What's inside
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In a compact workshop, the choice between one main dust-collection trunk with branches and separate runs from a collector comes down to layout, airflow, and how often you use more than one tool at a time. A trunk usually uses less duct and is easier to expand. Separate runs can be simpler when there are only two or three tools, but each still needs enough airflow and a practical way to connect to the collector.
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Start with the collector and the tools
Before buying duct, check the collector’s rated airflow, inlet size, and filter arrangement, then identify the tools that need extraction. A small benchtop sander and a planer do not have the same demands. A typical 4-inch connection may serve many small machines, while a table saw cabinet or planer can need more air than a compact collector can supply. The machine manual is a better starting point than assuming a larger duct will fix poor collection.
Also distinguish airflow from suction. A collector may show a strong sealed-inlet pressure rating but deliver much less airflow once connected to a long hose, elbows, a filter, and a tool port. Small ducts, sharp bends, leaks, and clogged filters all add resistance. If collection is weak at the machine, adding more branches can make matters worse.
How the layouts compare
| Factor | Main trunk with branches | Separate runs |
|---|---|---|
| Best fit | Several tools arranged along one wall or work area | Two or three tools near the collector |
| Duct use | Often less total pipe, with a shared main line | More independent pipe or hose from collector to each tool |
| Airflow control | Requires closing unused branches or balancing gates | Easy to dedicate a run, but simultaneous use still divides capacity |
| Expansion | Usually straightforward if the trunk is sized for future loads | Can mean rerouting or adding another collector connection |
| Common drawback | Leaky gates or poorly placed tees reduce performance | Long, narrow runs can be bulky and restrictive |
When a trunk line makes sense
Choose a trunk when tools form a row or a perimeter route and you want a permanent, tidy installation. Run the main line along the wall or overhead, with short branches to each machine. Use wyes rather than square tees where branches join; the smoother turn generally creates less turbulence and restriction. Keep flexible hose short—often 2 to 4 feet is enough for a machine that needs to move for maintenance.
Plan the trunk around the collector’s real capacity, not the number of ports you can install. If the collector has a 6-inch inlet but most tools have 4-inch ports, reducing near each branch may be practical; do not neck the whole main line down to 4 inches without checking the collector and tool requirements. A trunk does not magically provide full airflow to every open branch. In a small shop, operate one machine at a time and close unused gates.
For a wall-mounted system, smooth metal duct is durable and has less internal drag than a long stretch of corrugated hose. A metal dust-collection duct kit can suit a fixed layout, but verify diameters and fittings before ordering. Mixed nominal sizes do not always connect directly.
When separate runs are the better buy
Separate runs are reasonable when the shop has only a table saw and a planer, both close to the collector, or when tools move around and a permanent overhead route would be in the way. One run can terminate at each machine, with a blast gate at the tool end. This avoids a long trunk with several unused branches and may cost less if the runs are short.
It is not a good shortcut to connect multiple long 4-inch hoses to a collector and leave them all open. The collector pulls from every open path, so airflow at the active tool falls. Close the other runs, or use a gate you can reach without walking around a running machine. If both machines truly need to run together, size the collector and duct for that combined demand; many compact collectors are intended for one machine at a time.
Portable tools may be better served by a short hose and a quick connection than by permanent duct. A 4-inch dust-collection blast gate is useful only if it seals reasonably well and stays accessible. Cheap gates that jam with chips or leak around the slide can undermine the layout. Inspect and clean them periodically.
Sizing, installation, and safety details
Keep duct runs as short and direct as the shop allows. Avoid needless elbows, abrupt reducers, crushed flex hose, and sharp right-angle turns. A gentle bend is preferable where space allows. Seal joints with suitable tape or fittings so the system does not draw dusty air from the room instead of from the tool. Support overhead duct securely; a loaded or poorly supported line can sag, pull apart, or interfere with lighting and material handling.
Wood dust is a respiratory and fire hazard, not just a housekeeping problem. Use a collector with filtration appropriate for fine dust, and do not treat a basic chip collector as a substitute for a dust-rated air cleaner or a properly fitted respirator. Keep the collector and duct clear of ignition sources, empty bins before they become overloaded, and follow the collector maker’s grounding and bonding instructions. Plastic duct can build static; adding an improvised wire does not make an unsuitable system safe.
Before committing to a fixed trunk, mock up the route with the machines in their actual positions. Check that gates can be reached, stock can pass through, and the duct will not block lights, doors, or a future bench. If the layout is still changing, start with short runs and a portable connection. If the machines have settled into fixed positions, a trunk with well-placed branches is usually neater and easier to maintain. In either layout, a leak check and a test at the tool port are worth doing before you call the installation finished.