CONNECTION
Connect a 4 in dust-collector hose to a 2-1/2 in shop-vac hose
How to join a 4 in dust-collector hose to a 2-1/2 in shop-vac hose, and what stops it leaking dust.
Reducer required
Not a direct fit. Joining the 4 in dust-collector hose to a 2-1/2 in shop-vac hose needs a 4 in to 2-1/2 in dust-collector reducer.
END A101.6 mm4 in dust-collector hose (4-1/4 port in OD, 4 in ID)
END B63.5 mm2-1/2 in shop-vac hose (2-1/4 in OD, 2-1/4 in ID)
Rings drawn to scale from the measured diameters in the table below.
The two ends
| End A | 4 in dust-collector hose (4-1/4 port in OD, 4 in ID) |
|---|---|
| End B | 2-1/2 in shop-vac hose (2-1/4 in OD, 2-1/4 in ID) |
| Fit type | cuff to cuff via a step reducer |
| Reducer needed | 4 in to 2-1/2 in dust-collector reducer |
Shop notes
A 4 in collector hose (4 in ID) dwarfs a 2-1/2 in shop-vac hose, so they never seal directly. A moulded 4-to-2-1/2 in reducer, or a stacking set that steps 4 in hose down through 3 in and 2-1/2 in OD, lets a benchtop tool share a collector drop.
Stepping a 4 in collector down to 2-1/2 in throttles it to shop-vac airflow. If you routinely reduce a collector to 2-1/2 in, a dedicated shop vac on that tool moves more dust than the choked collector.
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