I ♥ Pi!
As a thread crocheter who loves to make doilies and design in the round, I've come to love pi! I'm not a math person by any stretch of the imagination. If I have to do mental math I'm always off by a factor of 10. Designers all know that eventually it all gets back to the math when working a design.
Stitches per Diameter Inch (SPDI)
I was having a struggle with my very first design until I realized a very important equation concerning pi would help me tremendously. I call it stitches per diameter inch (SPDI), and is probably called by some other terms among other crochet designers and knitters.
To discover what your SPDI value is, work up a circle of dc stitches to 1" in diameter. Count the number of stitches. Example: On a size 1.25 mm hook with size 20 Lizbeth thread, 36 stitches = 1" diameter. Thus, my SPDI is 36 stitches. If I wanted to make a doily that is approximately 15" diameter, the last round would need about 540 stitches.
Knowing your SPDI is helpful if you are working with a different thread size than what a pattern calls for and want to know the final diameter of the doily with the smaller (or larger size) thread. (The math for that is a little more involved and I'll save that for another post.)
Stitches per Circumference Inch (SPCI)
This numeric value is important when making things to wear, like a necklace, hat, sock, sweater, etc. When I designed my first barefoot sandal I needed to know what is the average circumference of an adult woman's ankle. The average is about 11". Using the value of 36 stitches from above as an example:
36 ÷ 3.14 (value of pi) = 11.46 (sts per circumference inch)
Round up to 11.5 stitches per circumference inch: 11.5 x 11" = 126.5 dc stitches or thereabouts*
*When I crocheted up a swatch it took only 124 dc stitches.
Want to learn more about pi and Pi Day? Click here.
|What are your favorite types of pie?|
My other favorite use of pi was in the book Contact by Carl Sagan.
I also am very fond of pie. I'm very fond of cream cheese, key lime, blackberry pie, and beef shepard's. My least favorite pie is banana cream and steak and kidney.