PortMatchMatch any tool dust port to any shop-vac or collector hose, with the exact reducer

Not compatible without stepping down. A 4 in dust-collector hose is far larger than the Mirka DEROS sander port, so it needs a 27 mm to 4 in step reducer. Measured OD and ID of each end, the real-world trap, and the exact reducer to buy.

Updated 05 September 2026.

CONNECTION

Connect a Mirka DEROS sander port to a 4 in dust-collector hose

How to join a Mirka DEROS sander port to a 4 in dust-collector hose, and what stops it leaking dust.

Not compatible

Not compatible without stepping down. A 4 in dust-collector hose is far larger than the Mirka DEROS sander port, so it needs a 27 mm to 4 in step reducer.

END B101.6 mm4 in dust-collector hose (4-1/4 port in OD, 4 in ID)
END A27 mmMirka DEROS sander port (1-1/16 in OD, 27 mm OD)

Rings drawn to scale from the measured diameters in the table below.

The two ends

End AMirka DEROS sander port (1-1/16 in OD, 27 mm OD)
End B4 in dust-collector hose (4-1/4 port in OD, 4 in ID)
Fit typemale port into hose cuff
Reducer needed27 mm to 4 in step reducer

Shop notes

The port is about 27 mm and the hose about 102 mm, a gap of 75 mm, so the hose simply swallows the port with no contact. A 27 mm to 4 in step reducer is needed, and even reduced the airflow is mismatched between the Mirka DEROS sander port and the 4 in dust-collector hose.

Wrapping tape to close a 75 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

Shop 27 mm to 4 in step reducer on AmazonaffiliateFind 27 mm to 4 in step reducer on eBayaffiliate

Related connections

Questions and answers

Connect a Mirka DEROS sander port to a 4 in dust-collector hose?

Not compatible without stepping down. A 4 in dust-collector hose is far larger than the Mirka DEROS sander port, so it needs a 27 mm to 4 in step reducer.