Quote Originally Posted by Chris Parks View Post
Don't mind me, carry on and waste the capacity of 6" ducting, I can only advise what I know as good fact and no more. You have just told us that the system as you installed it is only going to flow as much as a 4" system and at a slower air speed which will result from the reduced air flow.
I had no practical way to avoid the use of flex hose - all machines are mobile - and am pretty sure that 6" flex hose will carry more air than 4" flex hose. What I did find to help is to partially open a blast gate upstream from the flex hose. Some machines, the Jet JJP-12 for one, have no practical way to upsize the dust collection plumbing.