# Fuel Tank Oops Fittings **URL:** \ **Category:** Everything Else\ **Created:** [March 28, 2026, 8:08pm UTC](https://sonexpilots.org/t/fuel-tank-oops-fittings/5531 "2026-03-28T20:08:16Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Kevin\_Conklin](https://sonexpilots.org/user_avatar/sonexpilots.org/kevin_conklin/32/1720_2.png) [@Kevin\_Conklin](https://sonexpilots.org/u/Kevin_Conklin)\ **Post date:** [March 28, 2026, 8:08pm UTC](https://sonexpilots.org/t/fuel-tank-oops-fittings/5531/1 "2026-03-28T20:08:17Z")
I am hoping that someone might be able to identify a source for the oops fittings. I could be wrong, but I doubt they are Sonex IP/engineered parts. ---
**Author:** ![ArtT568](https://sonexpilots.org/user_avatar/sonexpilots.org/artt568/32/2342_2.png) [@ArtT568](https://sonexpilots.org/u/ArtT568)\ **Post date:** [March 28, 2026, 8:23pm UTC](https://sonexpilots.org/t/fuel-tank-oops-fittings/5531/2 "2026-03-28T20:23:48Z")
I asked Grok AI the very same question. Here is the suggestion Grok provided. **Fabricate Your Own OOPS-Style Fitting** (Most Common Builder Approach) - Many builders have successfully made equivalents using basic machining or hardware store/lathe work. - **Basic design** (matches Sonex instructions): - Materials: 6061 aluminum bar stock for the boss; standard nuts/washers. - Key dimensions from Sonex docs: Drill hole to ~1" final for the 3/8 NPT version; use a Viton O-ring compatible with 100LL (replacement O-rings were SNX-G01-33). - Builders often add a groove for the O-ring on the internal piece and sometimes make a custom spanner or backing plate for better clamping. - If you (or a friend/local machine shop) have access to a lathe, this is straightforward and inexpensive. Several forum threads show photos of homemade versions that have held for years. ---
**Author:** ![WesRagle](https://sonexpilots.org/user_avatar/sonexpilots.org/wesragle/32/1450_2.png) [@WesRagle](https://sonexpilots.org/u/WesRagle)\ **Post date:** [March 29, 2026, 4:37pm UTC](https://sonexpilots.org/t/fuel-tank-oops-fittings/5531/3 "2026-03-29T16:37:59Z")
Hi Kevin, Here is a source for plastic “Oops Fittings”. Might be worth evaluating. [Bulkhead Fittings](https://www.usplastic.com/search/?q=bulkhead%20fittings). _ **Edit:** _ They have metal ones too. [Banjo® 316 Stainless Steel Bulkhead Fittings with EPDM Gaskets](https://www.usplastic.com/catalog/item.aspx?itemid=91018&clickid=search). And more from Zoro. [Bulkhead Tank Fitting](https://www.zoro.com/banjo-bulkhead-tank-fitting-epdm-1-38l-ss-tf038ss/i/G407968948/?msclkid=386fce0e20da17ee83d9a7c7768b3702&utm_source=bing&utm_medium=cpc&utm_campaign=ml_all_na_na_ssc_Bing%20cost%20per%20sale%20test%20(CPS)&utm_term=4586681479489829&utm_content=Cost%20per%20sale%20test%20Bing&gclid=386fce0e20da17ee83d9a7c7768b3702&gclsrc=3p.ds&gad_source=7&gad_campaignid=20511323246). We should be able to find something suitable. Wes ---
**Author:** ![Kevin\_Conklin](https://sonexpilots.org/user_avatar/sonexpilots.org/kevin_conklin/32/1720_2.png) [@Kevin\_Conklin](https://sonexpilots.org/u/Kevin_Conklin)\ **Post date:** [March 29, 2026, 6:56pm UTC](https://sonexpilots.org/t/fuel-tank-oops-fittings/5531/4 "2026-03-29T18:56:36Z")
Good find. Could work. Looks like the fittings that Sonex sold had a o-ring vs these that have a thicker rubber piece. Also, Sonex sold them for \<$30, and no amount of buying in bulk will get the cost down from $90+ to that price. ---
**Author:** ![ronvoss](https://sonexpilots.org/letter_avatar_proxy/v4/letter/r/6de8d8/32.png) [@ronvoss](https://sonexpilots.org/u/ronvoss)\ **Post date:** [March 30, 2026, 12:06am UTC](https://sonexpilots.org/t/fuel-tank-oops-fittings/5531/5 "2026-03-30T00:06:09Z")
I checked my inventory and have 5 of the small !/8” fpt oops fittings that came with my latest project purchase. The builder was a machinist and made these. If anyone needs any of these, let me know. ![20260329_152140](https://sonexpilots.org/uploads/default/original/2X/d/d23760c59cc11164414f19cdba42233f066df127.jpeg) ---
