Stacy wrote and asked:
I was wondering if you could tell me how to figure out how to substitute yarns for different projects when you can’t find the yarn a pattern calls for.
the yarn they call for is 4 sts= 1″ #9
the yarn I would like is 20 sts=4″ #7So I wrote them down on a piece of paper and looked at them for a bit. Then I got out my calculator and looked at it. Then I remembered that I’m not so hot with math.
What kind of cruel joke is is that they don’t have standard gauges for these things? I’m sure it’s a conspiracy against me and me alone.
It is a conspiracy, but not against you alone. Like my Designers A and B who work for “Desperate Yarn Company”, pattern writers participate in an evil plot to get you to buy a particular yarn.
(Ok.. for those who don’t recognize irony in print, here is the non-irony version: It will turn out, the author, who runsMind’s Eye Yarn knit the cute easy hat for her friend, took the trouble to write it up and published it for free. Most people don’t write entire computer codes to let you imitate the shape with whatever yarn is on hand. I’m sure Stacy agrees. It’s a very nice pattern, and many of you will enjoy it.)
But getting back to the hat conversion, I wrote back and asked for more detail. What does Stacy want to knit? Turns out she wanted to convert directions for a warm ribbed hat.
So, what to do?
Well, for reasons of copyright, I won’t reproduce the whole pattern, but I will describe it and post the thumbnail to the right (which the courts seem to think is ok in some circumstances.):
0) The hat is knit in 4 x 4 rib. It has a fold up cuff and a moderately shaped crown.
The shaping isn’t “flat as a pancake beret”; it also isn’t “just knit straight then pull a string through.” It’s “in between.” (This observation matters when converting.)
1) You pick certain diameter needles and a certain legnth..
2) You cast on “N” stitches, which must be a multiple of 8 stitches because the hat is a 4 x 4 rib.
3) You join to knit circular, then knit 2 x 2 ribbing without shaping until the hat measures Llong; their “L” is 11 inches. (I advise checking if this fits your head while knitting.)
4) At that point, You shape the crown certain way which happens to require 11 rows. (To get the directions, you’ll need to read Mind’s Eye Yarn’s free hat pattern!)
5) You run a string through the stitches.
Easy!
As is often the case with simple free patterns, the directions are seems to be missing a few things. How big around is the hat etc.? What gauge are you supposed to get when knitting ribbing? Who knows?
Strangely enough, this stuff may be missing on purpose. Why? Because the exact dimensions don’t matter much for a ribbed hat: ribbing is stretchy. More importantly, specifying gauge in ribbing is difficult. Do you measure it stretched? Unstretched? People disagree, and various conflicting theories are correct in some sense. Chances are, if you follow the directions, and generally do hit gauge, the hat will fit. ( I advise trying on as you go.)
But, what about poor Stacy who can’t find the yarn they call for but found thinner yarn. If she just knits on the recommended needles, she’d get a thin wimpy fabric. Ick. If she picks smaller needles and follows the directions, her gauge will be smaller, and the hat will be to small. So, what to do?
Convert! (Oh, you’ll notice some of the conversion has practically nothing to do with math! That’s the hard part for some people. They think it’s all math; think the problem is they are stuck on the math, and then discover: It wasn’t the math!)
Ok, to begin, we need data:
- Stacy’s yarn has 5 st/inch = Stacy’s stitch gauge and recommends #7 needles.
- the pattern yarn calls for 4 st/inch = pattern stitch gauge and recommends #9 needles.
1) What size needles should Stacy use? Her yarn calls for two needle sizes smaller than their yarn. So, she should use two needle sizes smaller than the pattern says. Will this work? Well…. depends on if Stacy usually hits gauge. Regardless, this is the best first guess.
2) How many stitches should Stacy cast on? The original pattern suggested 88 stitches. Let’s call that N=88 stitches. To convert do this : N * “Stacy’s stitch gauge”/ “pattern stitch gauge”. This is 88 stitches * “5 st/inch” / “4 st/ inch” = 110 stitches.
However, 110 is not a multiple of 8. You can round up to 112 stitches or down to 104 stitches. I pick 112 stitches because that’s closer. (If you have a small head, pick 104 stitches.)
So, change the first direction to “Cast on 112 stitches.”
3) How long should the hat be before Stacy starts shaping? Believe it or not, we can’t calculate that yet! Well just say “Knit until length measures “L” and calculate “L” later. (Hint, the original length was 11 inches, the new one is 11.4 inches.)
4) How should Stacy shape the crown? Well, that depends. What does Stacy want to do? Here’s my thinking process: The tops of easy hats can be shaped all sorts of ways; unless the shaping is and precise as required for a beret, small variations in the shaping rate won’t be noticeable in the final hat. So, I say: Once she starts shaping, she should follow the directions exactly as written. (Note: no math involved! This is, in some ways, the hardest decision in coverting because you thinkhas to do with math, but it doesn’t. We could, however, make a design decision that would then require math. But we won’t!)
