Did you ever wonder about the different types of V-nails?
HDF/MDF, SPT and HPT
You might have to use a microscope to see the difference, but….
SPT or Softwood nails are sharpened on the inside edge only, also they have a sharper angle grind to “cut” thru rather than push.
Softwoods such as poplar, pine and cedar generally have a more open grain and require a sharper v-nail to join the molding.
You would also use softwood v-nails for plastic/polystyrene frame molding.
HPT or Hardwood v-nails are sharpened on both edges to counter the resistance of such woods.
Hardwood nails have a blunter grind as well.
Hardwoods such as oak, ash, hickory, cherry, maple, and walnut have a tighter grain and require a blunt v-nail to join the molding.
MDF nails are slightly thicker than the hard or soft to “push” into and push aside the Fiberboard particles
AMP Color Identification Chart for V-Nail Types