Fitting standard
4 in dust-collection hose fittings: what joins them and what does not
Hose fittings are a catalog family sized to slip into or over flex hose and machine ports, not a published standard. Makers' dimensions, joins and limits.
Also listed as 4 in hose fittings, dust collection fittings, flex hose fittings
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Short answer
Dust-collection hose fittings are a catalog family sized to slip into or over flexible hose and machine ports, not a published standard, and each maker's dimensions differ: POWERTEC lists its 70136 4 in end at 3-61/64 in OD and its 70135 gate taper at 3-29/32 to 3-31/32 in. They meet PVC pipe only through an adapter. The catch: some fittings are hose-only, like POWERTEC's 70136. See duct fitting standards.
What fitsAll 5 items that fit
- WyePOWERTEC 70106 4 in Y-fitting dust hose connectorCheck price on Amazon
- ReducerPOWERTEC 70136 4 in to 2‑1/2 in cone reducerCheck price on Amazon
- Metal blast gatePOWERTEC 70135 4 in aluminum blast gateCheck price on Amazon
Key facts
- What the standard or system covers
- A catalog family of fittings sized to slip into or over flexible hose and machine ports; no published standard sets their dimensions, and each maker's differ[1][2][3]
- Marking to look for
- Not confirmed
- Published dimensions
- POWERTEC 70136 4 in end: 3-61/64 in OD, 3-41/64 in ID; 2-1/2 in end: 2-15/32 in OD, 2-9/32 in ID. POWERTEC 70291 4 in end: 3.51 to 3.73 in taper. POWERTEC 70135 gate outlet: 3-29/32 to 3-31/32 in taper[1][2][3]Maker figures for these parts only, not a shared size.
- Joins directly to
- Flexible hose and, for some parts, machine ports: POWERTEC's 70136 fits 4 in and 2-1/2 in hoses; its 70291 friction-fits inside a 4 in nominal OD machine port; its 70291 small end fits inside most 2-1/2 in ID hoses[1][2]
- Joins only through an adapter
- [S&D PVC](/fitting-standards/sewer-and-drain-pvc): Rockler says it does not connect directly to most dust fittings without an adapter. [Schedule 40 PVC](/fitting-standards/schedule-40-pvc): through Rockler's 52680[4][5]
- Transition parts with stated ends
- Rockler 52680: 4.5 in ID rubber end and 3.99 in OD plastic end (to Schedule 40). WoodRiver 4 in S&D adapter: fits inside 4 in S&D with a 4.065 in ID, left-hand threaded hose only[5][6]
- Gates and fittings made to it
- POWERTEC 70135: cast aluminum gate with a steel slide. Infinity 115-313: 4 in gate with tapered fittings for 4 in hose, hose clamps required. Oneida Super Dust Deputy 4/5: tapered ports for friction-fit flex hose[3][7][8]
- Application limits
- POWERTEC says the 70136 fits hoses only and is not intended to fit a 2-1/2 in OD or 4 in OD equipment port directly[1]
- Not confirmed
- Not confirmed
Watch out for
- Two fittings with the same 4 in label can do opposite jobs: POWERTEC's 70136 fits hoses only, while its 70291 goes inside a machine port.
- Infinity says its 4 in gate needs hose clamps; a tapered fitting is not a locking joint on its own.
- POWERTEC's 70135 page also carries a broad size line that conflicts with its single 4 in size; go by the dimensioned taper.
What fits
Product details below are the seller's own description unless a source is shown. Pick the variant named for each item.
Wye
POWERTEC 70106 4 in Y-fitting dust hose connectorChoose the single 70106 4 in Y-fitting.
POWERTEC lists three 4 in ports of 3-61/64 in OD and 3-3/4 in ID, sized to go inside 4 in ID hose and held with band clamps.
Reducer
POWERTEC 70136 4 in to 2‑1/2 in cone reducerChoose the single 70136 cone reducer.
Hose to hose only, 4 in to 2-1/2 in; POWERTEC says it is not made to fit machine ports.
Metal blast gate
POWERTEC 70135 4 in aluminum blast gateChoose the 2-pack of 70135 gates.
POWERTEC lists a nominal 4 in OD outlet tapering from 3-29/32 to 3-31/32 in.
Plastic blast gate
POWERTEC 70108 4 in plastic blast gateChoose the 4 in 70108 gate.
POWERTEC lists 3-61/64 in OD, 3-3/4 in ID ends that accept 4 in ID hose and says a flex cuff is needed to meet a 4 in OD port.
Wall-mount gate
Rockler Dust Right 4 in to 4 in Ready-Mount self-cleaning blast gateChoose the 4 in to 4 in Ready-Mount gate.
Rockler lists nominal 4 in OD ends that take 4 in ID hose and an integral wall bracket.
Questions
Is there a standard size for 4 in dust fittings?
No source in our register publishes one. POWERTEC alone lists different 4 in dimensions for its 70136, 70291 and 70135.[1][2][3]
Can a 4 in hose fitting go straight into PVC pipe?
Rockler says S&D pipe does not connect directly to most dust fittings without an adapter, and it sells the 52680 to meet Schedule 40. See S&D vs Schedule 40.[4][5]
Does the POWERTEC 70136 fit my collector's port?
POWERTEC says no: the 70136 fits 4 in and 2-1/2 in hoses only and is not intended to fit equipment ports directly. See 4 in to 2-1/2 in reducers.[1]