To add...
-Avoid flexible plastic duct. Use 26ga. (not lighter 28ga.) smooth sheet metal duct and elbows for as much of the system as possible, should be available from your local big box stores. Use 3 equally spaced sheet metal screws per joint to hold them together. Support the duct along its length with plumbing J-hooks or metal strapping.
-I avoid height changes in the duct runs. I have my ducts running along the walls at the similar height of the source of the dust. Why fight gravity if you don't have to?
-In the direction of air flow, the crimped end of the duct goes into the uncrimped end of the next downstream duct section. This lessens air leakage at joints, and less clogging of debris.
-Seal all duct joints, at connections and along the length, with UL181 labeled metal foil tape or paint-on duct mastic (messy). Even tape the joints of elbows. Sealing prevents air leakage and suction drops at the points of use.
-2 elbows forming a long-sweep bend may(?) be more efficient than a single elbow making a short-sweep bend. 90° elbows restrict air as much as 5' of straight pipe. Plan your layout carefully.
-Blast gates leak air. Cheap gates leak more air. Buy good blast gates. Good ones are expensive. Or, turn tapered wood plugs to jam into the ends of branch openings when a branch is not in use, think a cork in a bottle. They won't leak any more air than blast gates, and maybe less if you build them well. And they cost almost nothing.
-Keep branches as short as possible to maintain suction efficiency. Consider where the collector and machines are located relative to each other.
The thread of my dust hoods at each lathe. They have proven to be very effective at grabbing airborne dust before it can leave the area of the lathe. Just today, on my long bed lathe, I was sanding spindles 24" away (down the bed) from the duct inlet, and dust was still being pulled into my hood enclosure. More about them in this thread-
As I started in this thread (with 2 videos)
https://www.aawforum.org/community/...dest-shop-with-dust-collection-details.23325/ which wandered and meandered with a lot of good information, here is the final result of my version of the Richard Raffan-inspired dust hood I built for my Oneway 1224.
Raffan, nor Tomislav Tomasic in his video, had no plans to build it. It's easy to see that their setups are pretty casual in design, as is mine. Will my plastic bowl collect more effectively than Raffan's angle cut pipe? I don't know, but my bowl hood was my...
There are probably other things I'm not thinking of, but these points, building a good duct system, will go far to make any collector as efficient and effective as possible.