A very common, but difficult machine to evacuate saw dust from is the Chop Saw (Mitre Saw). Most Chop Saw manufacturers provide a 1″ diameter outlet collar on the blade guard. The collar will sometimes have a bag attachment that only a small amount of dust is thrown into. Otherwise, a shop vacuum or high velocity dust collector is required to pull dust from such a small opening. When woodworkers try to adapt this 1″ diameter pick up to their conventional dust collector they do not get any draw because of too much resistance.
For a regular saw dust collector it is like trying to drink a milkshake through a cocktail straw. We have found that creating a funnel effect under the base of the saw helps tremendously. When cutting, most of the sawdust goes through a slot in the base. First you have to cut a hole in the bench top just inside the legs (typically 10″ diameter). Take a 10SR05 Spun Reducer and push through the hole to underside of base, then fasten. You may have to notch the front of reducer collar for the mitre handle.
It is also a good idea to slice a piece of air hose and bond it to top edge of collar. This will act as a safety edge. Then connect the bottom collar of Spun Reducer (5″ diameter) to your dust collector system (550 CFM is required). Now we have created a nice flow of air around the saw base. You should also leave your dust bag attached to the 1″ collar. Your Chop Saw cutting will now be virtually dust free.