PortMatch
CONNECTION

Connect a 35 mm EU power-tool port (DeWalt / Bosch / Makita) to a 4 in dust-collector hose

How to join a 35 mm EU power-tool port (DeWalt / Bosch / Makita) 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 35 mm EU power-tool port (DeWalt / Bosch / Makita), so it needs a 35 mm to 4 in step reducer.

END B101.6 mm4 in dust-collector hose (4-1/4 port in OD, 4 in ID)
END A35 mm35 mm EU power-tool port (DeWalt / Bosch / Makita) (1-3/8 in OD, 35 mm OD)

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

The two ends

End A35 mm EU power-tool port (DeWalt / Bosch / Makita) (1-3/8 in OD, 35 mm OD)
End B4 in dust-collector hose (4-1/4 port in OD, 4 in ID)
Fit typemale port into hose cuff
Reducer needed35 mm to 4 in step reducer

Shop notes

The port is about 35 mm and the hose about 102 mm, a gap of 67 mm, so the hose simply swallows the port with no contact. A 35 mm to 4 in step reducer is needed, and even reduced the airflow is mismatched between the 35 mm EU power-tool port (DeWalt / Bosch / Makita) and the 4 in dust-collector hose.

Wrapping tape to close a 67 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.