A little while ago, a friend of mine had a birthday. I was excited about making something for her, so I whipped up a pair of my short-row felted slippers.
My friend wears a size 10 shoe, but I thought it would not be a problem. I worked my instructions exactly as I had written them, with a size 13 needle, and the same yarn. The slippers should have been somewhat larger, right?
No. The new pair of slippers were exactly the same size as the original. There are probably at least two lessons in that.
1) Knitting on a deadline (like a birthday) always invites disaster.
2) When your knitting needle is already over 1/3 of an inch thick, going up by one needle size may not make a lot of difference in the final work.
What to do? Lucky for me, I have a patient friend. She not only accepted my offer of "future" slippers, she lent me a pair of store-bought slippers that fit her well, so that I could measure them.
I did and found that her slipper's sole measured about 4.25 inches wide and 11 inches long.
I already had a gauge for the slippers, but instead of doing math to see what I should do, I measured directly off of my own slippers, which are aging pretty well. This gave me more confidence in what was needed.
I decided that the needed 2 inches of slipper length should come from 5 more garter-stitch ridges (or stitches, depending on which part of the slipper we mean) and that the width of the original slipper was just perfect. I added 3 of the ridges (or stitches) in the toe and 2 in the heel, to make it generally even, but I prefer a slipper that comes up a bit higher on the foot, so that it will stay on better.
I used #13 needles and the same yarn as before. It still only used 4 balls of yarn.
The final slippers came out very well, and I'm including the instructions with this post. They're called "Angie's Slippers", after my friend.
This method could be extended, really, to just about any size of slipper. The main thing to remember is keeping track of how far up the foot the top of the slipper will reach.
Also, I have reservations about extending the size by a lot more. I worry that the sole of the slipper may become too floppy if worked at a truly large size. Or maybe I'm just being odd about it. Perhaps the underlying structure of the top of the slipper is enough to keep the back of the sole in line. Or maybe the larger sole should be worked in 4 strands of yarn instead of 2. I don't know yet.
If you have a slipper size you would like me to write a version of this pattern in, drop me a line at firstname.lastname@example.org with the desired width of the toe, width of the heel, and length of the foot, and I'll try it.
This is the direct link to the pattern for Angie's Short-Row Slippers.