Ball point needles should be used for all knit fabrics. The ball point prevents fraying of the yarn in the fabric. It pushes the yarn apart rather then piercing through it.
Embroidering hats and woven fabrics, you should use regular or sharp point needles
DB-K5 needles are made with an oversized eye allowing the thread to flow through easier without fraying or snapping
16×257 needles has a smaller eye which is recommended for higher stitch counts and fine lettering
75/11 is the most popular all-purpose size, for tougher fabrics use a 80/12 and for spandex or Lycra 70/10
15×1 is the proper needle for home embroidery machines
Titanium needles are significantly stronger. This reduces needle breakage, bending and distortion.
