A 36 Gauge Crown Felting Needle is mostly used for inserting fibres into vinyl dolls heads or very fine work. A Crown Needle does not have barbs the length of their spine. Instead, the Crown Felting Needle has a single row towards the tip, in a "crown" formation. This means that they are more suited to very fine work, as they can only grab a few fibres at a time.
Needle felting is a process of using barbed needles to interlock wool fibres to form a more condensed and tight material. Wool fibers have scales which when needled against each other catch and lock into place to create this denser material called felt. Felting needles are used to entangle the fibres. As the felting needle is moved up and down, the barbs on the needles catch the scales of the wool and entangle them into place.
There are many sizes of needles that are available to use for needle felting. The most popular are the 36, 38 and 40 triangular and star sided needles. The 36 gauge triangular pointed needle is the most commonly used for course fibre and faster felting. It does leave larger holes so it is not a good finishing needle. The 38 gauge triangular needle is great as an all purpose felting needle and a must have in your collection. The 40 gauge triangular needle is used for fine detail and a finishing needle on faces and detailed felted pieces. The star shaped needles have one extra side on them and work great and a bit faster because of the one extra side. I prefer the star sided needles myself. The higher the gauge #, the finer the needle.