Publish Time: 2026-10-22 Origin: Site
Interlock fabric is worn every day and understood by very few of the people who specify it. It looks like a heavier single jersey, behaves like a stable double knit, and gets quoted as if any double-bed machine could make it. That assumption produces the wrong gauge for the yarn, output forecasts copied from jersey speeds, and fabric that stops matching the sample once it is cut and washed.
An interlock knitting machine is a circular weft knitting machine with two needle beds, a vertical cylinder and a horizontal dial, in which alternating needles on each bed knit at alternate feeders so that two 1×1 rib structures are formed and locked into one reversible fabric. What defines the machine is the interlock gating: needles in the two beds face each other so that only one needle of a facing pair can knit at any feeder, and the pairs that knit together are diagonal rather than directly opposed.
This guide works backwards from the fabric to the settings that make it repeatable.
Interlock is a double-faced weft knit built from two 1×1 rib structures knitted from separate yarns and interlocked loop by loop, which is why both faces look the same, the cut edges do not curl, and the fabric cannot be unroved from the bottom edge.
The technical definition is compact: two 1×1 rib fabrics are knitted one after the other by separate yarns, which knit alternately on the face and back and are interlocked together, as described in textile engineering references indexed by ScienceDirect. The two ribs are joined by interlocking sinker loops rather than by bonding or lamination.
That construction explains most of what buyers care about. Both faces show fine vertical wales, so the fabric is reversible. Loop torque is balanced, so cut panels lie flat. Widthwise stretch stays low, usually 5 to 15 percent, while recovery is close to complete. At the same yarn count it is roughly twice as thick as single jersey, commonly 160 to 320 g/m², and the roll runs narrower than a rib because the structure pulls in as it relaxes.
Property | Single jersey | 1×1 rib | Interlock |
Needle beds | Cylinder only | Cylinder and dial | Cylinder and dial, interlock gating |
Face and back | Different | Identical rib | Identical, smooth |
Edge curl | Strong | Minimal | None |
Widthwise stretch | High | Highest | Low, 5 to 15 percent |
Common gauge | E20 to E32 | E14 to E24 | E18 to E32 |
Typical use | Basic tees, linings | Cuffs, collars, waistbands | Polos, leggings, underwear |
The resemblance to jersey disappears under tension: interlock holds its width, resists skew and keeps seams from grinning open. That is why it is treated as its own category within the wider family of double jersey circular knitting machine platforms.
The machine is built around two needle beds at right angles, independent cam systems for each bed, a sinker ring outside the cylinder, one yarn feeder per knitting point, and a take-down that pulls the tube away at constant tension.
The cylinder holds vertical latch needles in tricks cut around its circumference; the dial above it holds horizontal needles pointing outward. The beds are timed so that a cylinder needle and the dial needle directly opposite it never knit at the same feeder.
Gating makes this possible. Needles are set out alternately, one controlled from one cam system and the next from the other, and the needles that knit together are offset diagonally rather than facing each other, so each face becomes a complete 1×1 rib. An interlock machine therefore cannot be made by adding a dial to a jersey frame: the dial, its cams and the timing all assume the interlock sequence.
Component | Function | Effect on quality |
Cylinder and dial needles | Form loops on the two faces | Worn needles show as vertical lines in one wale |
Cylinder cam box | Clearing, stitch and guard cams | Stitch cam height sets loop length and weight |
Dial cam box | Tuck raising, knock-over, auxiliary knock-over, idle tracks | Timing faults cause holes and dropped stitches |
Sinkers | Hold loops down between needles | Poor setting distorts the face and the width |
Positive yarn feeders | Deliver yarn at a constant rate per feeder | Uneven delivery produces barré and weight variation |
Take-down and batching | Draw and wind the tube | Tension drift changes course density along the roll |
The dial cam box deserves the most attention during commissioning. Its auxiliary knock-over cam stops a dial needle from re-entering the old loop, a failure that is invisible on the machine and obvious as small holes in the greige roll.
