Connect a 1-1/4 in shop-vac hose to a 1-7/8 in shop-vac hose
How to join a 1-1/4 in shop-vac hose to a 1-7/8 in shop-vac hose, and what stops it leaking dust.
Not a direct fit. Joining the 1-1/4 in shop-vac hose to a 1-7/8 in shop-vac hose needs a 1-1/4 in to 1-7/8 in step reducer.
Rings drawn to scale from the measured diameters in the table below.
The two ends
| End A | 1-1/4 in shop-vac hose (approx 1-1/2 cuff in OD, 1-1/4 in ID) |
|---|---|
| End B | 1-7/8 in shop-vac hose (1-7/8 in ID) |
| Fit type | cuff to cuff via a step reducer |
| Reducer needed | 1-1/4 in to 1-7/8 in step reducer |
Shop notes
Measured across the joint between the 1-1/4 in shop-vac hose and the 1-7/8 in shop-vac hose, the hose (48 mm) is 16 mm larger than the smaller hose (32 mm), so the hose rattles inside without gripping. A 1-1/4 in to 1-7/8 in step reducer closes that 16 mm step so the two hold together instead of leaking at the gap.
A 16 mm mismatch feels close enough to force, and it will hold for a minute before it works loose under airflow. Fit the step ring rather than trusting friction on a gap this size.
The reducer to buy
Search Amazon for 1-1/4 in to 1-7/8 in step reduceraffiliate searchRelated connections
- 1-1/4 in shop-vac hose1-1/4 in (approx 32 mm)
- 1-7/8 in shop-vac hose1-7/8 in (approx 48 mm)
- DeWalt DWS779 / DWS780 miter saw port to 1-1/4 in shop-vac hoseneeds a reducer
- DeWalt random-orbit sander stepped port to 1-1/4 in shop-vac hoseneeds a reducer
- 35 mm EU power-tool port (DeWalt / Bosch / Makita) to 1-1/4 in shop-vac hoseneeds a reducer
- 1-7/8 in shop-vac hose to 2-1/2 in shop-vac hoseneeds a reducer