Design Process Part V: Compute

Time to crunch some numbers. The schematics are for one side only. Double the numbers for full waist and full bust measurements.

FYI - I did the schematics in Microsoft PowerPoint through a series of lines and shapes. It seemed to work out nicely. I saved them in JPG format when I was done.

We need to go back to our gauge swatches and review our numbers.

* Ribbing Gauge: Stretched 6 sts and 8 rows = 1"
* Stockinette Gauge: 5 sts and 6 rows = 1"

BACK



Step 1: Determine Stitch Count for Cast On
How many stitches do I need for my cast on? Since I am starting from the bottom, let's take a closer look at the waist measurement and the gauge swatch for the ribbing. My waist measurement is 29". The stitch gauge for the slightly stretched ribbing is 6 sts = 1".

29" x 6 sts/inch = 174 sts

But wait...my ribbing pattern is of the 3x2 variety, which means my CO stitch count needs to be a multiple of 5 sts, so it is perfectly neat and orderly all the way around. I bump up my stitch count to 175 sts.

Step 2: Decrease Stitch Count for Change to Stockinette
After knitting 4" of ribbing, where the dotted line represents the true waist line, we change to stockinette stitch. If I kept the CO 175 sts constant, all of a sudden my garment would not be as fitted. My stockinette stitch gauge is 5 sts per inch. At 175 sts, that would mean 35" around my waist (175 divided by 5). That would be huge on me.

This means I will need to decrease my stitch count where I change from ribbing to stockinette. Using my 29" waist measurement and my stockinette stitch gauge (5 sts = 1"), the numbers of sts I need at the waist in stockinette will be:

29" x 5 sts/inch = 145 sts

But wait...I need an even number of stitches to make the back and front have the same number of stitches. Thus, I subtract 5 sts to give myself some negative ease. 140 total stitches. 70 sts for the front. 70 sts for the back.

Going back to Step 1 where my stitch count is 175. I need to decrease 35 sts evenly over 175 stitches to get myself to 140.

175 divided by 35 = 5 stitches.

My pattern will be k3, k2tog. Which is to say, every 5 st grouping, decrease 1 st. Repeat.

Step 3: Shape Sides
I need to go from my waist measurement (29") to my bust measurement (35") over 6 inches. I decreased my actual bust measurement by 1/2" for some negative ease.

Yes,I know what I said before about the ease. I changed my mind due to the advice of honeybee. She recommended some negative ease. Thanks honeybee!

35" x 5 sts/inch = 175 176 sts. Once again, I need an even amount of sts to make the front and back the same.

I need go from 140 to 176 stitches over 6" (as indicated in the schematic). My stockinette row gauge is 6 rows = 1" which means I need to increase 36 sts over 36 rows. How nice and neat is that? It would be great to just increase once per row. However, I would like the increases to be done equally at the sides.

I will be increasing 4 sts every 4th row 9 times, with the 4 sts being divided equally at the 2 sides of the garment. I'll probably need stitch markers to keep myself organized.

You might have noticed that I am not really going to have 176 sts at the bust due to the low back. That is okay as the increases still need to be determined as if it were the case.

Step 4: Shape Armholes and Shoulders

I measured the armhole depth of a well=fitting tank and determined that 1.5" is a good number.

1.5"x 5 sts/inch = 7.5 8 sts

I'll BO 5 sts, then decrease 1, 1, 1 sts on subsequent rows to achieve the curve.

I decided my shoulders going to be 1" (5 sts) before the trim.

8 sts for armhole depth + 5 sts for shoulders = 13 sts each side at the bust line in the back

Step 5: Shape Low Back
You might be wondering why I didn't do this step prior to the armhole and shoulder shaping. I had to reverse engineer my shaping for the low back. You'll see in a minute.

A u-shaped neckline is achieved by binding off 1/3 of your stitches and gradually decreasing each side.

70 sts divided by 3 = 23 sts (left side) + 24 sts (center) + 23 sts (right side)

Just working one side... we have 23 sts at the bottom of the deep U.

I am increasing at the sides in Step (3). It will be +9 sts for one side.

23 + 9 = 32 stitches

In order for me to get to 13 sts from Step 4, I need to decrease 19 sts for the low back. It's going to be decrease 5, 4, 3, 2, 1, 1, 1, 1, 1 sts every other row for each side. That will take 18 rows to get those decreases in. That's 3" according to our row gauge.

I bring this up to describe the low back curvature. It will decrease upwards from the center BO for 3". This hits to about mid-back on me. Then it will rise up vertically to the shoulders.

FRONT



Step 6: Shape Bust Darts
I am 7.5" from bust point to bust point. According to my references, you don't want the darts to be right on top of bust points. Makes sense to me. So we add 1.5" to the measurement, making it 9". 9" = 45 sts for the center. We need to round this up to 46 sts because we want the darts on either side to be over the same number of sts.

Now to calculate the number of sts on either side:

* 88 sts total at the bust - 46 sts for center stitches = 42 sts
* 42 sts divided by 2 = 21 sts for each side

Now we have to determine the depth of the bust dart. Sources tell me that 1" - 1.5" is usually good for bust dart depth. I'm not that big at top - a small B. I decide up on 1".

Using the row gauge information, 1" = 6 rows. We need 6 short rows to create the 1" bust dart. Bust darts are a series of steps on either side, so we divide 6 by 2 and there are 3 steps on each side.

21 sts for each side divided by 3 = 7 sts

Starting at the armhole shaping, the bust dart instructions will be:

* Knit to last 7 sts. Wrap & turn.
* Purl to last 7 sts. Wrap & turn.
* Knit to last 7 sts. Wrap & turn.
* Purl to last 7 sts. Wrap & turn.
* Knit to last 7 sts. Wrap & turn.
* Purl to last 7 sts. Wrap & turn.
* Knit across, picking up wraps to end.
* Purl across, Picking up wraps to end.

Step 7: Shape Front Neck
To create a crew neck, you are suppose to BO 1/3 of the sts in the center and decrease from there.

The number of stitches I have between the shoulders is 62 sts. I'll BO 20 sts in the center. And then I need to decrease 21 sts for each side.

The best way for me to visual how to do the shaping was to chart it out. I used standard graph paper, but you can use knitter's graph paper. In knitting, since the number of rows is greater that number of sts per 1 inch, knitter's graph paper will give you a better depiction of how something is going to look. By physically drawing out the desired curvature, I can see how many stitches to decrease at each row.

Post Number Crunching
That's everything, I think. Everything should be in order. We'll see once the knitting begins.

Upcoming: Design Process Part VI: Cast On!