The machine completes one full course using two feeders. At the first feeder one set of alternating needles knits while the opposite needles hold their loops, and at the second feeder the roles reverse, so the two loop layers interlock instead of lying side by side.
Rest. Needle heads sit within the knock-over edge, old loops held in the hooks.
Dial tuck. The dial needle advances and takes new yarn without casting off.
Cylinder tuck. The cylinder needle rises to a tuck position.
Dial clearing. The dial needle withdraws and the old loop clears the latch.
Cylinder clearing. The cylinder needle rises fully so its old loop clears.
Yarn presenting. Both beds move to where the feeder can lay yarn in the hooks.
Cast-on. Needles start to descend and the new yarn lands inside the hooks.
Knock-over. Old loops are cast off and new loops are drawn to stitch length.
The beds never occupy the same stage at the same feeder. The sequence interleaves, which is why interlock cam tracks are more complex than rib cams and why timing cannot be copied from one bed to the other.
If facing needles knitted at the same feeder, their loops would sit directly on top of one another and the layers would separate under tension. Interlock avoids this by selecting alternate needles on each bed and offsetting the two selections by one position. One course then needs two feeders, so a 108-feeder machine produces 54 interlock courses per revolution, thickness roughly doubles, and output per feeder stays below single jersey.
Cylinder diameter, gauge, feeder density, speed and take-down tension together determine weight, width, surface quality and hourly output, and changing one almost always forces a change in another.
Parameter | Typical range | What it controls |
Cylinder diameter | 14 to 40 inches | Tube circumference and needle count |
Gauge | E18 to E32, commonly E20 to E28 | Stitch density, yarn range, hand feel |
Feeder density | 1.6 to 3.2 per inch of diameter | Courses per revolution and output |
Speed factor | 700 to 850 (rpm times diameter) | Throughput against yarn stress and wear |
Gauge | Typical yarn | Resulting weight | Character |
E18 to E20 | Ne 16/1 to Ne 20/1 | 240 to 320 g/m² | Firm and opaque, suits kidswear and uniforms |
E20 to E24 | Ne 20/1 to Ne 30/1 | 180 to 240 g/m² | Mainstream range for polos and leggings |
E24 to E28 | Ne 30/1 to Ne 40/1 | 160 to 200 g/m² | Smoother, better drape, harder to run |
E28 to E32 | Ne 40/1 and finer | 140 to 180 g/m² | Fine-gauge knits, tight yarn tolerance |
Weight is a comfort decision as much as a cost decision. Research comparing interlock with other knit structures, published in Textiles, found interlock the most compact and mechanically stable of those tested, and confirmed that density and porosity govern breathability and moisture transport. The matching logic is set out in this guide to circular knitting machine gauge.
Output follows the same logic. A 34 inch, 24 gauge machine with 108 feeders at 25 rpm and 85 percent efficiency knits roughly 20 kg per hour of 250 g/m² interlock, and the figure checks out: 54 courses per revolution, about 3 cm of fabric per turn, roughly 18 courses per centimetre. Real output falls below the rating because of yarn breaks, doffing, needle changes and restart settling time.
These machines supply the structured, opaque end of the knit market, where shape retention and a clean double face matter more than drape or high stretch.
Polos and heavier T-shirts needing a smooth surface and opacity without pique texture.
Leggings, base layers and underwear that need coverage and recovery rather than high elongation.
Childrenswear, because the doubled structure resists push-through and holds shape through washing.
Mattress ticking, cushion covers and uniform fabrics, where stability reduces sewing problems.
Structure | How it is made | Typical end use |
Single pique | Knit and tuck at alternate feeders | Polos with a textured face |
Cross tuck | Tuck selection offset across courses | Small relief patterns |
Ponte di Roma | Interlock and plain courses alternated | Dresses, suiting, structured leggings |
Eight-lock | Knit and miss selection on the dial | Firm double-faced fabrics |
Ottoman rib | Miss courses forming horizontal ridges | Outerwear and trims |
Mills running single jersey and double jersey machines often develop these qualities on the double jersey frame first, then move successful ones to a dedicated interlock machine once volume justifies it. Interlock is a poor fit for swimwear and compression wear, for sheer lightweight fabrics, and for multicolour jacquard work.
