Welding Tips and Tricks

Good evening,

I discovered that I need to have possible TIG repairs made to a nose strut metering pin's threads. In the nose strut at the FAA shop, I see that the threads have been damaged by age, corrosion, someone forcing the nut off rather than using finesse. At this point, its anyones guess as to what caused the threads to strip.

Since the cost of the part is absolutely ridiculous, at $3800.00, I am curious as to the possibility to replace the missing metal via a TIG repair and then have the threads re-cut. Any FAA certified welders care to weigh in on this and any recommendations where I can have this done?

Thanks for taking the time to read my post.

Cheers
Trevor

1967 Cessna 150G

Call me chickensh^t, wussy, etc........I wouldn't touch an airplane part with a 10ft torch. Guys that are certified, etc, they still must worry about the "what if" factor. Dunno, maybe it's just me?

Last I heard, FSDO and GADO FAA maintenance guys could not issue field approvals related to landing gear items. You will probably have to find a DER with the appropriate certs to write up a proceedure. Guessing the paperwork will cost about 1/2 as much as the new part.

I know when they had to write a new procedure for a boiler repair I did it cost a little over $2000. Because of the paperwork and the time to make weld samples that get tested for the certification process. Obviously not airplane grade but I’d imagine the process is about the same.

There is no way a DER would sign off on that type of repair. He would need to know the exact composition of the bolt either through analysis or the original drawings. The part would need heat treating after re machining the threads. If it is off a 150 just give White Industries a call and get a serviceable used part.

Bill
Wichita, KS

Thanks guys for your responses. All very valid points. In fact, in looking closer at the part, I am thinking the top has been machined at some point in its past. Color difference and a beveled edge where every reference I have pulled on line doesn’t have that particular cut.[emoji848]

The hunt for a serviceable part has begun.


Sent from my iPhone using Tapatalk

discap wrote:There is no way a DER would sign off on that type of repair. He would need to know the exact composition of the bolt either through analysis or the original drawings. The part would need heat treating after re machining the threads. If it is off a 150 just give White Industries a call and get a serviceable used part.

Bill
Wichita, KS

Bill,

Thanks! That place looks awesome. Having their own runways is off the hook. Wichita, KS..... the Mecca of Cessna.



Sent from the cat

Luckily, I just found a viable replacement at our local aviation wrecking yard. Yup, we have one here is Sacramento. It’s the same yard the Mythbuster team got all of their aviation items for all the aviation myths. Chicken gun, spiral cut wing, etc.

Anyway, for the most part, it’s identical with the exception that it’s about 1/4” longer. Although, in taking a closer look, it seems that my original might have been machined sometime in its past. It’s all about the journey, right?




Looks like the original might have been machined a bit.

Original


Replacement



Sent from my iPhone using Tapatalk

Dup

Possible it was just a part change as time progressed.

That is exactly what happened. In reading through the service manuals for the 100 series aircraft, our particular year was where they made some changes. Literally the prior year had two possible setups and with the 1967 year, shortened the metering pin slightly as well as changed the small collar at the very bottom just above the large hexagon nut. In cross referencing the actual part number, I was able to find a single image of a pin being sold from the Texas Air Salvage that showed the same beveled edge.

I located at precision machine shop here locally. When I visited, I was surprised at the size of the operation as well as the machinery. The name is Airpoint Precision. In speaking with the lathe dept manager, he has a tech that is an A&P and will have him turn it down after looking at the pin.

Fingers crossed[emoji1695]


Sent from my iPhone using Tapatalk

There’s got to be plenty of 150Gs in salvage yards to get the right part. A better bet may be to get the entire strut. When I’ve seen airworthy 150s go for $10k lately, you could buy a whole plane for not much more than Textron wants for that part.

All that said, welding that up with 309 wire and turning new threads wouldn’t be a big deal. Not much pressure in the 150 nose strut. The question is have, were the threads cut or rolled? I don’t think I’d have a problem issuing an 8110-3 for it.


Sent from my iPhone using Tapatalk

dgapilot wrote:There’s got to be plenty of 150Gs in salvage yards to get the right part. A better bet may be to get the entire strut. When I’ve seen airworthy 150s go for $10k lately, you could buy a whole plane for not much more than Textron wants for that part.

All that said, welding that up with 309 wire and turning new threads wouldn’t be a big deal. Not much pressure in the 150 nose strut. The question is have, were the threads cut or rolled? I don’t think I’d have a problem issuing an 8110-3 for it.


Sent from my iPhone using Tapatalk

Thanks DGA

You think it would be easy,

However, I guess I have a knack for acquiring the odd-ball items. In going through most of the front fork sections, the one I grabbed was the closest I could find. That said, the one I wanted was probably in the remaining 10% I didn’t inspect.

The shop did offer to make a completely new identical items out of harder material like the original for substantially less than the price of a new one[emoji1].



Sent from my iPhone using Tapatalk

Picked the part up and they were able to machine everything to the specks I asked. I presented the part to the A&P resealing the nose strut and he then proceeds to point out another area that need to be milled .03” and tells me it will have hydrologic lock if it’s not corrected.

Original on the top, machined part on the bottom.


Machined collar on replacement part


Original collar


Ok, I get it, but I honestly feel he is now F-ing with me because it’s a point not consulted with on his first rejection. Another delay of two weeks. All I ask it tell me everything that needs to be addressed. He then attempts to lecture me how “us” airplane owners want to save a buck. Seriously, on a $3,800.00 part that his shop mongoed off rather than properly loosening the nut. Which I can not prove.

And folks ask me why I want to go to the trouble of getting my A&P so I can do this myself.....legally.


Sent from my iPhone using Tapatalk

Get your A&P, then go for the IA; you can inspect your own work.

JT68912 wrote:Picked the part up and they were able to machine everything to the specks I asked. I presented the part to the A&P resealing the nose strut and he then proceeds to point out another area that need to be milled .03” and tells me it will have hydrologic lock if it’s not corrected.

Original on the top, machined part on the bottom.


Machined collar on replacement part


Original collar


Ok, I get it, but I honestly feel he is now F-ing with me because it’s a point not consulted with on his first rejection. Another delay of two weeks. All I ask it tell me everything that needs to be addressed. He then attempts to lecture me how “us” airplane owners want to save a buck. Seriously, on a $3,800.00 part that his shop mongoed off rather than properly loosening the nut. Which I can not prove.

And folks ask me why I want to go to the trouble of getting my A&P so I can do this myself.....legally.


Sent from my iPhone using Tapatalk

Keep in mind that when an A&P IA signs off on your aircraft he is taking on a significant amount of liability/risk. He has no control over what Textron charges for a part, and under Part 43, he is required to install parts that are “airworthy”. To be honest, installing the modified part without engineering approval to him is a risk. Each A&P has his own level of risk acceptance. Be glad he is even willing to use the modified part without a DER approval. He could well have said the right part or no signature.


Sent from my iPhone using Tapatalk

Don't ask from Ajax, he's an impostor. G. Gordon Liddy

Liddy learned to fly at A little airport that was in Red Hook NY, just north of Rhinebeck. He was assistant DA for Dutchess County at the time. I guy I worked with was his flight instructor.


Sent from my iPhone using Tapatalk

dgapilot wrote:Liddy learned to fly at A little airport that was in Red Hook NY, just north of Rhinebeck. He was assistant DA for Dutchess County at the time. I guy I worked with was his flight instructor.


Sent from my iPhone using Tapatalk

Click on the hyperlink in my post.