Buying task · Measuring and buying
Measuring and buying
Measure both diameters of every port and hose end, read each end's size on the listing, check who sells and ships it, read the return terms and search for recalls.
We may earn a commission if you buy through links on this page. How we make money
Short answer
Measure the inside and outside diameter of every port and hose end you need to join, and note which is male and which is female. Then buy only a part whose listing states each end's size, check who sells and ships it, read the return terms on the order page, and search the CPSC for recalls.
What this topic covers
Most dust-fitting mistakes happen before the box arrives. A part labeled 4 in or 2-1/2 in may be sized to go inside a hose, over a port or into a pipe. A listing may give one number for a part with two ends. And the seller may not be the brand. This hub covers the steps between "I need an adapter" and "I placed the order."
The decisions, in order
1. Measure both diameters. Rockler advises measuring both the inside and outside diameter of each tool port and hose connector, because the port's outside diameter has to match the hose's inside diameter.[1] Write down every end you will join: size, ID or OD, male or female. For metric ports, NIST states that the inch is exactly 25.4 millimeters.[2] A converted number still has to match a real end. See how to measure a dust port and nominal vs actual hose sizes.
2. Read the listing's size for each end. A good maker page dimensions every end. POWERTEC lists its 70136 cone reducer at 3-61/64 inches OD and 3-41/64 inches ID on the 4-inch end,[3] and gives its 70147 adapter a 3.965-inch OD on the 4-inch end and a 2.26-inch OD on the 2-1/4-inch end.[4] Compare each figure with what you measured. "Universal" or "fits all" with no diameters is a reason to stop.
3. Check the seller. On Amazon, read "Ships from" and "Sold by" on the order page. Amazon's return policy says items shipped by third-party sellers go back to the seller rather than to Amazon.[5] A review saying a buyer ordered from a brand's Amazon store is one account, not proof that a seller is the brand.[6] We never call a marketplace seller "official." See ships from / sold by and seller of record.
4. Check returns before you order. Amazon says third-party sellers must offer a US return address, a prepaid label or a returnless refund, and that most items can be returned within 30 days of delivery, with exceptions.[5] That is Amazon's US page. On AliExpress, the current Free Returns terms say the return period is whatever the order page shows.[7] There is no single window to quote, so read the order page.
5. Check recalls. The CPSC says it is illegal to sell any recalled product,[8] and tells online buyers to search for recalls at cpsc.gov/Recalls.[9] Finding no recall is not proof of fit or safety. See CPSC recall.
How we earn and what we do not claim
We earn commissions from some links. The FTC says a website should disclose a commission relationship with a retailer clearly and conspicuously, and that the closer the disclosure is to the recommendation, the better.[10] So each page carries its own disclosure. The FTC also says you cannot talk about your experience with a product you have not tried.[10] We have not used these parts, so we report what makers state and never write as if we had.
How to choose
Use a finder to get the maker's stated size for what you own, measure to confirm, then buy a part whose maker dimensions both ends. These two approved parts show what a fully dimensioned listing looks like:
Picks that fit2 products
Choose POWERTEC's 70136 (4 in to 2-1/2 in cone reducer, single) only to join 4 in hose to 2-1/2 in hose; POWERTEC says it is not meant for equipment ports.
More on choosing
Choose POWERTEC's 70147 (4 in to 2-1/4 in tapered adapter, single) to step 4 in hose down to a 2-1/4 in port. Compare both ends with what you measured first. On Amazon, check that 'Ships from / Sold by' shows Amazon.com or POWERTEC.
4 in hose to a 2-1/4 in port or hose
Every page on measuring and buying
Guides
- How to measure a dust port
- Nominal vs actual dust hose sizes
- Buying dust-collection fittings online: a checklist
- Wood dust, fire and static: what OSHA and NFPA say
Finders
- Dust port finder by tool model
- Vacuum and collector inlet finder
- Dust hose size finder
- Duct fitting standard finder
Key terms
nominal size, tolerance, metric conversion, version code, maker claim, ships from / sold by and Free Returns.
