{"id":354686,"date":"2026-09-13T22:56:03","date_gmt":"2026-09-13T17:26:03","guid":{"rendered":"https:\/\/stitchpartner.com\/?p=354686"},"modified":"2026-09-13T22:56:03","modified_gmt":"2026-09-13T17:26:03","slug":"interlock-flatlock-sewing-machine-guide","status":"publish","type":"post","link":"https:\/\/stitchpartner.com\/hi\/interlock-flatlock-sewing-machine-guide\/","title":{"rendered":"Interlock vs Flatlock Sewing Machines: Complete Guide"},"content":{"rendered":"

Quick Answer<\/h2>\n

An interlock machine and a flatlock machine are often talked about as one thing \u2014 “flatlock (interlock) machine” \u2014 because most flatbed machines that produce a flatlock seam are built on the same platform as machines that produce interlock\/coverstitch seams, just set up differently. The short version: interlock stitching covers and hems knit fabric with rows of parallel stitching, while flatlock stitching joins two fabric edges into one very flat seam with no raised allowance. Which one you need depends on what you’re sewing \u2014 T-shirt hems and coverstitch work call for interlock setups, while activewear, innerwear, and sportswear side seams call for flatlock.<\/p>\n

What Is an Interlock Sewing Machine?<\/h2>\n

An interlock machine \u2014 also called a coverstitch machine \u2014 sews two or three parallel rows of straight stitching on top of the fabric with a looper thread woven underneath. This is the stitch you see on the hem of almost every T-shirt, on sleeve cuffs, and anywhere elastic or binding is attached to knitwear. It stretches with the fabric instead of popping stitches, which is exactly what a hem on stretch fabric needs.<\/p>\n

Interlock machines typically run 2 or 3 needles with 1 or 2 loopers, and are a flatbed design \u2014 the fabric feeds flat under the needles rather than around a free arm.<\/p>\n

What Is a Flatlock Sewing Machine?<\/h2>\n

A flatlock machine joins two separate fabric edges into a single seam that lies almost completely flat, with no raised seam allowance poking out on either side. That flatness is the entire point \u2014 it’s why flatlock seams show up on activewear, innerwear, sportswear, and compression garments, anywhere a raised seam would rub or show through thin fabric.<\/p>\n

Mechanically, a flatlock machine is usually the same platform as an interlock\/coverstitch machine \u2014 the difference is in how the fabric is fed and folded through it, not a completely different machine. This is exactly why you’ll see the same Pegasus or Kansai Special model described as both an “interlock” and a “flatlock” machine depending on how it’s set up.<\/p>\n

Interlock vs Flatlock vs Overlock: Quick Comparison<\/h2>\n\n\n\n\n\n\n\n
\u092e\u0936\u0940\u0928<\/th>\nWhat It Does<\/th>\nTypical Use<\/th>\n<\/tr>\n<\/thead>\n
Interlock \/ Coverstitch<\/td>\nParallel top stitching with looper coverage underneath<\/td>\nT-shirt hems, sleeve cuffs, attaching elastic\/binding<\/td>\n<\/tr>\n
Flatlock<\/td>\nJoins two edges into one flat, low-profile seam<\/td>\nActivewear, innerwear, sportswear side seams<\/td>\n<\/tr>\n
Overlock (Serger)<\/td>\nTrims and wraps thread around a raw edge to stop fraying<\/td>\nSeam finishing, edge neatening on wovens and knits<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

If you’re buying your first machine for a knitwear or garment unit, most factories eventually need all three \u2014 but if you can only add one right now, match it to your actual product: hemming-heavy work (T-shirts, kidswear) needs interlock first, activewear\/innerwear needs flatlock first, and general stitching needs overlock first.<\/p>\n

Popular Interlock\/Flatlock Machines in India<\/h2>\n

The Pegasus W500 and W562 (and the newer W600\/W664 series) are among the most common flatbed interlock\/flatlock machines running in Indian garment units, alongside Kansai Special’s DFB and DLR flatbed ranges. JACK also makes a dedicated interlock\/flatlock machine, the W4 series, built as a direct-drive alternative to the Pegasus and Kansai platforms. Whichever brand you’re on, parts availability matters more than the badge on the machine \u2014 Pegasus and Kansai Special models in particular have been in Indian factories for decades, so genuine-spec spare parts are widely stocked.<\/p>\n

Keeping an Interlock\/Flatlock Machine Running Well<\/h2>\n