AN fittings & hinges
AN818 Coupling Nut (B-Nut)
The nut of a flared tube joint, in steel, aluminum and stainless.
- StandardAN818 (= MS20818)
- FormCoupling nut for flared tube
Where to buy
AmericaDistributor coming soonOur partner for this region is on its way
EuropeDistributor coming soonOur partner for this region is on its way
OceaniaDistributor coming soonOur partner for this region is on its way
More distributors
AmericaMore distributors coming soon
EuropeMore distributors coming soon
OceaniaMore distributors coming soon
The dash number is the tube outside diameter in sixteenths (−4 = 1/4"). A "D" suffix is aluminum, "J" stainless, no suffix steel, as the listing's columns show.
It works with the AN819 sleeve behind the flare. Our roadmap covers AN fitting sizes in a chart page.
Specifications
| Standard | AN818 (= MS20818) |
|---|---|
| Form | Coupling nut for flared tube |
Source: a distributor's listing, checked 2026-09-30.
Sizes listed 9 rows
| Steel | Aluminum | Stainless | Tube OD (in.) | Thread |
|---|---|---|---|---|
| 2 | 2D | 2J | 1/8 | 5/16-24 |
| 3 | 3D | 3J | 3/16 | 3/8-24 |
| 4 | 4D | 4J | 1/4 | 7/16-20 |
| 5 | 5D | 5J | 5/16 | 1/2-20 |
| 6 | 6D | 6J | 3/8 | 9/16-18 |
| 8 | 8D | 8J | 1/2 | 3/4-16 |
| 10 | 10D | 10J | 5/8 | 7/8-14 |
| 12 | 12D | 12J | 3/4 | 1-1/16-12 |
| 16 | 16D | 16J | 1 | 1-5/16-12 |
Questions people actually ask
Where can I buy the AN818 Coupling Nut?
A distributor we checked lists it in the Americas. The link to its page, with the live price and stock, opens when the partnership does.
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