This is a pattern for making a mitten with a flat fold thumb on a circular sock machine.

You can use any cylinder/yarn combination that gives you a tube that will fit snuggly but comfortably over your hand. For my average woman’s hand, I’ve had good results on both a 54 cylinder and a 60 cylinder with fingering weight yarn. To make mittens for larger hands, try using DK weight yarn on a 54 or 60 cylinder, or maybe heavy fingering weight yarn on a 72 cylinder.

Note that the left hand and right hand mittens are different, be aware that the thumb flap instructions tell you which needles to leave in work depending on which mitten (hand) you are doing.

Also note that in addition to Kitchenering the top of mitten closed, there is some handwork required to sew up the side of the thumb. It’s helpful if you know how to mattress stitch two knitted edges together. There are YouTube videos that will show you how to do that, one link is included in the pattern.

For rehanging the held stitches after the thumb flap is cranked, I used two 6” size 0 double point needles.

Amount of yarn used in my samples:
Cascade Heritage Sock (439yds/100g): a little under 50g
Koigu KPPPM (175yds/50g): a little over 50g, (you can omit a few rows of the cuffs if you use a thicker yarn like Koigu and have a 50g skein)