An interlock knitting machine forms fabric from yarn. An overlock machine trims and encases cut edges. An interlock sewing machine, also called a coverstitch machine, joins and hems with a stretchable cover stitch. The three sit at different stages of production and are not alternatives to one another.
Machine | Stage | What it does | Typical operation |
Interlock knitting machine | Fabric formation | Knits two interlocked 1×1 rib faces | Producing interlock rolls for cutting |
Overlock machine | Joining and edge finishing | Trims the seam allowance and wraps the edge with two to five threads | Side seams, shoulder joins, sleeve setting |
Interlock sewing machine | Hemming and topstitching | Two or three needles with a looper underneath | T-shirt hems, cuffs, elastic attachment |
The collision causes real sourcing errors: a request for an interlock machine may return a quotation for a sewing unit, and a request for a coverstitch machine may return knitting equipment. Disambiguate by specification, since a knitting machine is described by diameter, gauge and feeder count, and a sewing machine by needle and thread count.
An interlock circular knitting machine justifies its capital cost when a mill runs recurring interlock volume, needs tight control over weight and width, and has technicians who can keep two needle beds synchronized. When demand is seasonal or the mix changes weekly, commission knitting is usually cheaper.
Cost element | What to budget for | Why it matters |
Machine and frame | Tubular, open-width or high-frame build | Frame choice affects finishing and roll handling |
Needles, sinkers, cams | Around 5 to 10 percent of machine cost per year | Double-bed machines use two needle sets |
Power and air | Motor load plus cleaning air | Continuous running makes energy a line item |
Technical labour | One experienced mechanic per several machines | Cam timing cannot be improvised |
A simple payback test frames the decision. Multiply expected annual kilograms by the gap between outsourced and in-house conversion cost, then compare that saving with annual ownership cost, including depreciation, spares, power and labour. If the saving covers ownership in under three years and the order book is stable, the investment holds; volumes that are small, irregular or constantly changing usually favour outsourcing. The same logic applies to any industrial knitting machine purchase, though interlock sets a higher technical bar because two beds must stay synchronized.
Most interlock problems trace back to four causes: worn or bent needles, cam timing that has drifted, lint packed into the dial, and uneven yarn tension across feeders.
Defect | Likely cause | First check |
Vertical line in one wale | Bent needle or wrong needle in the trick | Needle condition at that position |
Small holes in a diagonal pattern | Late or early dial knock-over | Dial cam timing and auxiliary knock-over |
Horizontal banding | Uneven feeder tension, mixed yarn lots | Feeder tension and lot segregation |
Width variation along the roll | Take-down tension drift | Tension settings and batching consistency |
The preventive habits are unglamorous. Blow down the dial, cam boxes and sinker area every shift. Inspect needles under light weekly rather than waiting for a visible line. Record stitch length and finished weight at every quality change, so drift is caught on the machine instead of in the roll.
Can one interlock machine also knit rib and single jersey?
It can knit rib and many double jersey variations by changing cams and needle selection, but not true single jersey, which needs only one needle bed. Mills run rib on the same frame when gauge and diameter suit both, and keep jersey on a dedicated machine.
What yarn count and fabric weight suit interlock?
Combed cotton from Ne 20/1 to Ne 40/1 covers most production, with Ne 30/1 the middle ground on E20 to E24 machines. Standard weights fall between 160 and 320 g/m². Lighter fabric needs finer gauge and better yarn; heavier fabric comes from coarser gauge, longer stitch length or plied yarn.
Can interlock be knitted on a flat bed machine?
Yes. Double-system V-bed flat machines can produce interlock and its derivatives and are useful for sampling and small panel runs. Commercial yardage is almost entirely circular, because a flat bed knits one panel at a time and needs two carriage traverses per course, making it far slower per kilogram.
WELLKNIT was founded in Taiwan since 1987, and in 1995, we set up the production base in Quanzhou, Fujian, is the first Taiwan-funded weft knitting machine manufacturer to take root in Quanzhou.