What is heavy worsted weight?

I have a pattern that calls for heavy worsted weight yarn. I am hoping to substitute a knitpicks yarn but I don’t know what is comparable.
Thanks

The only one that I know of that KnitPicks has marked as Heavy Worsted is the Shamrock. What other people have actually experienced may be different. I haven’t used too many of their yarns yet.

Thanks. Is it possible to combine two yarns to make a heavy worsted? If so what is a good combo?

http://www.knitpicks.com/content/index.php/archive/yarn-weights/

What’s the actual gauge on your pattern? You could probably substitute a lot of different yarns if it is a pretty standard gauge (like 18 st/ 4in). You could even use a regular worsted yarn and use bigger needles to get the gauge. You could definitely hold two yarns together to get gauge as well…it would just take some experimenting.

If you wanted to use 2 strands together, possibly 2 sport weight would work. 2 DK might, but it could be a little too thick, depending on the actual yarn. KPs calls their merino style DK, but it’s more like a light worsted, so 2 strands of that would be equal to bulky yarn.