Ok, so no math. This means for Stacy’s first two rows, she should do this:
Row 1: K4, P2 tog, P2 around.
Row 2: K4, P3 around.
What’s happening? The hat has 4 x 4 ribs. Each “rib” is formed by 8 stitches: the 4 knit stitches stand out from the 4 purl stitches. Stacy is taking 1 stitch away each block “ribs”. Because she adjusted the number of stitches to 112 stitches, Stacy will decrease 12 stitches. The original pattern decreased 8 times during the first round.
What else will happen: Because she is removing 1 stitch from each rib, she will require 11 rows to finish, which happens when 2 out of the 8 stitches remain. How do I know this: 11 rows were required in the original pattern and she’s doing what they did.
Ok. But there must be some hidden problem, right? There are potentially two. The first doesn’t matter at all. The second barely matters.
Ok, notice Stacy is removing 12 stitches every 2 rows; the original pattern removed 8 stitches every two rows. This is somehow “different” right? Won’t it look different? It would for a beret. If this were a beret, she’d notice the hat got small to fast. She might see some rippling and gathering when she tries to block the hat.
If we were knitting a beret, we’d do math to address this.
But guess what? This is not a beret. A little gathering is ok. Some hats just knit straight, stop and draw a string through all the stitches; those have loads of gathering. So, in this case we want to do some “simple” shaping, that doesn’t destroy the appearance of the 4 x 4 rib, and doesn’t look too gathered. Following the written directions is fine.
Ok, but what about the other “potential problem”? Well, since Stacy’s stitch gauge is smaller than the pattern, her row gauge probably is smaller too, right? So, her 11 rows will be shorter than the original hat, right? That means the crown will be shorter. Because the crown adds to the hat length, the hat will be shorter. (Ok the shape will be a bit different too. Which means the truly math loving may point out that what I say next isn’t absolutely, positively precisely right.)
Is that a problem? Well, probably not.
But, because we here at “The Knitting Fiend” are anal about conversions, and Stacy may like the deep fold up brim, she should add some length. How much? Well….. 
To calculate that, we need to guess the row gauge of the pattern (which we aren’t told) and guess Stacy’s row gauge. How?
Well usually knit row gauges are between 1.3 and 1.5 times the stitch gauge. That is, if you get a stitch gauge of 4 st/inch, the row gauge is likely to be 5.3 rows per inch (that’s 4 * 1.3) to 6 rows/ inch (that’s 4 * 1.5). Of course, this depends on the stitch pattern. (If you knit garter stitch, the ratio is closer to 2 rows/stitch.)
Because the math is easier, we’ll pick 1.5 rows/inch. (Seriously. I’m not knitting a swatch for this. Anyway, you’ll see why soon.)
To convert: Estimate the length of the crown in the original pattern. Remember it has 11 rows, and we think the row gauge is 4 stitches/inch * 1.5 = 6 rows /inch
11 rows / 6 row/inch = 1.83 inches.
Next, estimate the length of the crown when Stacy uses thinner yarn. Remember, the hat still has 11 rows, but we think her row gauge is 5 stitches/inch * 1.5 = 7.5 rows/ inch
11 rows / 7.5 row/inch = 1.47 inches.
That means Stacy’s crown is 1.83-1.47 = 0.36 inches shorter. (Not much.)
So, as long as we bothered to calculate this we might as well adjust the instruction for the length.
The original length was 11.0 inches. The crown was 1.83 ” long. The whole hat was 11″ + 0.83″ = 11.83 inches long.
Stacy wants her hat to measure 11.83 inches right? But that’s “L” + 1.47 inches = 1.83″. So, L = 11.36 inches or 0.36″ longer than the pattern suggest. (I bet you already go here, right?)
At this point you round the way any marginally sane person would, and say:
3) “Knit until length measures 11.4 inches.
Then, when a truly sane knitter knits a simple hat, they would interpret the 11.4″ to mean 11.3″ or 11.4″ or 11.5″. (This is knitting right?)
You also ask yourself: Why did Lucia even show us how to convert this? It barely makes any difference. It’s a hat for heaven’s sake. In fact, when you fold that brim up, it makes a different of .2″ in the total length. I could have skipped the whole conversion, knit until the hat was 11″ and been done with it.
Lucia says, “Indeed!” As it happens, I showed you just incase you decide to substitute yarn that knits at 3 st/inch or 10 st/inch. This adjustment may matter in when you change gauge a lot. (BTW, If you are truly anal, you can look up the row gauges discover my factor of 1.5 should have been 1.3, redo the calculation, determine the “even better answer” for the length L is 11.42″ or something like that. Go ahead and knit until it’s 11.42″ long. Then, when you knit and realize you can’t measure 0.02″ you can fret and never finish your hat. If that happens, I’d recommend valium.)
Anyway, I think Stacy can knit her hat now!