Originally Posted by Anemone
Generally, you can change the size/weight of your yarn or thread and it will just change the gage & size of your finished piece. But especially with finer work, if you change it too much, your work will curl or wave. With crochet cotton, the higher the number, the finer the thread. 50 is quite fine - size 10 is four sizes larger (since the sizes go 10, 20, 30, 40, 50 etc. 100) as far as I know. Though 10 & 20 are the most commonly found these days, the others are available. I know that DMC does make a size 50 thread in their cordonnet line and it is available from online stores. Try your pattern with a size 20 thread if you have it in your stash, but I would order a ball or two of the size 50 and go ahead & try it.
Thank you so much for explaining this for me!!!!!!
I don't know much about vintage patterns or even gages. I think I have one or two of balls of sz 20 and sz 30. I'll around for the sz 50.
PS: what is the best sz hook for sz 10, 20 & 30?