Most likely that is to get a ‘bulky’ weight. That’s not an exact science though since each weight can have varying gauges. Probably works most of the time.
Secondly, I have now discovered, with the help of an online chart, that your worsted weight is our aran weight, which requires 5.5 mm - 6.5 mm needles, so why is the pattern saying to use a doubke strand of this and knit it with a size 5 mm needle?
Worsted weight is generally 18-20 stitches per inch. The two terms aran and worsted are generally used interchangeably. I think some consider aran just slightly heavier, but not bulky. The lower end (18) of worsted.
Incidentally, I think my gauge has shrunk. It used to be quite loose, but now I can get 5 stitches to an inch on what I assume to be worsted weight yarn, slightly less on the doubled up double knitting yarn.
Your gauge can vary with what mood you’re in (angry, frustrated or, relaxed and happy) how long you’ve been knitting (10 minutes vs 3 hrs for instance) as well as the needle type (wood vs metal), knitting style (english vs continental) as well as yarn weight to needle size. So many reasons. This is one reason to do a swatch, but people often say “swatches lie” and the reason are all of the above.
This is the first time I knew that you guys used the term double knitting when referring to yarn weights - one area where we speak the same language lol.
Yep! And I think jinxedone was right when she said if your yarn was DK the slippers would be too small.
SO… the lesson here is to use the correct weight yarn and gauge and then do a swatch to find the needle size that works with the pattern gauge. That should work to get close to the correct slipper size.
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