DeWalt DCS391B 20V MAX Circular Saw Dust Port Size and Vacuum Adapter Guide
DeWalt 20V MAX 6-1/2" Circular Saw
Specifications
DeWalt DCS391B 20V MAX Circular Saw Dust Port Size and Vacuum Adapter Guide
The DeWalt DCS391B is the 20V MAX 6-1/2 inch circular saw. It runs on the 20V MAX battery and cuts boards fast. Like most cordless saws, it throws a lot of sawdust when you cut.
The saw uses a proprietary AirLock-style port on the rear, not a clean round port. A matching adapter collar is about 35 mm across. That figure comes from an AirLock collar, so treat it as close, not exact, and the tool-side spigot is its own proprietary shape. So measure your own port with calipers before you buy. A GulpDust PETG adapter is sized to the saw port on one end and your shop vac hose on the other end. No tape. No clamps.
DeWalt DCS391B Dust Port and Specs
Port size: please measure to confirm
Source verified, but only one side of the port was confirmed. Measure your port before you buy.
Source we cite: www.etsy.com
| Dust port outer diameter | 35.0mm (measure to confirm) |
| Port shape | Proprietary |
| Port location | Rear |
| Connection type | Friction fit |
| Blade size | 6-1/2 in. |
| Max speed | 5,150 RPM |
| Weight | 6.5 lbs |
DeWalt DCS391B Dust Port Size: Proprietary AirLock Port, Collar About 35 mm
The dust port on the DCS391B is a proprietary AirLock-style port, not a clean round port. A matching adapter collar is about 35 mm across. That figure comes from an AirLock collar, so it is close, not a hard spec. The tool-side spigot is its own special shape.
Most shop vac hoses are 1-7/8 inch or 2-1/2 inch. They do not fit this AirLock port on their own. That gap is why dust blows past the hose and into the air.
A GulpDust adapter is printed to match the saw port on one end and your vac hose on the other end. Measure your port first so you order the size that seals tight.
How to Measure Your DeWalt DCS391B Dust Port
Look at the rear port on the saw. It is an AirLock-style spigot, so write down the width at the tip and the width at the base. Wipe out any sawdust so your reading is clean.
Close caliper jaws around the OUTSIDE of the port. Then take the inner reading the same way. Those numbers tell us the shape so the adapter can be matched to it.
How to Connect a Shop Vac to the DeWalt 20V MAX 6-1/2 Inch Circular Saw
First, look at the rear port on the saw. Wipe out any sawdust so the adapter seats clean.
Press the small end of the PETG adapter onto the port. It is a friction fit, so it holds with a firm push. Then press your shop vac hose onto the other end.
Turn the vac on before you cut. Let it run for a second after each cut so the hose clears. This setup catches most of the dust at the blade instead of on your bench.
Best Vacuum and Dust Extractor Setup for the DeWalt DCS391B
Any shop vac works. A vac with an auto-start outlet is even better, because it turns on when the saw turns on. You do not have to remember to flip a switch.
If you cut a lot, add a cyclone separator between the saw and the vac. The separator drops the heavy chips into a bucket so your vac filter stays clean longer.
Keep the hose short and straight when you can. Long, kinked hoses cut your suction and let dust settle inside.
DeWalt DCS391B Dust Collection FAQ
What size is the dust port on the DeWalt DCS391B?+
The saw uses a proprietary AirLock-style port. A matching collar is about 35 mm, verified from an AirLock adapter. The tool-side spigot is its own shape with no confirmed size, so measure your own port before you buy.
Does the DeWalt DCS391B work with a regular shop vac?+
Yes, with the right adapter. A standard shop vac hose does not fit this AirLock port. The GulpDust PETG adapter fits the saw port on one end and your vac hose on the other. Measure your port first so the fit is tight.
Do I need clamps or tape to attach the adapter?+
No. The adapter is a friction fit. You push it into the port and it holds. The same goes for the vac hose end.
Will dust collection slow down the saw?+
No. The adapter only routes the dust the saw already makes. It does not touch the blade or the motor. The saw still spins at 5,150 RPM.
Can I print this adapter myself?+
Yes. You can buy the printed PETG part shipped from the US, or download the STL file and print it at home. We suggest PETG with 3 walls and 25 percent infill.
Does the same adapter fit other DeWalt 20V MAX tools?+
Not always. DeWalt 20V MAX tools use different ports. This saw uses a proprietary AirLock-style port, while other tools use their own shapes. Check each tool page for its verified port size before you buy.
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