Buying task · Blast gates
Blast gates
Choose a blast gate by the standard each end takes (hose, fitting or pipe), its nominal and actual end size, the clamps it needs and its maker's body and slide.
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Short answer
Choose a blast gate by its ends, not its body. Most 4 in gates have male ends that go inside 4 in hose under a clamp, so they need a cuff or adapter to meet a machine port or a PVC pipe. Read the maker's actual end size, buy the clamps it needs, and treat metal or plastic as the maker's description.
What this topic covers
A blast gate is a sliding gate in a dust line. Close it and that branch stops drawing. Open it and the machine on that branch gets the airflow. Everything on this site is a manual gate: we cover no automatic gates, switches or wiring.
The hard part is the two ends. A gate sits between two other parts, and each end has to match the hose, fitting or pipe beside it.
The decisions, in order
1. The standard each end takes. A gate can be made for hose, for dust-collection fittings or for a pipe system. A gate with hose-style ends joins 4 in hose directly. It does not join sewer-and-drain PVC without an adapter: Rockler says S&D pipe does not connect directly to most dust fittings without one.[1] The fitting standards guide explains the families.
2. Nominal and actual end size. POWERTEC lists its 70135 gate outlet as nominal 4-inch OD, with an actual size that tapers from 3-29/32 to 3-31/32 inches.[2] That taper is made to go inside 4 in hose. It is not a socket for a 4 in OD machine port. The same maker page carries a broader fit line that conflicts with that single size; we go by the stated dimensions.
3. Clamps. Infinity Tools says its 4-inch gate has tapered fittings on both sides to accept 4-inch hose and that hose clamps are required.[3] Plan one clamp per hose end. The hose clamps guide sizes them by the hose's outside diameter.
4. Body and slide. POWERTEC describes the 70135 as a cast aluminum body with a steel sliding gate.[2] It says the gate has an open slot in the back for self-cleaning and a locking stop for gate alignment.[2] That self-cleaning slot is POWERTEC's design description. Claims that a gate will never clog or never leak are marketing; no maker we read publishes a measurement.
5. Unused openings. Harbor Freight's manual for the Central Machinery 59726 says to cap the unused inlet with the supplied inlet cap when only one inlet is in use.[4] A gate does the same job on a branch you close.
How to choose
| Where the gate goes | End type to look for |
|---|---|
| Between two lengths of 4 in hose | Male ends on both sides, made to go inside 4 in ID hose, plus two clamps |
| Hose to a machine with a 4 in OD port | A male gate plus a flexible cuff, or a gate with a flexible machine end |
| Hose to a smaller 2-1/2 in OD tool port | A gate with a 2-1/2 in flexible end on the tool side |
| In a PVC pipe run | The pipe's own gates or a gate with adapters made for that pipe |
Picks that fit5 products
For 4 in ID hose on both sides, choose POWERTEC's 70135 aluminum gate (the 2-pack, 70135-P2), POWERTEC's 70108 plastic gate (single), Rockler's 4 in metal gate (single, wall bracket sold separately) or Rockler's 4 in to 4 in Ready-Mount gate if you want a wall bracket built in.
More on choosing
For a machine with a 2-1/2 in OD port on a 4 in hose, choose Rockler's 4 in to 2-1/2 in tool blast gate. Each needs a clamp per hose end; POWERTEC says the 70108 needs a flex cuff to meet a 4 in OD port. On Amazon, check that 'Ships from / Sold by' shows Amazon.com or the brand.
Aluminum gate with dimensioned 4 in ends
4 in hose to a 2-1/2 in OD tool port
Rockler 4 in metal blast gate
The 4 in blast gates shortlist sets out each gate's stated ends and limits.
Every page on blast gates
Guides
- Blast gate sizes, ends and materials
- A small-shop duct run parts list
- Dust hose clamps by outside diameter
- Dust collection fitting standards: hose, PVC and metal
Shortlist and standard page
Key terms
blast gate, sliding gate, self-cleaning slot, male end, hose clamp, drop and inlet cap.
Everything in this topic
Guides
- Blast gates: sizes, end types, metal vs plasticHelps you choose a blast gate whose ends fit your hose or fittings, without relying on unmeasured material claims.
Shortlists
- 4 in blast gates with stated end sizesHelps you pick a manual 4 in blast gate whose two ends fit the hose or port on each side, and plan the clamps it needs.
Common questions
What size blast gate do I need?
One whose ends fit what they join. POWERTEC's 70135 outlet is nominal 4-inch OD, tapering from 3-29/32 to 3-31/32 inches, sized to go inside a 4-inch hose. More in Blast gates: sizes, end types, metal vs plastic
Do blast gates fit inside or over the hose?
Check each maker's description. POWERTEC's 70135 outlet is a nominal 4-inch OD end sized to go inside hose, and Infinity says its 4-inch gate has tapered fittings on both sides to accept 4-inch hose. More in Blast gates: sizes, end types, metal vs plastic
Are metal blast gates better than plastic?
No source in our register measures leakage or clogging for either, so we cannot say. Compare the ends and the features each maker states. More in Blast gates: sizes, end types, metal vs plastic
Do I need clamps on a blast gate?
Where the gate maker says so. Infinity says hose clamps are required on its 4-inch blast gate. More in Blast gates: sizes, end types, metal vs plastic
Do these gates fit straight onto a 4 in machine port?
No. Their 4 in ends are male and sized to go inside 4 in ID hose. POWERTEC lists the 70135's end as tapering from 3-29/32 to 3-31/32 inches, so a 4 in OD port needs a cuff or a short hose between them. More in 4 in blast gates with stated end sizes
How many clamps do I need?
One per hose end. Infinity Tools says hose clamps are required on its 4-inch gate, and the same applies to any gate with tapered hose ends. More in 4 in blast gates with stated end sizes
Are there automatic gates here?
No. We cover manual gates only, with no switches, remotes or wiring. More in 4 in blast gates with stated end sizes
Questions
What size blast gate do I need?
The size of the hose or fitting on each side, read as an actual end size. POWERTEC lists its 70135 as nominal 4-inch OD with an end that tapers from 3-29/32 to 3-31/32 inches, which is made to go inside 4-inch hose.[2]
Metal or plastic?
Choose by the ends first; the body is a maker description. POWERTEC describes the 70135 as a cast aluminum body with a steel sliding gate. We found no source that compares metal and plastic gates in use.[2]
Do blast gates leak?
We found no measurement in our sources. Makers' wording such as 'designed for eliminating air leakage' is not a measured figure, so we do not repeat it as fact.
Do I need a gate on every machine?
A gate lets you close branches you are not using. On a collector with more than one inlet opening, Harbor Freight's 59726 manual says to cap the unused inlet with the supplied cap when only one inlet is in use. Follow your own collector's manual.[4]