Dimensions Confirmed by DEWALT
DEWALT support states that its standardized miter-saw duct measures 1.5 in. on the outside and 1.375 in. on the inside. The same note says a 1.5 in. hose fits over the duct and a 1.25 in. hose can fit inside it.
| Hose / cuff | Documented fit | Action |
|---|---|---|
| 1-1/4" | Inside the duct | Check the cuff’s actual outside diameter |
| 1-1/2" | Over the outside of the duct | Check the cuff’s actual inside diameter |
| 1-7/8" / 2-1/2" | Adapter or reducer required | Measure both sides before purchase |
Choose the Connection for Your Hose
If your cuff is genuinely sized as a 1-1/4 in. male insert, start with the inside fit. For a 1-1/2 in. female cuff, start with the outside fit. Do not force a nominal 1-7/8 or 2-1/2 in. hose; use a reducer whose inside and outside diameters match both parts.
A hose’s nominal size does not always describe its cuff dimension. MatchMyTools therefore treats 1-1/4 and 1-1/2 in. as the two documented arrangements while still requiring a real geometry check.
Verify the Fit Before Buying
- Disconnect the saw and remove the dust bag.
- Measure the duct OD and ID without deforming it.
- Measure the mating side of the hose cuff.
- Check taper, available insertion depth and sealing.
Frequently Asked Questions
What is the DWS779/DWS780 duct size?
DEWALT’s standardized miter-saw duct note specifies 1.5 in. outside and 1.375 in. inside.
Can a 1-1/4 in. hose fit directly?
Yes, when its actual cuff is designed to insert into the duct; DEWALT documents this inside fit.
What should I use with a 2-1/2 in. hose?
Use an adapter or reducer selected from the real duct and cuff dimensions, not nominal sizes alone.
Technical Source
The dimensions in this guide come from DEWALT’s official note on miter-saw dust-duct diameter. DEWALT miter-saw dust duct.
Disconnect the machine before measuring. Never force a fitting, and keep guards, duct, and dust bag or hose installed according to the saw manual.