Engineering ActiveSeam

Building a new class of stitching

The development of ActiveSeam occurred over four years. Challenged to create a perfectly flat seam that would replace Flatlock, the team at Merrow worked from 2008 until 2012 to refine and develop the ActiveSeam class of stitches. The program was a collaboration between Merrow's engineering team, sewing team and machine building team. The process continues today, with new developments and mechanical breakthroughs changing the ActiveSeam stitch every day.

After years of work Merrow produced ActiveSeam; a NEW class of stitch that is Flat, Comfortable, Beautiful, Durable and designed for performance apparel.

ActiveSeam Performance Advantages: The Seam is almost undetectable when applied next to skin! With more stretch built into the seam, the garment can be designed to fit the human body better without restricting athletic movement. When compared to a flatlock stitched seam (4 needle 6 thread, ISO 607) with identical thread, fabric, and SPI, both ActiveSeam 2 & 3-thread seams proved to be more than 30% stronger and had the ability to stretch (linear travel) 100% further.


  • Seam Type: ActiveSeam
  • Threads: 2/3
  • License Type: Territory/Category
  • Merrow: USA
  • Branded / Trademarked Stitch: Yes

The ActiveSeam Class of Stitches:

Make ActiveSeam™ Part of Your DNA

ActiveSeam Infused 3D


The signature version of Activeseam allows a designer to add depth and color to a garment.

ActiveSeam Comfort


A two thread seam, the Comfort stitch is designed to be soft on the skin. A Comfort seam may be used on everything from Yoga clothing to delicate lingerie.

ActiveSeam Slim


The two thread Slim ActiveSeam presents both a new design option as well as a comfortable alternative to simple overlock seaming. For apparel that require discrete detail, the Slim ActiveSeam is the perfect choice.

Intelligent Seam Variation

Building the right VERSION of the Seam into Performance Apparel

Be Innovative
Be First
Be Distinct
Be Sexy
Be Bold
Be Creative
Be Comfortable
Be Technical
Be Amazing
Be New
Be Free
Be Durable

An New Class of Seams with nearly Infinite Variation

Make ActiveSeam™ Part of Your DNA



An ActiveSeam setup on the Merrow MB-4DFO allows for 900 configurations of stitch density
Needle Plates

Needle Plates

A stitch is defined by it's width and depth. With more than 30 needle plates available for ActiveSeam, the stitch is transformed, product by product with the Needle Plates
Feed Dogs

Feed Dogs

Material handling is controlled by the Feed Dogs. With many different styles available for ActiveSeam machines, the delicate issue of ensuring that fabric passes through the machine perfectly is no problem.

The Merrow Stitch Lab in Fall River, MA - The Art & Science of ActiveSeam

lab and machine