For anyone looking for cheap or free saw dust.
#1 The best dust would be from a Radial Saw, Chop Saw (miter saw), or Crosscuts from a Table saw. Most other dust is either too heavy or too light.
#2 I worked in Cabinet shops for many years, and had my own shop for 10 years. The only way you can get hardwood sawdust without any flake board, fiber core, or soft woods not good for smoking, like Pine, would be if your personal friend has a shop. Other shops are not going to bother to separate their sawdust for you. In most shops, all of the dust from all the machines gets sucked up into the same collection system, which mixes good smoking dust with dangerous to use dust.
#3 Chainsaw dust should not be used unless you drain your chain oil & replace it with cooking oil.
Bear