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

Not compatible without stepping down. A 1-7/8 in shop-vac hose is far larger than the Wood lathe dust hood 4 in port, so it needs a 4 in to 1-7/8 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 Wood lathe dust hood 4 in port to a 1-7/8 in shop-vac hose

How to join a Wood lathe dust hood 4 in port to a 1-7/8 in shop-vac hose, and what stops it leaking dust.

Not compatible

Not compatible without stepping down. A 1-7/8 in shop-vac hose is far larger than the Wood lathe dust hood 4 in port, so it needs a 4 in to 1-7/8 in step reducer.

END A99 mmWood lathe dust hood 4 in port (3-15/16 in OD, 99 mm OD, 91 mm ID)
END B47.6 mm1-7/8 in shop-vac hose (1-7/8 in ID)

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

The two ends

End AWood lathe dust hood 4 in port (3-15/16 in OD, 99 mm OD, 91 mm ID)
End B1-7/8 in shop-vac hose (1-7/8 in ID)
Fit typemale port into hose cuff
Reducer needed4 in to 1-7/8 in step reducer

Shop notes

The hose is about 48 mm and the port about 99 mm, a gap of 51 mm, so the port simply swallows the hose with no contact. A 4 in to 1-7/8 in step reducer is needed, and even reduced the airflow is mismatched between the Wood lathe dust hood 4 in port and the 1-7/8 in shop-vac 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.

The reducer to buy

Shop 4 in to 1-7/8 in step reducer on AmazonaffiliateFind 4 in to 1-7/8 in step reducer on eBayaffiliate

Related connections

Questions and answers

Connect a Wood lathe dust hood 4 in port to a 1-7/8 in shop-vac hose?

Not compatible without stepping down. A 1-7/8 in shop-vac hose is far larger than the Wood lathe dust hood 4 in port, so it needs a 4 in to 1-7/8 in step reducer.