Table saws produce dust in two places: above the blade guard and below the table in the blade housing. A good dust collection setup captures both. Most shop vac setups only capture one, which is why many woodworkers feel like their dust collection is not working well.
Here is the complete setup for any table saw.
Two Dust Sources, Two Ports
The blade guard above the table has a dust port. Most modern table saws include one. This port captures chips that fly upward as the blade exits the top of the workpiece.
The blade housing below the table is the bigger problem. Most of the dust goes downward through the table insert and falls into the housing. The below-table port captures this. It is usually the larger port, often 2-1/2 inch (63.5mm).
If you only connect to one port, you miss half the dust. A complete setup connects to both.
Port Sizes by Saw Type
| Saw Type | Below-Table Port | Blade Guard Port | Notes |
|---|---|---|---|
| Jobsite table saw (10 in.) | 2-1/2 in. (63.5mm) | 1-7/8 in. (47.6mm) | DeWalt DWE7491, Milwaukee 2736 |
| Contractor table saw | 4 in. (100mm) | 2-1/2 in. (63.5mm) | Ridgid R4518, Bosch GTS1041A |
| Cabinet table saw | 4 in. (100mm) | 4 in. (100mm) | Jet, Powermatic, Grizzly |
| Cordless table saw | 2-1/2 in. (63.5mm) | 1-7/8 in. (47.6mm) | DeWalt DCS7485, Milwaukee M18 FUEL |
The Jobsite Table Saw Setup
For a jobsite table saw (the most common home shop saw), the below-table port is 2-1/2 inch. Here are your options:
Option 1: Connect a shop vac with a 2-1/2 inch hose directly to the below-table port. This works best for volume. Use a 6 to 9 gallon vac with at least 6 amps.
Option 2: Connect a standard 1-7/8 inch shop vac using a 63.5mm to 47.6mm reducer. You lose some flow capacity, but the higher velocity from the smaller hose diameter helps with chip transport.
For the blade guard port (1-7/8 inch on most jobsite saws), connect a standard 1-7/8 inch vac hose directly or use a splitter to run both ports to one vac.
Running Both Ports to One Vac
The simplest approach is a Y-fitting hose splitter. One inlet connects to the below-table port. One inlet connects to the blade guard port. The outlet goes to the vac.
Y-fittings cost $10 to $15 and split the suction between both ports. Each port gets roughly half the vac's suction. This is usually enough for both. The below-table port gets a larger share because it is the larger opening, which naturally restricts flow less.
If you have a larger vac (9 gallon, 6+ amp), running both ports with a Y-fitting works well. A small 4.5-amp vac may not have enough suction to split effectively.
The Cabinet Saw and Contractor Saw Setup
Cabinet saws and contractor saws need a dedicated dust collector, not a shop vac. The 4-inch port requires a dust collector with a 4-inch duct to move the volume of chips a cabinet saw generates.
A 1.5 HP single-stage dust collector ($200 to $400) connects to the 4-inch port with a 4-inch flex hose. This provides enough airflow for continuous operation on a 10-inch cabinet saw.
You can use a shop vac as a temporary solution, but you will fill it quickly and suction will drop as the canister fills. For regular cabinet saw use, a dust collector is the right tool.
Cordless Table Saws
The DeWalt DCS7485T2 (FLEXVOLT 60V) and Milwaukee M18 FUEL 2736-21HD both have 2-1/2 inch below-table ports. These work with the same shop vac setup as corded jobsite saws.
The DeWalt DCS7485 pairs well with the DCV586B cordless vac (1-7/8 inch hose) using a 63.5mm to 47.6mm reducer. This gives you a cordless saw plus cordless vac with no cords on the jobsite.
Tips for Better Capture
Keep the table insert tight to the blade slot. Gaps around the insert let chips escape downward without entering the below-table housing. Replace worn table inserts.
Make sure the blade guard is in place for every rip and crosscut. The guard channels chips toward its port and also protects you from the blade. Do not skip it just because it is in the way.
Empty the vac before long ripping sessions. A table saw ripping 3/4 inch plywood fills a 4.5-gallon vac in about 10 to 15 minutes. Start with an empty canister.