What is Float Stitch or Loop?
The float stitch which is also called a ‘miss’ or ‘welt’ stitch is a variation of the basic loop structure. It is created in the fabric when a needle is inactive. The previous loop is held within the hook, the yarn fed from the yarn carrier fails to reach the needle and so skips over it.
A float stitch is composed of a held loop, one or more float loops and knitted loops (see in Figure 1). It is produced when a needle (M) holding its old loop fails to receive the new yarn that passes, as a float loop, to the back of the needle and to the reverse side of the resultant stitch, joining together the two nearest needle loops knitted from it.
In Figure 2, the float stitch shows the missed yarn floating freely on the reverse side of the held loop. (This is the technical back of single-jersey structures but is the inside of rib and interlock structures.) The float extends from the base of one knitted or tucked loop to the next, and is notated either as an empty square or as a bypassed point. It is assumed that the held loop extends into the courses above until a knitted loop is indicated in that wale.
A single float stitch has the appearance of a U-shape on the reverse of the stitch. Structures incorporating float stitches tend to exhibit faint horizontal lines. Float stitch fabrics are narrower than equivalent all-knit fabrics because the wales are drawn closer together by the floats, thus reducing width-wise elasticity and improving fabric stability.
Loop Formation of a Float Stitch:
The following series of diagrams show the forming procedure of a miss or float stitch.
- Only two of the needles ascend to clearing position and clear the latches. The needle in the center fails to ascend and remains in the lower position while holding onto its loop.
- The yarn carrier travels across the machine feeding new yarn into the hooks of the active needles.
- Active needles descend to knockover and form new loops. The needle in the center creates the “miss” effect by retaining its loop. The connecting yarn between the newly formed loops simply passes behind it. The elongated loop formation is called a “held” loop.
Properties and Uses of the Float Or Miss Stitch:
The practice of missing certain needles during the knitting procedure is widely used in the flat knitting trade. The various uses and the loop properties exploited are:
1. Knitting plain knits: When the raising cams of one needle bed are completely withdrawn to miss all the needles, the machine knits with the other needle bed only. It produces a plain knit structure, as illustrated in all notation system in the following figure 4. The missing procedure can be carried out on the front needle bed so the rear needle bed is active (a) or on the rear needle bed leaving the front active (b). The blank squares in the English and German systems are the inactive (missing) needles of the inactive needle beds.
2. Knitting a variety of rib structures: Besides the 1×1 rib, all other rib structures require some of the needles to miss. The 2×2 (in German 2:1) in the following figure 5 (a) is the most popular rib structure for garments elasticated welts. As can be observed from the illustration, in each needle bed two needles are active and one misses. In another rib structure shown in the figure (b), the combination of active and missing needles is different.
3. Improvement of the fabric’s widthwise stability: A missed loop, creates a short connection between two adjacent wales and eliminates the accordion effect of the rib. Straight segments of yarn formed in the fabric, ensure that the stretchability of the structure is reduced. The result is a much more stable construction.
4. Decrease of fabric width: Short connections between the wales, as shown in the previous paragraph, affect the fabric width. A large number of miss stitches in a course reduces the fabric width considerably.
5. The production of jacquard structures: The main use of miss stitches, in a selected fashion, is for the creation of jacquard fabrics.
6. The use of the structural deformation: The structural deformation resulting from a missing sequence can be used as a patterning effect on the fabric. The miss stitches have to be arranged according to a predetermined design to create such a pattern. To increase the size and boldness of the deformation, the missing sequence can be repeated as shown in the following figure. The same needle is missed for two consecutive courses, the held loop is stretched even more and the deformation is greater.
7. Marking of garments: The different appearance of the missed loop can be used for the marking of cutting lines. Arm holes or a “V” neck lines can be defined the on garments, during the knitting process. On longer production lines, garments can be code marked in a hidden place to allow machine recognition and trouble shooting during later production processes.
What is Tuck Stitch or Loop?
The tuck stitches are the knitted structures in which certain loops are intermeshed with elements of two kinds: tuck loop and held loops. Tuck stitches can be weft and warp knitted, and are produced on machines equipped with any known types of needles.
A tuck stitch is composed of a held loop, one or more tuck loops and knitted loops. It is produced when a needle holding its loop also receives the new loop, which becomes a tuck loop because it is not intermeshed through the old loop but is tucked in behind it on the reverse side of the stitch (Figure 6). Its side limbs are therefore not restricted at their feet by the head of an old loop, so they can open outwards towards the two adjoining needle loops formed in the same course. The tuck loop thus assumes an inverted V or U-shaped configuration. The yarn passes from the sinker loops to the head that is intermeshed with the new loop of a course above it, so that the head of the tuck is on the reverse of the stitch.