Everything in this topic
Guides
- Buying dust-collection fittings online: a checklist before you orderGives you a short checklist to confirm sizes, seller, returns and recalls before ordering a dust fitting online.
- How to measure a dust port: inside or outside diameterHelps a reader record the two numbers that decide fit before buying any hose, adapter or cuff.
- Nominal vs actual dust hose sizes: why "2-1/2 in" does not mean 2.5 inHelps a reader stop matching parts by the label and start matching the two diameters that actually meet.
- Wood dust, fire and static: what OSHA and NFPA say, and what we do not coverShows what OSHA, NFPA and vacuum makers actually say about wood dust, fire and static, so you know where fit advice ends and the maker's manual begins.
Common questions
Is the Amazon seller the brand?
Not necessarily, so check. Read 'Ships from' and 'Sold by' on the order page. A listing that shows Amazon as the shipper does not tell you who sells it, and a third-party review that mentions a brand's Amazon store is not proof either. More in Buying dust-collection fittings online: a checklist before you order
Can I return a fitting that doesn't fit?
Usually, on the seller's terms. Amazon says most items can be returned within 30 days of delivery, with exceptions, and third-party items go back to the seller, who must offer a US return address, a prepaid label or a returnless refund. Read the order page before you buy. More in Buying dust-collection fittings online: a checklist before you order
Are AliExpress returns free?
Only for some items. AliExpress's Free Returns terms apply only to products with the Free Returns icon from sellers in the program, and the current terms say the return period is what the order page shows. More in Buying dust-collection fittings online: a checklist before you order
How do I check for a recall?
Search cpsc.gov/Recalls, as the CPSC tells online buyers to do. The CPSC says selling a recalled product is illegal. Finding no recall is not proof that a part fits or is safe. More in Buying dust-collection fittings online: a checklist before you order
Do I measure the inside or the outside of a dust port?
Both. Rockler advises measuring the inside and outside diameter of each port and hose connector, because the port's outside diameter has to match the hose's inside diameter. More in How to measure a dust port: inside or outside diameter
What tool do I use to measure a dust port?
A caliper is easiest: close the outside jaws across the widest point for the outside diameter and open the inside jaws for the inside diameter. A ruler laid across the center of the opening works if you read it carefully at the widest point. More in How to measure a dust port: inside or outside diameter
My port tapers. Which number do I use?
Record both the smallest and the largest diameter. Makers publish tapered ends as a range, for example POWERTEC lists the 4-inch end of its 70291 as tapering from 3.51 to 3.73 inches. More in How to measure a dust port: inside or outside diameter
Is 35 mm the same as 1-3/8 inches?
Not quite. One inch is exactly 25.4 mm, so 35 mm is about 1.378 inches and 1-3/8 inches is about 34.9 mm. That arithmetic does not make a metric part and an inch part interchangeable. More in How to measure a dust port: inside or outside diameter
Questions
Inside or outside diameter?
Both. Rockler advises measuring the inside and outside diameter of each tool port and hose connector, because the port's outside diameter has to match the hose's inside diameter. The measuring guide shows how.[1]
How do I know a listing's sizes are real?
Find the maker's own page for the part and compare. A listing that gives each end's size and matches the maker's page is a good sign; one that says only "universal" or "fits all" with no diameters is a reason to stop.
Who handles returns on Amazon third-party orders?
The seller. Amazon's return policy says items shipped by third-party sellers go back to the seller, who must offer a US return address, a prepaid label or a returnless refund. Most items can be returned within 30 days of delivery, with exceptions.[5]
Is the Amazon seller the brand?
Check; we never assume it. Read 'Ships from' and 'Sold by' on the order page. A third-party review that mentions a brand's Amazon store is not proof that a seller is the brand.[6]