Old crot thread sizes

[Kathryn Walker]

I recently acquired some vintage patterns that call for Puritan crochet cotton Article 40 thread. Does anyone know what size that is or where I can find out?

[Granny Square]

Welcome to the 'ville!  I make a lot of doilies, and mostly vintage patterns (but I don't necessarily pay attention to what size thread they say to use, I mostly use size 10 thread and a steel hook size 7 or so).

This is entirely off the top of my head, but I think Puritan Article 10 is size 10.  What size hook does it say to use?  What are you making?  In other words, if it's a doily or a decorative item, if it's an inch bigger or smaller it's not a big deal, but if you are making a wearable it's a different story.

The Ravelry editor that entered that thread into the database (see link) is 'guessing' size 10, and from the photo I'd agree that looks reasonable; also I believe 'bedspread cotton' implies that size as well.

Very rough yardstick also off the top of my head, a size 6-8 steel hook called out in a pattern probably means #10 mercerized cotton, 8-10 steel hook #20 thread, and hook size 12 or so #30 thread.  I have seen some some patterns ~1940 calling out different  doily sizes using 10, 20, and 30 thread sizes and appropriately sized hooks following the same pattern. 

Here is a blogger's rough wraps per inch test for mercerized crochet thread.

 

Edited February 10, 2022 by Granny Square

[Granny Square]

Another site,  on wraps per inch for crochet cotton.  When I do a WPI test, usually for yarn, I wrap it directly around the ruler, 1 inch 'in' from the edge (in other words, wrap over inch #2 on the ruler, so you're not wrapping at the edge and having loops potentially falling off.)

 

Edited February 10, 2022 by Granny Square

[Bailey4]

Once you do figure out the size you want Creative Yarn Source does carry the smaller sized threads up to 60.  The colors are more limited above size 30 but they still do carry them.  They have great customer service if you contact them about size color needs as well.

[IgorsJoy]

This article talks about a substitute for Puritan Article 40:

https://millvillestitchers.com/puritan-crochet-cotton-article-40-substitute/