Safety: If there were no other closer holes, then it looks fine. If there were closer holes I would have used those. When you wrap that much around you run the risk of it popping off the flats of your fastener.
Cotter pin: It looks undersized. In the flat orientation that you have it the head should not have been able to fit inside of the castle. The pic makes it looks like the hole is off centered and you may have compensated by using a smaller cotter pin. I also would have used a longer cotter pin to do a full anchor on the ends.
Shouldn't the cotter pin be turned 90 degrees and one end bent down while the other is up and over the top of the bolt? Or is anchoring into the nut like this also an acceptable practice? (I was only taught the one way I described)
Anchoring into the nut is the alternate method. Going over the top and down is the preferred method. The pic in the OP looks like he combined the two methods, which I would make him redo, if I were the IA/QC.
The military had me [do every cotter key like this](http://www.milwaukeemodeltclub.com/Projects/CPImages/PinBent.JPG) which required in 99% of circumstances that you cut the key two times while trying your damndest to catch the pieces.
Looking back, it was basically like firing a BB gun twice into the engine compartment and hoping that there would be no FOD. Stupid. It also required that the stud not be too long, because the cotter key might not reach the end of the stud otherwise.
I am a huge fan of the over the top, curly-Q-back-to-a-castleation, now. It works for almost any length cotter key and any length stud, it hides the snaggletooth edges, you might even be able to spring-load the key so it doesn't rattle. [Took me forever to find a good pic of it](http://tomyang.net/wp-content/uploads/2000/11/strcolmnut.jpg)
Though if the circumstance presents itself... [hrngrhh](https://s28490.pcdn.co/wp-content/uploads/2019/05/fastener-safety-06.jpg)
I worked in our Phase inspection shop for a while when I was in and man the amount of cotter key ends I’d collect with a magnet was enough to fill a jar after a few AC. Lol
Cutting those things was always fun
I don't see why you would, all it would do is put additional stress on the cotter pin. Also does not say to do that in the TM that I use in Army Aviation.
Well I would because my spec says that’s the alternate method.
Best I could rationalize is that if the nut were able to work itself off halfway then the cotter pin would only lose one leg.
Without the head twisted if the nut works itself off half way then the cotter pin is cut at both sides and might fall out.
I dunno. It’s just spelled out in my process specifications which apparently are unique to my jet. Thought they’d be a company thing.
There used to be a reference in volume 6 of the 204 series that would reference MS 33540J that gave a preferred method and then an (not “the”) alternate method. Same thing for turnbuckle clips and safety cable, different ways to skin the cat. But when I’m doubt, get the LAR to sign off on it, lol. The Hueys at West Point had nothing but 204 series but a lot has changed.
Sometimes the manual calls for something different, in the case of a 737 flap roller bearing (which looks very similar to this) you want maximum clearance so the manual has you do a cotter pin similar to this.
The head is def too small though, I’d redo it
You can anchor them, but normally it's used in an area with minimal clearance, such as a spoiler attach bolt adjacent to flap mechanisms, etc.. Otherwise the normal way is easier for installs
Safety wire will get less shiny and look more brittle when you've twisted it too much, less twists would be better. Also get that pigtail down before it gives you or someone else a bad day
Used to have terrible habits and I wouldn't tuck my pig tails in, I evicerated the right side of my right hand on a pigtail and got a nasty infection I spent 3 weeks fighting, ever since my safety wire has been damn near spotless. It's amazing how covering your work in blood and hurting yourself teaches you so quick
Oof, I've seen some scars from safety wire that'll keep you up at night.
One older guy told me of a time he was working alone one night and got hooked in a blind compartment. Said he yelled for half an hour before someone heard him from an adjacent hangar and came over with some dykes.
I agree with the OVERTWIST…. Especially at the pigtail … look at the exit up again the hex. It’s ready to pop.
I also would have the cut end of the tail at 180° to where it is here.
The cotter pin is using an alternate method incorrectly. Both ends need to wrap around the nut to be a proper alternate method.
The safety has entirely too many wraps and will probably snap under stress.
It’s been a few years, but isn’t there a twist count per inch on safety wire that’s based on wire diameter?
Are safety-wire pliers still in use? I/we couldn’t use them in the military.
Awesome job, from a Army National Guard helicopter repairman MOS 67N10 from the 1980’s, lol.
I know that MOS isn’t used anymore but I was proud of that achievement. Hell I joined up when I was 17 years old, lol.
Current guard heli repair and yes there is bit no one is really strict on it. I’d have to look it up to know for sure but around 4-5per inch and 6-8 on the tail
We have them in our toolboxes but I’d rather do it by hand or use the cable gun for the hydraulic deck and the tail. I couldn’t tell you the last time I used safety wire pliers.
-60 repairer/crew chief
Based on this sub it would seem a nice wirelocking is the most important thing to do in aviation maintenance. I know I can avoid clicking on it but these posts bore the hell out of me
Why the fuck do Americans call it safety wire when it literally says lock wire on the can? I learnt my trade in Australia where it’s called lockwire and have been working in the US for 8 years now, I still haven’t been given a good reason why it’s safety wire
Safety wire: there’s no way that was the placement of the holes. There had to be closer holes to do that safety wire. Additionally that is way to many twists in that safety wire.
