Why use double yard to knit a project ?

[knity]

I'm trying to understand the reasoning about this. I have seen several patterns that are to be made with double yarn out of DK or sport weight yarn. I don't understand why you would do this rather than just use a heavier yarn. Does anyone know the answer ?? Thanks in advance for all your help.

[suzeeq]

With older patterns, the thicker yarn might not have been available, or maybe because of the type of yarn. You could try worsted or bulky yarn instead, as long as the gauge tension works out right.

[ARiley]

Or maybe for an effect with color or texture, depending on the pattern.

[suzeeq]

That's true, a smooth yarn with a bumpy, furry, or eyelash yarn, two colors. Is there a pattern in particular you're wondering about?

[knity]

The one pattern, I saw it on, was not old, it was a vest made with alpaca DK weight, and the other was in a book, which I am not sure of the age, but it looked like a light weight summer sweater, then when you read, it was made with a double yarn DK weight. Just sort of didn't make sense. I know the vest when made up, you could not tell it was made with two strands.

So, other than a certain texture or color, it sounds like I could just use a heavier weight yarn and only one strand. Thanks

[Yarnlady]

It also may be they were trying to sell a certain yarn and it only comes in DK weight. If you have to double it then they sell twice as much yarn....

[suzeeq]

A DK yarn doesn't necessarily mean you knit with it double stranded, that's just the weight which is between sport and worsted.