Connect a Bosch GCM12SD miter saw port to a 1-7/8 in shop-vac hose
How to join a Bosch GCM12SD miter saw port to a 1-7/8 in shop-vac hose, and what stops it leaking dust.
Not a direct fit. Joining the Bosch GCM12SD miter saw port 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 | Bosch GCM12SD miter saw port (1-1/4 in ID) |
|---|---|
| End B | 1-7/8 in shop-vac hose (1-7/8 in ID) |
| Fit type | hose cuff into female socket |
| Reducer needed | 1-1/4 in to 1-7/8 in step reducer |
Shop notes
Measured across the joint between the Bosch GCM12SD miter saw port and the 1-7/8 in shop-vac hose, the hose tip (48 mm) is 16 mm larger than the port socket (32 mm), so it will not seat. 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
- Bosch GCM12SD miter saw portrear approx 1-1/4 in ID (32 mm)
- 1-7/8 in shop-vac hose1-7/8 in (approx 48 mm)
- 1-7/8 in shop-vac hose to 2-1/2 in shop-vac hoseneeds a reducer
- DeWalt DWS779 / DWS780 miter saw port to 1-7/8 in shop-vac hoseneeds a reducer
- DeWalt miter saw dust elbow (1-1/2 in outer) to 1-7/8 in shop-vac hoseneeds a reducer
- DeWalt random-orbit sander stepped port to 1-7/8 in shop-vac hoseneeds a reducer