**Author:** ![WesRagle](https://sonexpilots.org/user_avatar/sonexpilots.org/wesragle/32/1450_2.png) [@WesRagle](https://sonexpilots.org/u/WesRagle)\ **Post date:** [March 30, 2026, 12:28am UTC](https://sonexpilots.org/t/fuel-tank-oops-fittings/5531/6 "2026-03-30T00:28:48Z")
Hi Ron, I could use one. I looked back at my build and I did replace all three of the main fittings. One of them ended up with a fuel level probe. So, I need one more. I’ll PM you. ![P1020614](https://sonexpilots.org/uploads/default/original/2X/7/7a16ef577a64e57efd782013b4b066a126712ece.jpeg) ![P1020640](https://sonexpilots.org/uploads/default/original/2X/c/c3ed72c09ca4c7f8fc8eeb1457cdb9d4447836b8.jpeg) Wes ---
**Author:** ![Kevin\_Conklin](https://sonexpilots.org/user_avatar/sonexpilots.org/kevin_conklin/32/1720_2.png) [@Kevin\_Conklin](https://sonexpilots.org/u/Kevin_Conklin)\ **Post date:** [March 30, 2026, 12:56am UTC](https://sonexpilots.org/t/fuel-tank-oops-fittings/5531/7 "2026-03-30T00:56:16Z")
I know Sonex had a 1/8”, 1/4”, and 3/8” - I don’t even know yet if I need one of each - or what exactly. Bu I would like to get at least one of the 1/8” ones you have. I’ll PM also. ---
**Author:** ![WesRagle](https://sonexpilots.org/user_avatar/sonexpilots.org/wesragle/32/1450_2.png) [@WesRagle](https://sonexpilots.org/u/WesRagle)\ **Post date:** [March 30, 2026, 1:05am UTC](https://sonexpilots.org/t/fuel-tank-oops-fittings/5531/8 "2026-03-30T01:05:11Z")
HI Kevin, This might help. [SNX-G02 Fuel Tank Fittings Installation](https://www.sonexaircraft.com/documents/plan_sheets/SNX-G02_B_Fuel_Tank.pdf). Wes. ---
**Author:** ![Kevin\_Conklin](https://sonexpilots.org/user_avatar/sonexpilots.org/kevin_conklin/32/1720_2.png) [@Kevin\_Conklin](https://sonexpilots.org/u/Kevin_Conklin)\ **Post date:** [March 30, 2026, 1:39am UTC](https://sonexpilots.org/t/fuel-tank-oops-fittings/5531/9 "2026-03-30T01:39:07Z")
Thanks. It looks to me (if no sight tube is used), it would take (2) 1/8” fittings, and (1) 3/8” fitting. I don’t see any reference to a 1/4” fitting - I guess that would be for a custom/extra application. ---
**Author:** ![JKS](https://sonexpilots.org/letter_avatar_proxy/v4/letter/j/bb73d2/32.png) [@JKS](https://sonexpilots.org/u/JKS)\ **Post date:** [March 30, 2026, 12:55pm UTC](https://sonexpilots.org/t/fuel-tank-oops-fittings/5531/10 "2026-03-30T12:55:22Z")
# **Summit Racing™ Fuel Cell Bulkhead Adapter Fittings SUM-220882B** 4.5 out of 5 stars [( 7 )](https://www.summitracing.com/parts/sum-220882b/reviews) Part Number: **SUM-220882B** **$13.99** **[Summit Racing™ Fuel Cell Bulkhead Adapter Fittings](https://www.summitracing.com/search/part-type/bulkhead-fittings/product-line/summit-racing-fuel-cell-bulkhead-adapter-fittings)** Fitting, Fuel Cell, Male Bulkhead, -8 AN, Aluminum, Black Anodized, Each **[See More Specifications](https://www.summitracing.com/parts/sum-220882b#overview)** Various sizes ---
**Author:** ![Bryan\_Cotton](https://sonexpilots.org/user_avatar/sonexpilots.org/bryan_cotton/32/760_2.png) [@Bryan\_Cotton](https://sonexpilots.org/u/Bryan_Cotton)\ **Post date:** [March 30, 2026, 1:38pm UTC](https://sonexpilots.org/t/fuel-tank-oops-fittings/5531/11 "2026-03-30T13:38:57Z")
That looks pretty promising. ---
**Author:** ![Kevin\_Conklin](https://sonexpilots.org/user_avatar/sonexpilots.org/kevin_conklin/32/1720_2.png) [@Kevin\_Conklin](https://sonexpilots.org/u/Kevin_Conklin)\ **Post date:** [March 30, 2026, 3:22pm UTC](https://sonexpilots.org/t/fuel-tank-oops-fittings/5531/12 "2026-03-30T15:22:03Z")
Those look like they could be an option. On the positive side, those are AN fittings - better than fuel system applications than the NTP thread fittings that were on the Sonex supplied fittings. Also, those PTFE washers look like they might have a better chance of a leak free seal than the o-ring on the Sonex version. But … 1. How would you tighten the fitting if you can’t get to the inside of the tank to hold that inside hex in place? The Sonex supplied version has the flats on the end of the NTP threaded section to hold the whole unit while you tighten the nut. 2. If there is a way to hold the whole fitting and tighten the nut, what would be the AN equivalent sizing to the 1/8”, 1/4”, 3/8” Sonex fitting sizes? I found this: “… the following NPT Port to AN adapters will provide a common I.D. through hole: **Maximum AN line for NPT port size:** 1/4” NPT is compatible with up to -6 AN (3/8” hard line) 3/8” NPT is compatible with up to –8 AN (1/2” hard line) …” ---
