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CONNECTION

Connect a Bosch GTS1031 table saw port to a 4 in dust-collector hose

How to join a Bosch GTS1031 table saw 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 Bosch GTS1031 table saw port, so it needs a 2 in to 4 in step reducer.

END B101.6 mm4 in dust-collector hose (4-1/4 port in OD, 4 in ID)
END A51 mmBosch GTS1031 table saw port (2 in OD, 51 mm OD)

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

The two ends

End ABosch GTS1031 table saw port (2 in OD, 51 mm OD)
End B4 in dust-collector hose (4-1/4 port in OD, 4 in ID)
Fit typemale port into hose cuff
Reducer needed2 in to 4 in step reducer

Shop notes

The port is about 51 mm and the hose about 102 mm, a gap of 51 mm, so the hose simply swallows the port with no contact. A 2 in to 4 in step reducer is needed, and even reduced the airflow is mismatched between the Bosch GTS1031 table saw port and the 4 in dust-collector hose.

Wrapping tape to close a 51 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.