1. ADVANTAGES AND DISADVANTAGES OF A LOCKSTITCH TYPE 301 AND
A DOUBLE THREAD CHAIN STITCH TYPE 401
LOCKSTITCH TYPE 301
STITCH STRUCTURE
FEATURES OF THREADS INTERLACING
It can be seen from the stitch structure that the top thread «А» and the bottom thread «В» should be
interlacing in the middle of the material, while one branch of the bottom thread «В» passes through the loop
of the top thread «А».
ADVANTAGES
1. The upper and lower sides of the stitch have the same appearance.
2. Low threads consumption per stitch.
3. The stitch seam is difficult to ravel if the threads in the stitch are interlacing in the middle of the material.
4. The upper and lower sides of the stitch are more resistant to abrasion.
DISADVANTAGES
1. Due to the low consumption of threads per stitch, the stitch seam stretches less.
2. It is necessary to precisely adjust the tension of threads to ensure that the threads are interlacing in the
middle of the material.
3. To sew with a stitch, it is necessary to change the bobbin with the bottom thread often.
DOUBLE THREAD CHAIN STITCH TYPE 401
STITCH STRUCTURE
FEATURES OF THREADS INTERLACING
It can be seen from the stitch structure that the top thread «А» and the bottom thread «В» are interlacing in
the lower surface of the material, while first the loop of the bottom thread «В» passes through the loop of the
top thread «А», then vice versa, the loop of the top thread «А» passes through the loop of the bottom thread
«В».
ADVANTAGES
1. Due to the higher threads consumption per stitch than for a lockstitch type 301, the stitch seam is stretched
more than the stitch seam of lockstitch type 301.
2. To form a stitch, all threads are fed from a large coil.
3. The stitch seam join the materials is more tear-resistant than the stitch seam of lockstitch type 301.
DISADVANTAGES
1. The upper and lower sides of the stitch have different appearance, the lower side of the stitch is very similar
to the chain.
2. The interlacing of threads on the lower surface of the material creates a thickening, so the underside of the
stitch is less resistant to abrasion.
3. A relatively large threads consumption per stitch than for a lockstitch type 301.
4. The stitch seam easily unraveling from the end, this disadvantage can be eliminated by securely tacking the
end of the seam.
5. The stitch seam easily unraveling from the place where the stitch is skipped, towards the beginning of the
seam, this disadvantage can be eliminated if sewing is guaranteed without a single stitch skipping.
INVENTOR: PhD. Zarif Sharifovich Tadjibaev, Director of ZARIF SEWING MACHINE CO., LTD.
Web.: ZARIF.UZ / YouTube Channel: youtube.com/@ZarifTadjibaev