Having only knitted simple things like scarves and the ABC blocks where the size isn’t all that important, I’ve never bothered to knit a tension swatch before. However, now that I’m planning to knit my first jumper I’ve gone and done it.
These swatches are cast on using the long tail method and bound off traditionally. I didn’t want to waste the yarn so didn’t bother to cut it after each swatch.
They all look extremely similar in size because the tension was only ever off by the tiniest amount and I thought that the next needle size down would be enough. The pattern I am working off calls for size 10 and 12 needles, with the swatch measured using the size 10. I knew that I’d need different sizes because I’m using a different weight yarn to the one in the pattern, but I still did the first swatch using the size 10. The next is on 11 and the final one, which matches the gauge perfectly, is on 12.
Finally, because the pattern calls for 2 needles and the sizes I will be using have now changed I had to figure out what the other size should be. It would have been so easy to fall for the trap in thinking that I could just move down the same number of sizes, ergo 12 and 14 to replace 10 and 12. Luckily, last year when I was exploring the world of yarn substitution I came across the fantastic Knitting Brain site and their free calculators. This is such a wonderful, easy and helpful tool – now I know the best possible needle to use and it is definitely not the 14! According to the calculations, I should be using a needle that is 2.33mm. Since there is no such needle, I will be using the size 13 (2.25mm) as it’s closer in size than the 12 (2.75mm). Also, I shouldn’t use the same size needle when the pattern calls for two different ones.
Hope this works out…