12 pt for aviation?

[Jure]

few days ago on my club's PA18 two techs were making the 100 hour inspection and i have noticed they were both using ALL 12 pt sockets,1/4 and 3/8 12 pt. also few weeks ago i have noticed the same thing but in that case the other tech was working on the plane... why they are using only 12 pt stuff? only reason i can see is limited space so its easier to fit on the fastener,but again not all over the engine and as far AS I know there is no 12 pt fasteners on small planes like super cub,but i may be wrong. and worst of all i asked the tech why aviation technicians are using 12 pt's and his answer was "i have no idea,everyone is using 12 pt so it was the reason why i went with 12pt" i'm sure we have a few aviation tech's here on the board,so lets see the answer

 

[paranoid56]

i know last time i was looking at a plane all the dame fasteners were 12pt. I have a few friends and they normally also carry only 12pt sockets as he said 90% of the stuff they work on is 12pt and for that other 10% a 12pt socket works fine.

i had to go actually buy some 12pt sockets to work on a engine for my car as the PO used a bunch of 12pt bolts and i gave my 12pt stuff away long ago lol

 

[bob15]

What is wrong with using 12 point sockets? Is it a crime now????

 

[Verg]

you see 12 point and spline fasteners in aerospace components because they allow for more accurate torquing of fasteners. more points of contact = better torque transfer.

 

[Jure]

What is wrong with using 12 point sockets? Is it a crime now????

nothing wrong,i would never go with 6 pt swivel sockets...i have both 12 and 6 pt sockets,but thread was not about which is better 6 pt or 12 pt (you can see that kind of thread here on a daily base lol),i was just asking why they are using 99% 12 point sockets...

 

[Dave455]

All other things being equal, you are better off using 12 point!

They are quicker to put over the fastener, and if you are using say a sliding T handle in limited space, you will only have to turn the socket through half the angle before you remove it!

Small points, but they matter! Bear in mind that the servicing of aviation components is often worked out in minute detail, so if the designer factored in that a certain component would be removed with a 12 point socket and a 12 inch breaker bar, there may not be room to turn a 6 point!

Bear in mind also, the increasing number of fasteners that need 12 point sockets (not spline - they are different again) and you will see why the aviation guys choose 12 point first!

Of course, all things are not equal, and the main reason why aviation guys use 12 point sockets is that they can! Most aerospace fasteners are top quality, and you won't round them off using 12 point!

We, on the other hand, have to work with 'soft as ****' fasteners outsourced to wherever is cheapest, and we have to use 6 point to prevent rounding!

As a matter of interest, I don't think my Dad ever owned a 6 point socket! He had old cars with decent fasteners, and never needed them!

 

[Stuart in MN]

I would imagine A&P mechanics don't have to deal with rusty, beat up nuts and bolts like you would find on a car or truck. If they can do everything with 12 point sockets, it saves the cost of buying 6 point sockets.

 

[paul2112]

Most everything at wrk is 12 point,,,some 6 but mostly 12...777, 757,md80,737,767,787,scarebus,

 

[jdpflyer]

I've worked on planes from ultralights to 747s for the past 35 years. Large aircraft engines and components are covered with 12 point fasteners. Small aircraft usually have 6 point fasteners with some of the components having a few 12 point fasteners. I personally prefer 6 point sockets where I can use them.

Jimmy

 

[tlpatter]

As an A&P tech during school, and now at work 6 pt was never required. Due to the fact that corrosion is generally dealt with in the early stages and the frequency of inspections that aircraft that are in service go through hardware is generally kept in pretty good condition. Also youre always trying to get to something in a tight spot so 12 pt is better.

 

[Farmall450]

12 point fasteners...planes won't see salt, so it is correct that corrosion isn't as extreme as some Midwest vehicles.

 

[mattygee]

In aviation, either general or commercial, 12 point fasteners show up often enough you may as well buy 12 point as your main selection. I have full sets of 12 point, with select 6point sockets/wrenches for situations where 12 point is not ideal.

 

[Airframer]

Simple. Lots of 12 point fasteners. We're a practical lot.

 

[Danny Gooding]

On turbine engines, PT6 or JT15D's they are almost exclusively 12 point fasteners. 12 point still works on 6 point, but not vise versa.

 

[wild cowboy]

It is interesting that you see a lot of Koken tools (which I love) being used by aircraft mechanics working on multimillion dollar aircraft, yet you never see auto mechanics use them - and yet the auto mechanic's hand tools may have actually been more expensive, strange!

 

[Jure]

It is interesting that you see a lot of Koken tools (which I love) being used by aircraft mechanics working on multimillion dollar aircraft, yet you never see auto mechanics use them - and yet the auto mechanic's hand tools may have actually been more expensive, strange!

pretty much all of them are using stahlwille here in my country

 

[Farmall450]

It is interesting that you see a lot of Koken tools (which I love) being used by aircraft mechanics working on multimillion dollar aircraft, yet you never see auto mechanics use them - and yet the auto mechanic's hand tools may have actually been more expensive, strange!

It's Cman and SO at O'Hare.
Throw in the other tool trucks for good measure.

