Many machine knitters already knew this, so that may be why it was so hard for your extremely math-impaired author to find this information. It seemed to be top-secret, too, not to be shared with anybody, especially new machine knitters. Nevertheless, I have found it, and I know that other newbie MKers have wanted to know the same thing, so I am going to divulge this tasty bit of information, even if I end up in machine knitters jail for sharing it:
How in the world can I make a pattern written for one machine on a completely different gauge machine?
I know I wish I had known this, as I had wanted to make a pattern written for the 8mm Bond machine on my 9mm bulky. I sat there with a tape measure measuring the needles on the Bond and estimated how many stitches would be equal to that on my bulky. Oh, had I known how much easier that could have been! The project I made turned out, but probably more by sheer luck, rather than any skill on my part. Certainly not by mathematical precision.
Let’s say I have a pattern written for the bulky machine, but I want to make it on the standard or mid-gauge machine. How do I know how many stitches to cast on, bind off, decrease, increase, etc.? With an extremely easy formula:
Multiply the number of stitches for which the pattern calls by the gauge of the machine for which the pattern was written.
Divide that result by the gauge of the machine you wish to use.
This applies to all those numbers you find in the parentheses for different sizes in a pattern. You don’t need to calculate for every size, just the one you want.
For example, say we’re making a hat and the bulky pattern says to cast on 80 stitches. We would simply multiply 80 (the number of stitches in the written pattern) by 9 (the gauge of the machine for which the pattern was written). That gives us a result of 720. Now we divide that result of 720 by 4.5 (the gauge of the standard machine on which we wish to make the hat). We get a result of 160 stitches to cast on. 80x9=720. 720÷4.5=160.
You may be looking at that formula, and already know that the difference between the bulky and standard gauge machines is 2:1. After all, 4.5mm is half of 9mm. You would be correct. Now let’s say you wanted to make the same pattern on the 6.5mm mid-gauge machine. Easy enough! 80x9=720. 720÷6.5=110.77. Uh-oh. That didn’t come out even. In this case we would round up to 111 stitches. If you happen to have a 7mm mid-gauge machine, the formula is the same: 80x9=720. 720÷7=102.85, so you would casts on 103 stitches.
You would then also use this formula to calculate the number of rows to knit in any given pattern.
The reverse also works if you want to convert a pattern written for the standard gauge machine to a larger gauge machine: 160x4.5=720. 720÷9=80.
One caveat: Make sure you use this same formula to calculate the gauge of your swatch! Without this critical first step you will not know which tension setting to use on your machine! As with all projects, making a gauge swatch is always the first step in producing a well-fitting, and successful end result. For example: 17 stitches and 22 rows to 4 inches on the 8mm Bond would become 15 stitches and 19.5 (you can fudge up or down, depending on your yarn) rows to 4 inches on the 9mm bulky, or 30 stitches and 39 rows to 4 inches on the 4.5mm standard.
Hopefully this little tidbit of information will help out those new knitters that were asking this same question. I know it has opened up my collection of patterns because I can now make the same pattern on any one of my three different gauge machines! I am no longer limited to making it on the machine for which it was written!