I’m going to try the Fluidity pattern from Mary White that was posted in the FO section recently. She recommends using a lifeline. I can’t quite picture how to get the lifeline incorporated into my stitches. I plan to use white crochet cotton thread - is this a suitable choice? My yarn is a nice green color.
I did a lifeline once before, and used a different color of yarn. It was a disaster, it shed blue lint into my white stitches, and made that row lumpy and big… SO, I know what NOT to use.
That sounds perfect. It’s preferable to have a yarn that is a different color, lighter weight than the yarn you are using and not fuzzy.
There is a lifeline tutorial in the videos on the tips page. 
Ihave used narrow satin ribbon for lifelines–it doesn’t seem to stretch the stitches, and is so smooth it is easy to remove. linknit41
I’ve actually used dental floss as a lifeline. Very strong, and no shedding!
I have too, but I do recommend non waxed. It’s easier to take out when you need to.
And make sure the ends re long enough the come out on their own any lifeline you use. I make them long enough to tie together loosely.
First of all, 
for supporting my “design” habit and thanks!
I’ve found that a contrasting color from your project yarn is a must. And it MUST be smooth and colorfast…so I use a 5/2 weight (WEBS carries it) or a single strand of embroidery floss works perfectly. 5/2 is a tad bigger and twisted but embroidery floss is quite strong. Another suggestion is Quilting thread…VERY strong and super easy to find in sewing shops or departments.
Before I started using the interchangable needles, I’d thread a blunt needle with my lifeline and just below the circular needle filled with my project, starting at the round marker, go through each stitch all the way around, then, stretch out the project as much as possible or leave extra lifeline and knot, reknot and knot again. once you’ve passed that lifeline and are sure you’re on your way and have placed a second one, remove the first one. Unless you’re completely confident…place one at least once every 10 rounds and always on a knit round. Knit rounds are much easier to pick up if you have to rip out. And lifelines save major tinking. Hope this helps…
Mary, I’ve made it through the lasat round of the stitch pattern! It’s all good since I last contacted you. I’m so amazed at your ability to design and writ-out a pattern like that. I’m not sure how to see how big my project has become, since I can’t stretch it out to measure while still on the needles.
Wonderful! And I sent you a message on Ravelry…
If you put in a lifeline now, make it extra long, you can take it off the needles…the lifeline will replace your needles…really…trust me. Then you can stretch it out and measure it! WARNING!!! It is a bit tedious to place the needles back through the loops and you’ll need to be careful and count sts afterwards. Hope this helps!
Mary, I’m trying to avoid taking all 100’s of stitches off onto a lifeline just to measure the perimeter. Thinking about geometry. Would it be pretty safe to measure from the center out to the end of one corner - I figure it would be 25" for a blanket that is 36" on each side. What do you think? The exact measurements aren’t really critical here.
Not to the corner but from the center to a side, double it and you’ll have your diameter.
Oh, duh, and there I thought I had to do the Pythagorean Theorem, which I haven’t used since 9th grade!