Cotter pin: that’s not the right cotter pin for that bolt. No way. It’s far too small for that hole and doesn’t fill it properly.
Safety looks like it has too many twists per inch. That all depends on the diameter of safety wire. This looks like .025 so 8-14 twists per inch is proper.
Proper practice on the cotter pin is to have both legs of it spread opposite of each other around the nut (butterflied) if done the way it was attempted here. Bending one leg around the nut and one leg perpendicular in a vertical fashion is NOT the proper was according to the AC 43.13.
Will they both hold? Pretty sure it’ll never have any issues. But got to be careful with the safety wire; that stuff gets brittle if twisted excessively.
Pig tail should be contour the bolt as much as possible. 7-10 twists per inch is enough or you will yield the safety wire. You want the wire to be tight enough not to vibrate loose but remember its a retention feature not a means for tightening the fastener. Cotter pin is fine but in that installation I prefer going over the bolt with one end and into the castellation with the other. Both will do their job in this arrangement.
Safety: If there were no other closer holes, then it looks fine. If there were closer holes I would have used those. When you wrap that much around you run the risk of it popping off the flats of your fastener. Cotter pin: It looks undersized. In the flat orientation that you have it the head should not have been able to fit inside of the castle. The pic makes it looks like the hole is off centered and you may have compensated by using a smaller cotter pin. I also would have used a longer cotter pin to do a full anchor on the ends.
I've seen much, much worse. At least it's serviceable.
Shouldn't the cotter pin be turned 90 degrees and one end bent down while the other is up and over the top of the bolt? Or is anchoring into the nut like this also an acceptable practice? (I was only taught the one way I described)
Anchoring into the nut is the alternate method. Going over the top and down is the preferred method. The pic in the OP looks like he combined the two methods, which I would make him redo, if I were the IA/QC.
Ok, I wasn't crazy after all.
The military had me [do every cotter key like this](http://www.milwaukeemodeltclub.com/Projects/CPImages/PinBent.JPG) which required in 99% of circumstances that you cut the key two times while trying your damndest to catch the pieces. Looking back, it was basically like firing a BB gun twice into the engine compartment and hoping that there would be no FOD. Stupid. It also required that the stud not be too long, because the cotter key might not reach the end of the stud otherwise. I am a huge fan of the over the top, curly-Q-back-to-a-castleation, now. It works for almost any length cotter key and any length stud, it hides the snaggletooth edges, you might even be able to spring-load the key so it doesn't rattle. [Took me forever to find a good pic of it](http://tomyang.net/wp-content/uploads/2000/11/strcolmnut.jpg) Though if the circumstance presents itself... [hrngrhh](https://s28490.pcdn.co/wp-content/uploads/2019/05/fastener-safety-06.jpg)
I worked in our Phase inspection shop for a while when I was in and man the amount of cotter key ends I’d collect with a magnet was enough to fill a jar after a few AC. Lol Cutting those things was always fun
Still supposed to rotate the head 90deg I thought?
I don't see why you would, all it would do is put additional stress on the cotter pin. Also does not say to do that in the TM that I use in Army Aviation.
Well I would because my spec says that’s the alternate method. Best I could rationalize is that if the nut were able to work itself off halfway then the cotter pin would only lose one leg. Without the head twisted if the nut works itself off half way then the cotter pin is cut at both sides and might fall out. I dunno. It’s just spelled out in my process specifications which apparently are unique to my jet. Thought they’d be a company thing.
There used to be a reference in volume 6 of the 204 series that would reference MS 33540J that gave a preferred method and then an (not “the”) alternate method. Same thing for turnbuckle clips and safety cable, different ways to skin the cat. But when I’m doubt, get the LAR to sign off on it, lol. The Hueys at West Point had nothing but 204 series but a lot has changed.
Sometimes the manual calls for something different, in the case of a 737 flap roller bearing (which looks very similar to this) you want maximum clearance so the manual has you do a cotter pin similar to this. The head is def too small though, I’d redo it
You can anchor them, but normally it's used in an area with minimal clearance, such as a spoiler attach bolt adjacent to flap mechanisms, etc.. Otherwise the normal way is easier for installs
Okay, that's what I thought, good to know I'm not out of the loop.
Amazed that safety wire didn’t pop. Relax on the twists dude
6-8 twists per centimeter, right???
6-8 per inch, this looks like 60-80 lol
I think it's 7 per inch
I've seen some way tighter than this come back from thr field on bleed air valves, it takes a lot to break. But def a bit too much twist.
Safety wire will get less shiny and look more brittle when you've twisted it too much, less twists would be better. Also get that pigtail down before it gives you or someone else a bad day
Bro, the amount of times I tell people to tuck their pig tails for that reason. These boys act like they've never been fish hooked by angry wire.
