Interlock / Coverstitch comparison
JACK K7-UT vs JACK W4: which interlock / coverstitch machine should you buy?
A side-by-side look at two interlock / coverstitch machines from our catalog: the specifications each one lists, where they differ, and which kind of production each suits. Both are used for knitwear, activewear, garments.
JACK K7-UT
Jack’s current cylinder-bed interlock, replacing the older K6 — an AI chip reads fabric thickness in real time and adapts automatically, from heavy to light fabric.
JACK W4
Cylinder-bed interlock machine (W4-D-01GB) with a 3-needle/5-thread setup, a 0.65–1.3 differential ratio for gathering or stretching seams, and a max speed of 5500 s.p.m.
Key differences
- JACK K7-UT lists the higher top speed: 6000 s.p.m. against 5500 s.p.m.
- JACK K7-UT lists an automatic thread trimmer; JACK W4 does not list one.
- Availability: JACK K7-UT — Order on request; JACK W4 — Order on request. Call to confirm today's stock.
Specifications side by side
| Specification | JACK K7-UT | JACK W4 |
|---|---|---|
| Series | Interlock (cylinder-bed), AI-integrated | — |
| Max sewing speed | 6000 s.p.m. | — |
| Transport torque | 9.2Nm | — |
| Controls | Touch screen with voice guide | — |
| Feed | Active Feed system, auto thread trimmer | — |
| Build | Rhombic arm, 20mm edge-to-foot clearance; nano-ceramic thread guides | — |
| Vibration / noise | Reduced vibration and noise vs. previous generation | — |
| Best for | T-shirts, underwear, jeans, mid-to-high-level clothing | — |
| Availability | Order on request | Order on request |
| Model shown | — | W4-D-01GB |
| Needle | — | UY128GAS, 11-14# |
| Needle no. / thread no. | — | 3 / 5 |
| Stitch length | — | 1.5–4.5mm |
| Stitch width | — | 5.6 / 6.4mm |
| Differential ratio | — | 0.65–1.3 |
| Max speed | — | 5500 s.p.m. |
| Weight | — | 48–64 kg (model-dependent) |
Highlighted rows differ. A dash means the catalog does not list that specification for the machine; ask us and we will confirm it.
Which one fits your work?
Choose the JACK K7-UT if…
Jack’s current cylinder-bed interlock, replacing the older K6 — an AI chip reads fabric thickness in real time and adapts automatically, from heavy to light fabric.
- Adapts to fabric thickness
- 20mm clearance rhombic arm
- 9.2Nm transport torque
Choose the JACK W4 if…
Cylinder-bed interlock machine (W4-D-01GB) with a 3-needle/5-thread setup, a 0.65–1.3 differential ratio for gathering or stretching seams, and a max speed of 5500 s.p.m.
- 0.65-1.3 differential feed
- 3-needle / 5-thread seam
- Runs up to 5500 s.p.m.
Swami Enterprises is an authorized JACK dealer and importer. Bring your own fabric to the Chanakya Place showroom and sew on both before you decide.
Questions buyers ask
What is the difference between the JACK K7-UT and the JACK W4?
JACK K7-UT lists the higher top speed: 6000 s.p.m. against 5500 s.p.m. JACK K7-UT lists an automatic thread trimmer; JACK W4 does not list one. Availability: JACK K7-UT — Order on request; JACK W4 — Order on request. Call to confirm today's stock.
Which is better, the JACK K7-UT or the JACK W4?
It depends on your fabric, operation and daily volume. The JACK K7-UT is described as: Jack’s current cylinder-bed interlock, replacing the older K6 — an AI chip reads fabric thickness in real time and adapts automatically, from heavy to light fabric. The JACK W4 is described as: Cylinder-bed interlock machine (W4-D-01GB) with a 3-needle/5-thread setup, a 0.65–1.3 differential ratio for gathering or stretching seams, and a max speed of 5500 s.p.m.
What is the price of the JACK K7-UT and the JACK W4?
Prices depend on the model, quantity and the day. Call +91 99713 36656 or request a quote for today's price on either machine.
Can I see both machines before buying?
Yes. Visit the showroom at Chanakya Place, New Delhi. Call +91 99713 36656 first so the team can confirm which models are on display and in stock.
Not sure which to pick?
Tell us your fabric, operation and daily volume. A specialist will recommend one, with today's price.