Combining tuck stitches with lace 2 (automating them)

Working with 2 carriages when both are selecting needles brings up some interesting issues. Studio machines are able in most instances to select and knit in the same row. Brother preselects needles for the subsequent row, and on that row, while knitting the preselection, once again, the preselection is made for the next pattern row to be knit.

A couple of my earlier posts on the topic: knitting with 2 carriages and a lace round doily which combines lace with slip stitch selection to emulate holding for creating the needed spiral.

Following up on the previous post, now attempting to automate the stitch, some of the logic in needle selection needs to be explored. The chart as drawn below simply addresses functions that may create the desired fabric. It is incorrect in terms of accuracy in actual knitting it

theory

 symbols used

theory symbols

reworking the repeat for use with mylar

mylar selection

 the drawn mylar repeat, numbers reflect placement on my sheet

mylar repeat

mylar symbols2

When both carriages are in use for pattern selection, they will both engage the belt. While either carriage is in use, the alternate one needs to be off the needle bed, or the belt may actually break as one carriage holds it in a fixed position, while the other tugs at it toward the fixed spot from the opposite side of the machine. Lace extension rails are used on both sides. There were variations over the years, including a pair to fit the bulky 260 KM. They are not always exchangeable between models, need to sit properly on the machine for carriages to be stable while stored to the side, and also for moving them off and onto the machine easily.

Pre-punched standard Brother lace cards usually begin with the lace carriage selecting the first pattern row moving from the left side to the right. As with any lace or tuck fabric, knitting begins with waste yarn that is weighted evenly and any edge treatment of choice. On the 910, because of the preselection factor, and to keep the pattern continuous in proper order, the knit carriage is removed from the right side of the machine, and the lace carriage does a preselection row from right to left. That will be its start and return position for the remainder of the fabric. The knit carriage is returned in turn to its home on the right end of the machine, on the extension rail.

Two types of fabric are being created. The goal is to have the edge stitches knitting throughout. To accomplish this, if the LC is in use, eliminate any end needle selection by pushing needles back to B; when the KC is in use, if the end needle is not selected, to get it to knit, it needs to be pushed out to E. The pattern sequence is an easy one when up and running, with 2 passes of the LC, and 4 of the KC, as seen in the charts above.

The knit side is shown below, the arrow locating the larger eyelet points to operator error: I had a stitch caught on a gate peg, and was not aware of the problem for several rows. The extra loop of yarn can actually be seen. Tuck fabrics are often far more interesting on the purl than on the knit side

mylar_knit1

the purl side, with an arrow indicating the same problem spot

mylar_purl1

The question that follows is how to program the same design for use with a punchcard machine. Here things get a bit more confusing. The electronic machines advance the program or card a single row for each carriage pass, no matter their direction or sequence. When the punchcard carriage is at rest on either side and the alternate carriage moves toward it, the card does not advance, so the needle selection stays the same, is repeated for a second time. A bit more planning is required and the repeat needs to be shortened to accommodate for this fact.

The chart below shows the amended repeat for punching a card. The first selection row is made with the card locked, and the LC moving from left to right. The card is then released, LC moves to the left, transferring stitches selected from the previous row to the left while selecting those for the first row of tuck. The next row, using the alternate carriage, begins the ongoing sequence

punchcard chartA

the actions of the carriages with each pass

what carriages do

The actual punched holes are shown below. The writing on the card is a ghost from a previous experiment. The red line marks starting row 1 for Brother knitting, blue border outlines a single repeat. A minimum of 3 repeats are needed for continuous reading by the KM

punchcardFabrics with color change every 2 rows such as mazes and mosaics are easily knit on the electronic with 2 carriages. If worked on a punchcard machine, they would have to be executed using a yarn changer and only the knit carriage, unless the design motif is redrawn to factor in the issue discussed above. A previous post, part of a thread on mazes and mosaics, with a punchcard swatch photo.

The first preselection row in any patterning that involves color or carriage changes every 2 rows, is usually done toward the side of the machine that holds either the color changer or the carriage next in use. As seen above, there are exceptions to that “rule” as well.

Large scale mesh, breaking rules

The goal is to produce a large-scale mesh without hand techniques or extra steps.
In both slip and tuck, every punched hole, black square in mylar, or pixel in electronic downloads that bring a needle out to D position (for some unfathomable reason Brother needle positions go A, B, D, E, poor C got skipped) will result in a knit stitch. In the slip setting the non selected needles get skipped creating floats, while in the tuck setting, the non selected needles will hold a loop in the needle hook until that needle is returned to the D position. Side-by-side loops are troublesome in any stitch type. That said, tuck can be employed to sequentially lay down loops in some patterns where the lace carriage moves to produce side by side empty needles as part of the planned design.

The usual caution with such fabrics: extension rails must be used since both carriages engage the belt. The yarn needs to be “friendly” enough to not break easily. Since stitches travel across a wider gap than in single eyelet lace, the tension needs to be looser as well. Small changes can make a big difference, and so can patience. If end stitches are selected prior to the lace carriage making the next row of transfers, push them back to B manually so as not to produce decreases or dropped stitches.
Working the punchcard on a punchcard machine:

The lace carriage is set for normal lace, preselects the first row of knitting with the punchcard not locked on its first pass to the right. The KH carriage is set on KC I with both tuck buttons depressed. Each carriage works in sequences of 4 passes throughout.
Actions performed by the carriages as they make their next pass to the opposite side:
Lace carriage 

COL: moves to the right with no preselection
COR: no transfers, preselects for transfers to the right
COL: transfers to the right, preselects transfers to the left
COR: transfers to the left, preselects for the first tuck row. There will be 3 single needles with 3 stitches on each of them and two empty needles on each side
Knit carriage:
COR: knits first tuck row, makes the same preselection
COL: knits second tuck row, preselect the next tuck row, on a different needle position
COR: knits third tuck row, in the alternate location, preselects for all knit row
COL: knits all stitches, preselects blank row

Some observations: the top bind off as seen in the swatch below, was tight for the fabric. To maximize its width, the bind-off should be around at least 2 gate pegs, even 3 if needed. This allows for completing the task on the machine without adding more work and adding hand techniques. Tuck stitch produces a knit that tends to be short and wide, lace wants to open up with blocking as well, so this fabric definitely will want to spread. The top approximate 1/3 of the swatch below was kit using the same white yarn but in standard single needle mesh, making the size difference in “holes” created with the tuck method easy to see. The white is a 2/8 wool, the other a 16/2 mystery fiber I usually use as waste yarn.

For me this experiment will probably fall in the “now that I’ve done it, broken several rules, and have a good result I am over it” category.

 

The wonders of blocking

Blocking is one of those knitting preferences that can arouse strong pro/con arguments, and goes the range from casual to nearly compulsive with wires, pins, and assorted tools used to achieve desired results. My shawls continue to sell well: the photos below illustrate part of the process and 2 of the most recent in their family. All shaping and joining are achieved through the knitting process; the shawls are reversible, may be worn and draped in a  variety of ways.

before steaming and pressing

unblocked1

detail shot after steaming/pressing

blocked1

one way to wear, purl side facing out

shawl1