In analysis, a tuck stitch is identified by the fact that its head is released as a hump shape immediately the needle loop above it is withdrawn, whereas a knitted loop would require to be separately withdrawn and a miss stitch would always be floating freely on the technical back.
The tuck loop configuration can be produced by two different knitting sequences:
- By commencing knitting on a previously empty needle. As the needle was previously empty, there will be no loop in the wale to restrict the feet of the first loop to be knitted and, in fact, even the second loop tends to be wider than normal. The effect is clearly visible in the starting course of a welt. By introducing rib needles on a selective basis, an open-work pattern may be produced on a plain knit base.
- By holding the old loop and then accumulating one or more new loops in the needle hook. Each new loop becomes a tuck loop as it and the held loop are knocked-over together at a later knitting cycle and a new loop is intermeshed with them. This is the standard method of producing a tuck stitch in weft knitting.
Tuck Stitch Formation:
In the series of following diagrams, the forming procedure of a tuck stitch is shown. The different steps in the sequence are:
- The previously formed loop is in the hook of the needle which now starts to ascend.
- The needle’s ascent is stopped short of clearing position with the loop still placed on the needles latch.
- A new yarn is fed into the descending needle. Since the new yarn is not pulled through the previous loop, it does not acquire a loop shape. Instead, it is simply placed in the hooks enclosure together with the previous loop. The adjacent needles have formed new loops during this sequence, so the previous loop held by the tucking needle is now stretched and deformed.
- The needle now ascends to clearing position and both previous loop and tucked yarn drop under the latch.
- The descending needle is fed with a yarn. The previous loop together with the tucked yarn slide under the latch, close it and slide over the hook.
- The new yarn is pulled into knockover position and forms a new loop. Note that the tucked yarn is hooked between the two knitted loops.
Properties and Use of the Tuck Stitch:
Tuck stitches are widely used in the production of V-bed flat knitted garments as well as in the production of cut and sew knit wear from circular knitting machine. They are used for the following reasons:
1. Fabric patterning: The different appearance of the tuck stitch, in comparison with the regular standard loop background, can be used for patterning. The stretched elongated held loop relaxes on leaving the knitting zone, forming a small buckle on the face of the fabric. When tuck stitches are arranged on the garment according to a plan, a design is formed. This however requires a needle selection system on the knitting machine.
2. Increasing fabric weight and thickness: The tuck yarn is added to the standard loop without a knitting sequence and no new loop is produced. A large number of tuck stitches can thus add to the weight and thickness of the fabric.
3. Increasing fabric width: The principle described above also shows why fabric width increases as a result of a large number of tucks. This increase is caused by the presence of more yarn in the structure, and the restrictive forces applied by the tuck courses to the tendency of the rib to contract.
4. Insertion of problematic yarns: Not all yarns are able to be formed into the shape of a loop due to their mechanical properties. With tucking procedures, such yarns can inserted into the fabric with only a mm1mum of bending stresses shows in the following figure. Note that while the central needle tucks, the rest of the needles miss. The fabric does not advance and the loop of the tucking needle is not stretched.
5. Shortening of jacquard floats: Long floats can be formed on the reverse side of the fabric as a result of a jacquard patterning sequence. These floats can easily be pulled by such objects as a ring or a wrist watch, resulting in loop distortion on the fabric face and damage to the garment. To reduce the size of such floats, lessening the danger of snagging, tucks can be introduced along the float.
6. Garment marking: The different appearance of the tuck stitch, in comparison with the standard loop background, can be used to mark cutting lines in the garment during the knitting process. Furthermore, the knitting machine can code mark the garment in an obscure place to allow machine identification for quality control during later production stages.
References:
- Knitting Technology, 3rd edition by David J Spencer
- Understanding Textile for A Merchandiser by Shah Alimuzzaman Belal
- Reference Book for Knitting By Carmine Mazza and Paola Zonda
- Fundamentals and Advances in Knitting Technology by Sadhan C. Ray
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Founder & Editor of Textile Learner. He is a Textile Consultant, Blogger & Entrepreneur. Mr. Kiron is working as a textile consultant in several local and international companies. He is also a contributor of Wikipedia.
