EZ as pi

Ugh.

Ever have one of those days?

Why are these things so flimsy?  Am I suppose to buy new headphones when this happens?  Order replacement covers, only to have them rip again?  And from where?

Being ever the pragmatic one I thought I could do better if I just made them myself.  It sounded good in my head.  I searched Ravelry for patterns and found only crocheted ones.  I could crochet, but...hmm, think. All I had to do was knit a circle...and when it's big enough, stop.  But how many stitches do I start with?  And when do I increase?  Well, EZ, that's Elizabeth Zimmermann, had the answers, and I provided a few of my own.

EZ as pi Headphone Covers

Materials:
leftover sock yarn, you really don't need much. 
2 hair bands
1 set of dpn's size US 1 (or whatever method you use to knit in the round)

Cast on 9 stitches using Emily Ocker's Circular Beginning (if you don't have Knitter's Almanac by Elizabeth Zimmermann, shame on you, both the pi shawl, from which this pattern is heavily borrowed, and this cast on is described in that book)

Round 1 knit.
Round 2 (increase row) knit into the front and back of each stitch, 18 stitches
Knit 3 rounds
Round 6 (increase row) see Round 2, 36 sts
Knit 6 rounds
Round 13 (increase row, do you see a pattern here?)
Knit until it's big enough (I did 3 more rounds, if you need to knit more than 12 rounds, you'll have to do another increase row).

Cast off over a hair band, like this:

That is, holding the hair band behind your knitting, when casting off alternate pulling the yarn through the inside (make a stitch, cast it off) then over the outside of the hair band (make a stitch, cast it off) thus wrapping your cast off around it.  I know! I thought of that all by myself!

Here's a youtube video of the cast off -- sorry no audio, I'll work on that.