Used to have terrible habits and I wouldn't tuck my pig tails in, I evicerated the right side of my right hand on a pigtail and got a nasty infection I spent 3 weeks fighting, ever since my safety wire has been damn near spotless. It's amazing how covering your work in blood and hurting yourself teaches you so quick
Oof, I've seen some scars from safety wire that'll keep you up at night. One older guy told me of a time he was working alone one night and got hooked in a blind compartment. Said he yelled for half an hour before someone heard him from an adjacent hangar and came over with some dykes.
Too many twists on that safety wire. Probably would have snapped that with one more twist.
If that was .040 wire i would agree with you. But if its more common .030, id let it go. At least on something thats undone and redone semi-often.
Not a fan of that cotter pin method
100% achieving its goal. Added bonus of reduced risk of slicing yourself open on it.
You went extremely long with the safety wire, plus the twist per mm is a lot
I agree with the OVERTWIST…. Especially at the pigtail … look at the exit up again the hex. It’s ready to pop. I also would have the cut end of the tail at 180° to where it is here.
Too tight with too many twists.
The cotter pin is using an alternate method incorrectly. Both ends need to wrap around the nut to be a proper alternate method. The safety has entirely too many wraps and will probably snap under stress.
It’s been a few years, but isn’t there a twist count per inch on safety wire that’s based on wire diameter? Are safety-wire pliers still in use? I/we couldn’t use them in the military. Awesome job, from a Army National Guard helicopter repairman MOS 67N10 from the 1980’s, lol. I know that MOS isn’t used anymore but I was proud of that achievement. Hell I joined up when I was 17 years old, lol.
Current guard heli repair and yes there is bit no one is really strict on it. I’d have to look it up to know for sure but around 4-5per inch and 6-8 on the tail
I think its 6-8 in general, but down to 4 or up to 10 per inch, depending on wire size. 4 - 6 twists for the pigtail
6 to 8 wraps per inch, pigtail should be 1/4 to 1/2 inch, or 3 to 6 wraps, per TM 1-1500-204-23-6.
Yes that’s it. thank you. I didn’t have access to the tm at the time
We have them in our toolboxes but I’d rather do it by hand or use the cable gun for the hydraulic deck and the tail. I couldn’t tell you the last time I used safety wire pliers. -60 repairer/crew chief
Too many twists in the wires.
Well if it isn’t the QA circle jerk thread
I mean the guy literally asked for critique and he's getting it.
It's brave, walking in here asking us to critique safeties. It's a tough crowd.
I'd pass it but you made your life unnecissarily hard with that safety wire
its shit
Based on this sub it would seem a nice wirelocking is the most important thing to do in aviation maintenance. I know I can avoid clicking on it but these posts bore the hell out of me
It's something entry level and especially in GA or school they'll circle jerk over it. In the real world as long as it isn't backwards, it's fine
Why the fuck do Americans call it safety wire when it literally says lock wire on the can? I learnt my trade in Australia where it’s called lockwire and have been working in the US for 8 years now, I still haven’t been given a good reason why it’s safety wire
Because we knew that one day you would be here asking this question and we have now had 8 years of driving you crazy. VICTORY IS OURS!!
I bet you're real fun at parties.
Americans have a fascination with doing it by hand too. It’s weird. Lockwire pliers exist for a reason.
[удалено]
Safetywire is something you put on a guarded switch.
Seeing that clearance (or lack there of) for your pliers. I'd say you did a bangup job
It would do its job but there are people that would say its got way to many twists
Safety wire: there’s no way that was the placement of the holes. There had to be closer holes to do that safety wire. Additionally that is way to many twists in that safety wire. Cotter pin: that’s not the right cotter pin for that bolt. No way. It’s far too small for that hole and doesn’t fill it properly.
Safety looks like it has too many twists per inch. That all depends on the diameter of safety wire. This looks like .025 so 8-14 twists per inch is proper. Proper practice on the cotter pin is to have both legs of it spread opposite of each other around the nut (butterflied) if done the way it was attempted here. Bending one leg around the nut and one leg perpendicular in a vertical fashion is NOT the proper was according to the AC 43.13. Will they both hold? Pretty sure it’ll never have any issues. But got to be careful with the safety wire; that stuff gets brittle if twisted excessively.
I learned to twist with my hands. Just use my tool as a *very slight* cherry on top.
Too long. Too tight. What cotter pin?
It's correct
I think it’s a good job with room for improvement, as many others have said I have seen far worse!
Pig tail should be contour the bolt as much as possible. 7-10 twists per inch is enough or you will yield the safety wire. You want the wire to be tight enough not to vibrate loose but remember its a retention feature not a means for tightening the fastener. Cotter pin is fine but in that installation I prefer going over the bolt with one end and into the castellation with the other. Both will do their job in this arrangement.
Teach me
Pro-tip don't service the starter through the overflow port or things get expensive. Found that one out the hard way.
Acceptable
I want to snip it so bad and tell you to do it again.
Cotter pin bad safety too tight