**Author:** ![Kevin\_Conklin](https://sonexpilots.org/user_avatar/sonexpilots.org/kevin_conklin/32/1720_2.png) [@Kevin\_Conklin](https://sonexpilots.org/u/Kevin_Conklin)\ **Post date:** [March 30, 2026, 3:42pm UTC](https://sonexpilots.org/t/fuel-tank-oops-fittings/5531/13 "2026-03-30T15:42:44Z")
> [@Kevin\_Conklin](#): > > How would you tighten the fitting if you can’t get to the inside of the tank to hold that inside hex in place? Just spitballing here on this question: 1. Using a crowsfoot wrench with an extension to hold the fitting on the inside of the tank; or 2. Since AN threads are straight, ‘double nutting’ (making sure not to overdo it and stretch the threads at all) after getting the fitting’s nut in place. I wouldn’t expect a high torque on the fitting nut itself would be required. ---
**Author:** ![Bryan\_Cotton](https://sonexpilots.org/user_avatar/sonexpilots.org/bryan_cotton/32/760_2.png) [@Bryan\_Cotton](https://sonexpilots.org/u/Bryan_Cotton)\ **Post date:** [March 30, 2026, 3:46pm UTC](https://sonexpilots.org/t/fuel-tank-oops-fittings/5531/14 "2026-03-30T15:46:44Z")
Double nutting sounds like a good idea. We could also make a tool that would expand inside the fitting and clamp inside it. I would choose the fitting to match the line and not worry about the Sonex equivalent. The one thing to consider, you need to drill out all of the original molded fitting. So if you install an AN6 fitting, is the OD big enough? ---
**Author:** ![13brv3](https://sonexpilots.org/user_avatar/sonexpilots.org/13brv3/32/695_2.png) [@13brv3](https://sonexpilots.org/u/13brv3)\ **Post date:** [March 30, 2026, 5:10pm UTC](https://sonexpilots.org/t/fuel-tank-oops-fittings/5531/15 "2026-03-30T17:10:04Z")
Where there’s a will, there’s a way, but those Summit bulkhead fittings just aren’t quite what we need. Close though, and a good thought. Rusty ---
**Author:** ![Kevin\_Conklin](https://sonexpilots.org/user_avatar/sonexpilots.org/kevin_conklin/32/1720_2.png) [@Kevin\_Conklin](https://sonexpilots.org/u/Kevin_Conklin)\ **Post date:** [March 30, 2026, 7:16pm UTC](https://sonexpilots.org/t/fuel-tank-oops-fittings/5531/16 "2026-03-30T19:16:54Z")
Ah - just realized that with those Summit fittings, the nut would be on the inside of the tank and the AN treads/fitting/port on the outside. So yeah, that won’t work. ---
**Author:** ![Bryan\_Cotton](https://sonexpilots.org/user_avatar/sonexpilots.org/bryan_cotton/32/760_2.png) [@Bryan\_Cotton](https://sonexpilots.org/u/Bryan_Cotton)\ **Post date:** [March 30, 2026, 7:44pm UTC](https://sonexpilots.org/t/fuel-tank-oops-fittings/5531/17 "2026-03-30T19:44:24Z")
> [@Kevin\_Conklin](#): > > So yeah, that won’t work. I missed that before. I think if we have a good drawing, they would not be hard to make on the lathe. ---
**Author:** ![sonex1517](https://sonexpilots.org/user_avatar/sonexpilots.org/sonex1517/32/609_2.png) [@sonex1517](https://sonexpilots.org/u/sonex1517)\ **Post date:** [March 30, 2026, 7:58pm UTC](https://sonexpilots.org/t/fuel-tank-oops-fittings/5531/18 "2026-03-30T19:58:25Z")
Hi Ron I definitely need one if any are left. thanks ---
**Author:** ![ronvoss](https://sonexpilots.org/letter_avatar_proxy/v4/letter/r/6de8d8/32.png) [@ronvoss](https://sonexpilots.org/u/ronvoss)\ **Post date:** [March 31, 2026, 1:32am UTC](https://sonexpilots.org/t/fuel-tank-oops-fittings/5531/19 "2026-03-31T01:32:12Z")
Kevin, let me know address to ship to and I will check on shipping. ---
**Author:** ![ronvoss](https://sonexpilots.org/letter_avatar_proxy/v4/letter/r/6de8d8/32.png) [@ronvoss](https://sonexpilots.org/u/ronvoss)\ **Post date:** [March 31, 2026, 1:33am UTC](https://sonexpilots.org/t/fuel-tank-oops-fittings/5531/20 "2026-03-31T01:33:36Z")
Let me know address and I will check on shipping. Looks like 3 will be sold and I will have 2 left. [Next page](https://sonexpilots.org/t/fuel-tank-oops-fittings/5531.md?page=2)