PATTERN:

For my project I’m actually using this vintage pattern published on KnitHeaven: http://www.knitheaven.com/vintagepatterns/image_322.htm
(the pattern on the webpage is slightly different from the Kneecap by Needlecraft Publishing Co. pattern)

EDIT:
The pattern I’m using is originally from Beeton’s Book of Needlework by Beeton Isabella, 1870, which can be found for free here:

http://www.antiquepatternlibrary.org/pub/PDF/BeetonNeedle...
(see 322.--Knee-cap in Knitting.)

http://beetonsbookofneedlework.com/page_309.htm#image_322

http://beetonsbookofneedlework.com/

NOTES:

• changed from DPNS to short circular (30cm), which made it so much easier to knit! ..no more dropped stitches. The gore is knitted on DPNS because it’s worked back and forth.
• 2/2 ribbing, and 2x2 check pattern (2k-2p over 2 rows, then switch) for the gore
• 35 rows bottom and top of the gore --> EDIT: try 47.
• Gore insert: starts on front (26 stitches at the centre), augments picking up 1 stitch/side from the ribbed part at each row, until 42 sts remain of the ribbed part; then decrease back (symmetrical to augment). --> EDIT: reduce the gore to 1/2 or 1/3.
• Then go back to circular needle and knitting rib 2/2.

I finished the first cap: it’s quite large and the gore is enormous! --> reknit with the following changes:

• a much smaller gore (half or even a third)
• reduce the number of stitches casted on to 100

Even with the reduced stitch count, the fit is still not very good because the knee gore is fairly pronounced and would only fit ok on someone who only sits down (when you stand, the gore would pucker outwards and not be nice).
This is going to be frogged.