(I get the horrendously clever name for this pattern from my grandmother, who used the phrase "your mother is going to crown you" to tell me I was in Big Trouble.) This will be available as a free .pdf download on Ravelry (as soon as I figure out how to do that), but I know not everyone is Raveled around here, so here's another, more chatty version, with commentary on needle felting.
So. The prototype:
And the version I knit to make sure the pattern worked:
I tried to make this as idiot-proof as possible, because let's be honest. I suck at felting.
SIZE: whatever. You tailor to your intended victim.
MATERIALS: Approximately 100 yards/90 meters of worsted-weight wool. Doesn't much matter what. The purple version shown here was knit with Brown Sheep Lamb's Pride Worsted and the yellow one was knit with worsted-weight Highland Wool from Elann.com. Remember, superwash wool won't felt. I know, I state the obvious, but I've had a few... issues in the past. See above about how I suck at felting.
Some wool bits, embroidery thread, or sundries for decoration are also needed, unless you want a bare crown (which is certainly more dignified for a head of state). I used some corriedale roving I had laying around.
NEEDLE SIZE: Doesn't really matter. I used 10.5 US/6.5 mm needles. Generally wool felts better if it's knit loosely, I suspect so the fibers can rub together during the felting process.
GAUGE: Doesn't matter. Told you it's foolproof, or nearly.
PATTERN NOTES: For increases I used 'make one' (backward loop over the needle where needed), and for decreasing I used 'knit two together'. Doesn't really matter what you use, though. THIS PATTERN IS WORKED IN STOCKINETTE.
Cast on 12 stitches using any method you like. This includes selvedge stitches; I slip the stitch at the beginning of each row. Working back and forth in stockinette, work a couple inches/maybe 6 cm.
On a right side row, *knit across row; two stitches before edge (one active stitch and the selvedge stitch) make one, knit rest of row. Purl the next row. Repeat from *, making one stitch at the end of each right side row until you have 24 stitches. (That's 24 rows.) Make sure your selvedge stitches are very loose on the increase side of the strip.
On the next right side row, *knit across to last three stitches, knit two together, knit one (the knit one is the selvedge stitch). Purl next row. Repeat from * until you have 12 stitches again. (Another 24 rows.)
You have now made a peak. Make two more, the same way. (If you were making, say, the spinal ridge for a dragon costume, you could extend this indefinitely. Food for thought.)
At the end of the third peak, knit another couple inches/maybe 6 cm. Bind off any way you like. You will now have something that looks like this:
That's my foot in there for scale.
Get over your urge to kill me, and chuck your knitted strip into the washing machine. I ran both these crowns on the heavy-duty cycle for 15 minutes, small load, hot/cold wash temp. A swish of soap but nothing major. When it comes out, it should look like this:
Lay it out flat and leave it to dry.
FINISHING: Get out a tape measure and measure the head of your intended victim one last time. Remember to measure around their head where/how they intend to wear the crown; mine were made to be worn on the back of the head, more like a hat, because they're for small children and that's how little kids wear everything. For an adult, measure higher up on the head, and in a line parallel to the floor, if your adult intends to wear this like a real crown.
My measurement came out to 22 inches/56 cm. (Hey. The kid's got a big head and lots of hair.) Divide your figure in half; in this case 11 inches/28 cm. Then, WORKING FROM THE CENTER OF THE STRIP OF KNITTING which is marked by the center of the second peak, measure out in either direction.
What you're doing is making sure that you are cutting a centered hunk out of the strip; you don't want the peaks of your crown being lopsided. By working out eleven inches from each side of the center peak, I got a 22 inch long strip that is centered properly. It also means the cut ends will match up (close enough) for sewing.
Butt the ends together and overstitch or whip-stitch them together. You can use thread or leftover yarn; I used thread on both. It will likely look like a bad suture on Frankenstein's monster. It's a toy. Chill.
If you have more faith in your mad knitting skillz than I do, you could felt a swatch, then knit the crown as a single piece, grafting the ends together, and felt it. You could then skip the sewing step and the visible seam. Up to you; I destroy nearly everything I felt, so I used the less knitterly but more foolproof cut-and-seam method.
DECORATION: Really, the sky is the limit on this one, though weight is a factor; the peaks of the crown will droop if you hang anything too heavy off them. You can still put that heavy stuff around the band at the bottom.
I used needle felting, because I had a bag of bad roving hanging around from a spinning project gone wrong, and some felting needles I'd bought for no apparent reason. If you've never done needle felting, this is a fine project to start on because you really can't go wrong. Craft stores are now selling 'learn to felt' kits with small bags of roving and a couple felting needles for less than ten bucks USD, so it's probably cost-effective, in comparison to buying plastic jewels or buttons to glue or sew on.
Anyway. I'd pull off a small wad of roving.
Then I'd coil it loosely into a circular 'jewel' shape. Flat circle. (Oval would work too, or octagon or something, if you actually have needle felting skill.)
Work your way carefully around the outside of the shape, gently nudging the roving where you want it. Then once the shape is established, go Norman Bates on it and stab the daylights out of it, all over, until it's stable and flattish with no loops sticking out.
And you have a jewel on a felt crown. The possibilities are endless. Knock yourself out.