Connect a DeWalt DWS779 / DWS780 miter saw port to a 4 in dust-collector hose
How to join a DeWalt DWS779 / DWS780 miter saw port to a 4 in dust-collector hose, and what stops it leaking dust.
Not compatible without stepping down. A 4 in dust-collector hose is far larger than the DeWalt DWS779 / DWS780 miter saw port, so it needs a 1-5/8 in to 4 in step reducer.
Rings drawn to scale from the measured diameters in the table below.
The two ends
| End A | DeWalt DWS779 / DWS780 miter saw port (1-5/8 in OD, 41 mm OD) |
|---|---|
| End B | 4 in dust-collector hose (4-1/4 port in OD, 4 in ID) |
| Fit type | male port into hose cuff |
| Reducer needed | 1-5/8 in to 4 in step reducer |
Shop notes
The port is about 41 mm and the hose about 102 mm, a gap of 61 mm, so the hose simply swallows the port with no contact. A 1-5/8 in to 4 in step reducer is needed, and even reduced the airflow is mismatched between the DeWalt DWS779 / DWS780 miter saw port and the 4 in dust-collector hose.
Wrapping tape to close a 61 mm gap never seals cleanly and chokes the airflow further. Step the sizes properly, or pair each end with a fitting closer to its own size.
The reducer to buy
Search Amazon for 1-5/8 in to 4 in step reduceraffiliate searchRelated connections
- DeWalt DWS779 / DWS780 miter saw port1-5/8 in OD (approx 41 mm)
- 4 in dust-collector hose4 in ID
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- 4 in dust-collector hose to 2-1/2 in shop-vac hoseneeds a reducer