Converting Weights & Measures between Yarns

[MickiD]

I am thinking of switching the yarn to be used from that provided in the pattern to another yarn that I've worked with and like the way it handles as crocheting and the way the final product lays.  Pattern is lace shell/pullover top and yarn given in pattern is 3 oz/251 yds skein.  Both the pattern yarn and the yarn I would rather use ("Preferred Yarn") are Light/3 but the Preferred Yarn is only 1.75 oz/136 yds skein.  When figuring the no. of skeins required for the Preferred Yard, is it more important to go by the weight of the skein (9 skeins instead of 5) or the no. of yards (10 skeins instead of 5)?  I've made a couple of things that have turned out well enough to wear them a time or two and I'm getting better as I go but rather than spend a lot of time on something for a time or two, I would like to make this one a wardrobe staple so any help sorting this out on the front end will be appreciated.  Thanks.

[nancybanta]

If the wraps per inch is the same for both yarns - wrap each yarn loosely around a ruler for one inch then count how many times each goes around - then you need to go by the yardage.  Just by weight/yardage calculations, your "preferred yarn" is slightly thinner than the yarn the pattern calls for.  Make a swatch from each and compare.  If you're comfortable that the size of the finished item will be the same then use what you want.