 

[Ruger_556]

It is interesting that you see a lot of Koken tools (which I love) being used by aircraft mechanics working on multimillion dollar aircraft, yet you never see auto mechanics use them - and yet the auto mechanic's hand tools may have actually been more expensive, strange!

Wow, that has nothing to do with the OP, good job Get tired of your own threads getting locked or what?

 

[espyking83]

Fasteners on planes dont get as crusty nor are they torqued as high as they would be in other professions. 6 point really isnt warranted unless you're wiping someones ***.

 

[pipsters]

On a side note are you A&Ps seeing any metric 12 point or is almost all SAE? I'm talking GA mostly but also 121.

I'm typed in the CL65 and A320.

 

[Ruger_556]

On a side note are you A&Ps seeing any metric 12 point or is almost all SAE? I'm talking GA mostly but also 121.

I'm typed in the CL65 and A320.

I'm kinda curious about that too... Only metric head 12 point I've ever run across was a 12 mm.

 

[espyking83]

In 8 years of aviation maintenance I've only seen one metric fastener, it was on a mod and you could tell that it clearly wasnt supposed to be there.

 

[Jure]

finally i got the answer why they are using 12 pt instead of 6

 

[flynlow8740]

There are a few metric fasteners, mostly on accessories adapted from automotive, such as AC compressors. Aviation hardware is small, I've never needed 6 point, except for the occasional exhaust stud.


Sent from my iPad using Tapatalk

 

[BK13]

pretty much all of them are using stahlwille here in my country

Interesting. I would have thought there would have been a mix of Stahlwille, Hazet, and Gedore...

 

[IndyGarage]

Aviation generally uses 12 point fasteners or socket head capscrews.

They are 12 point so you can differentiate them from standard fasteners.

Aviation fasteners are made of a higher grade of steel and they are heat treated, not just work hardened from roll forming. They are much more expensive than standard hardware.

They supposedly will tear up soft tools - when I worked in an engine factory, most all the mechanics said they couldn't use craftsman tools because they would literally wear out from contact with the hardened bolts. Of course there was one old guy who proved them wrong - he was still using the same craftsman set he bought when he started 35 years earlier.

 

[SawtoothJL]

Our Aerosapitale (Now Airbus Helicopter) is exclusively 12 pt Metric

 

[jensputzier]

Interesting. I would have thought there would have been a mix of Stahlwille, Hazet, and Gedore...

Stahlwille's largest customer is Airbus. AFAIK they even have one of their distribution centers there. Stahlwille is very strong in aviation.

 

[ZRX61]

It's Cman and SO at O'Hare.
Throw in the other tool trucks for good measure.

In the military I noticed that the RAF use SnapOn while the USAF use Craftsman (mostly).

 

[bob15]

It is interesting that you see a lot of Koken tools (which I love) being used by aircraft mechanics working on multimillion dollar aircraft, yet you never see auto mechanics use them - and yet the auto mechanic's hand tools may have actually been more expensive, strange!

Pratt Whitney jet engines: Bonney and Snap On

 

[Spyder1gdsm]

I'm still active duty and haven't ever used a craftsman at work. It's been all Snap On for all of our tools and that's multiple bases and airframes.

 

[Jure]

Stahlwille's largest customer is Airbus. AFAIK they even have one of their distribution centers there. Stahlwille is very strong in aviation.

yep,they are. but alot of tech's are complaining on stahlwille,they said ratchet quality went downhill...i may be wrong but i think airbus moved on facom

 

[Wamsutta]

AS I know there is no 12 pt fasteners on small planes like super cub,but i may be wrong.

If those A&P techs ever get a business jet in the hanger, it'll probably have some 12-point hardware.

 

[SawtoothJL]

yep,they are. but alot of tech's are complaining on stahlwille,they said ratchet quality went downhill...i may be wrong but i think airbus moved on facom

I wouldn't be surprised at all if facom now supplies Airbus.

 

[Jure]

yes,Airbus moved on facom!

 

[BK13]

I'm still active duty and haven't ever used a craftsman at work. It's been all Snap On for all of our tools and that's multiple bases and airframes.

Thank you for your service, sir!

 

[riscoe]

Working on corporate jets, commuters-
I use both 6 and 12 pt. Most turbine engines have a majority of 12 pt. I've never rounded a 12 pt out, though I suppose it's possible. As previously mentioned, the 12 pt fasteners are pretty robust. Airframe components generally have 6 pt, but not always.
When I first started out I could only afford one set of swivels, so they were 12pt, and I still use them quite often.
As far as corrosion goes, its true, most aircraft inspection intervals keep the majority of corroded fasteners in check, but I seem to run in to numerous frozen fasteners installed into flight control sectors, bellcranks, rod ends etc. on some airframes with 6k-10k hours. I've rounded out and snapped off some 6 pt AN bolts many times.
But not the 12 pt- I've broken at least a half dozen Snap-on 9/16 12pt swivels dropping the accessory gearbox off of Rolls Royce AE3007c engines. I broke 2 once on one engine. The SO driver didn't like me much that day.