 (WS): Purl to 2 sts past center, P2tog, P1, W&T.
Row 3: Knit to 1 st before previous wrap, SSK (or work wrap tog with st), K1, W&T.
Row 4: Purl to 1 st before previous wrap, P2tog, P1, W&T.
Continue in this manner until all heel-flap stitches have been worked and 12 (14, 14, 16) sts remain live in the center of the heel.
(Inline target remaining: approx. half of flap + 1 or 2 for evenness; 12 (14, 14, 16) ✓)

Gusset Pickup & Decrease

1. Resume round knitting. Pick up and knit 11 (12, 13, 14) sts down the left side of the heel flap (one st per slip or edge row).
2. Knit across the instep needles (the ones held out of work).
3. Pick up and knit 11 (12, 13, 14) sts up the right side of the heel flap.
4. Knit across the remaining heel sts.

Total sts now: heel remaining 12 (14, 14, 16) + 2 × 11 (12, 13, 14) pickups + instep 22 (24, 26, 28) =
12 + 22 + 22 = 56 (14 + 24 + 24 = 62; 14 + 26 + 26 = 66; 16 + 28 + 28 = 72) — plus any residual gusset sts already on the machine from earlier increases.

Because gusset sts were already added earlier, the practical CSM method is:

• After heel turn, put all needles back in work.
• Knit one plain round, picking up the flap edge sts onto empty needles if needed so the total returns cleanly toward cylinder count.
• Then work Gusset Decrease Rounds:
  Decrease Round: On each side of the instep (or at the two side markers), K2tog (or SSK) to remove 1 st each side (2 sts decreased per round).
  Knit 1 plain round.
  Repeat Decrease Round + plain round until you are back to the original cylinder count 44 (48, 52, 56) sts.
  (Inline: decreases remove the extra 18 (18, 22, 22) gusset sts previously added — 9 (9, 11, 11) decrease rounds × 2 = 18 (18, 22, 22) ✓; final count 44 (48, 52, 56) ✓)

Leg

Knit plain stockinette in the round on 44 (48, 52, 56) needles until leg measures 5 (5.5, 6, 6.5)" / 12.5 (14, 15, 16.5) cm from top of heel, or desired length minus cuff.

Cuff

Work 2×2 rib for 1.5–2" / 4–5 cm:
K2, P2 around.
(On CSM without ribber: transfer every 3rd and 4th stitch to create mock 2×2 rib, or knit 1×1 mock rib if preferred. With ribber: set for 2×2.)

Bind off loosely in rib pattern using a stretchy bind-off (or sew bind-off / latched-off edge).
(Inline: 44/48/52/56 all divisible by 4 → perfect 2×2 rib ✓)

Finishing

1. Remove waste yarn from toe and graft the live toe stitches closed with Kitchener stitch for an invisible seam.
2. Weave in all ends securely on the wrong side.
3. Wash gently and block on sock blockers or dry flat to measurements.
4. Make second sock to match.

Fit Tips

• Too loose: go down a cylinder size or tighten tension.
• Too tight: larger cylinder or looser tension.
• Heel too deep/shallow: add or subtract 2 flap rows.
• Always keep weights moving — the #1 beginner cause of dropped stitches at gusset and heel.

Care: Machine wash gentle/cold if superwash; lay flat to dry. Non-superwash: hand wash, dry flat.

Enjoy your handmade CSM socks!