A shop vac works well for portable tools. But if you have stationary tools like a table saw, jointer, bandsaw, or planer, a central dust collection system is the right choice. One unit handles all of them. One switch clears the air. Here is how to build it.
What You Need to Start
Three things define a central dust collection system:
- A dust collector unit (the motor and bag)
- A duct network connecting the tools
- Blast gates to control airflow to each tool
Each machine connects to the main duct via a branch drop. You open the blast gate for the tool you are using and close the rest. This sends all available suction to the one active tool.
Choosing the Collector Size
Dust collectors are rated in CFM and horsepower. The right size depends on the largest tool in your shop and the length of your duct run.
| Shop Size | Largest Tool | Recommended Collector |
|---|---|---|
| Small (1-2 tools) | Table saw or planer | 1 HP / 650 CFM |
| Medium (3-5 tools) | Table saw + jointer | 1.5 HP / 900 CFM |
| Large (5+ tools) | Multiple stationary tools | 2 HP / 1200+ CFM |
Longer duct runs lose CFM to friction. Add about 10 percent to your CFM estimate for each 10 feet of main duct beyond 15 feet total run length.
4-Inch vs. 6-Inch Main Duct
Most home shop central systems run a 4-inch main duct. 4-inch PVC duct is affordable, easy to work with, and fits most shop configurations.
6-inch duct moves more air with less pressure loss. It is the better choice for shops with long duct runs, multiple large tools, or a 2 HP plus collector. But 6-inch fittings cost more and are harder to find.
The most common home shop setup: 4-inch main duct with a 1.5 HP collector.
Planning the Duct Layout
Sketch your shop layout before buying any duct. Mark where each stationary tool sits. Run the main duct overhead or along one wall. Plan a branch drop down to each tool.
Rules that keep duct performance high:
- Keep total main duct length under 25 feet when possible
- Use smooth-sweep elbows, not sharp 90-degree fittings
- Use wye fittings for branches, not tee fittings
- Connect the collector at one end, not the middle
- Put larger tools closer to the collector
Blast Gates
Blast gates are inline valves that open and close airflow to each branch. They are the most important part of a multi-tool central system. Without blast gates, suction divides between all open branches, which means no single tool gets enough airflow.
Manual plastic blast gates cost about $8 each. Automated blast gates cost $20 to $40 but open and close automatically when a tool turns on. For a shop with 4 or more tools, automated gates are worth the cost.
Connecting Portable Tools
A central dust collector is mainly for stationary tools. For portable tools like circular saws, sanders, and routers, you usually still connect a shop vac or dust extractor directly to the tool port.
You can run a flexible hose drop from the central duct to a wall port near your workbench. Portable tools can then connect to the wall port via hose. This works well for hand tools if the collector has enough CFM to handle the additional branch.
Ports on Stationary Tools
Stationary tools have larger ports than portable tools. Common sizes:
| Machine | Port Size |
|---|---|
| Table saw (cabinet) | 4 inch (100mm) |
| Table saw (contractor) | 2-1/2 inch (63mm) |
| Jointer (6-8 inch) | 4 inch |
| Bandsaw | 4 inch |
| Planer | 4 inch |
| Belt/disc sander | 4 inch |
| Drill press | None or 2-1/2 inch |
| Lathe | None; floor sweep |
Connect 4-inch tool ports to 4-inch duct branches directly with a 4-inch wye fitting and blast gate. Connect 2-1/2-inch ports to a 4-to-2.5-inch reducer at the branch drop, then a short flexible hose to the tool.
PVC vs. Metal Duct
PVC duct is the most popular choice for home shops. It is cheap, easy to cut, and light. The main concern is static electricity. Fine sawdust in a PVC duct can build up a static charge. Ground the duct with bare copper wire wrapped around the outside and connected to a ground source to prevent static discharge.
Spiral steel duct is better for large shops and is naturally grounded. It costs more and is harder to modify.
Adding a Cyclone
A cyclone separator sits between the duct network and the dust collector. It drops most of the debris into a barrel before the air reaches the collector bag. This keeps the bag cleaner, extends bag life, and keeps the motor running at full power.
For a shop with a table saw, planer, or jointer, a cyclone is worth the investment. A 1 to 2 HP cyclone unit costs $200 to $400 and dramatically reduces how often you empty the collector bags.
The Simplest Starting Point
If you have two tools (a table saw and a jointer), start with:
- A 1.5 HP single-stage dust collector
- 15 feet of 4-inch PVC duct
- Two blast gates
- A couple of 4-inch wye fittings and elbows
Total cost: $300 to $500. The difference in air quality and cleanup time is immediate and significant.
For portable tools at a central wall port, use our configurator to find the right flexible hose adapter from your tool port to the wall fitting size.