Cotter pins which material is correct ?

[GophersGarage]

I have many cotter pin sets for wheel bearings and tie rods etc

but which ones are correct to use?

stainless vs steel vs aluminum. ???

I so far have been using basic steel ones

Your thoughts

 

[isb cornbinder]

I have never seen an aluminum cotter pin and very few cotter pins in stainless. I was a mechanic for a company that had 1365 mid-range vehicles. We always used coated steel cotter pins.

 

[The Cobbler]

I've never seen aluminum either. I would use the steel ones over stainless for any purpose where safety is a concern . stainless is weird material .

 

[M6erfan]

Unless it's a (very) specific application, zinc plated steel.

 

[ZRX61]

All the ones I use are either zinc coated (silver, cheap) or a Cad 2 (gold, not quite so cheap)

If you want to impress people, install them in accordance with Hawker Aircraft methods...

 

[ZRX61]

As an aircraft mech, half-assed cotterpin installation is one of my pet peeves....

 

[ZRX61]

The other correct way...

 

[GophersGarage]

I alway just use this way

light tap pin in then bend

 

[M6erfan]

The other correct way...

Yup

 

[GophersGarage]

I always used basic steel versions but you guys got me thinking about the gold cad ones I bet those are good for rust prevention

that’s kinda the point of this post .

 

[ZRX61]

I alway just use this way

light tap pin in then bend

And trim the legs

 

[GophersGarage]

Oh yes I usually pick the thickest cotter pin but they are always to long but no biggee easy to cut

 

[Lucid Moments]

As an aircraft mech, half-assed cotterpin installation is one of my pet peeves....

I will admit that I don't do cotter pins nearly as neatly as some of the other posts on here, but these two examples take the cake. First one is cotter pin instead of a bolt? WTF? Second one I am assuming that safety wire is supposed to be used there because I can't even figure out what those cotter pins are supposed to do.

 

[ZRX61]

I will admit that I don't do cotter pins nearly as neatly as some of the other posts on here, but these two examples take the cake. First one is cotter pin instead of a bolt? WTF? Second one I am assuming that safety wire is supposed to be used there because I can't even figure out what those cotter pins are supposed to do.

Apart from filling the hole in the bolt head they don't appear to be doing anything useful

 

[mikegt4]

Anti theft, now you can't get a wrench on the bolt head.

 

[matt_i]

The only ss version I have come across is on a Volvo Penta sterndrive's clutch-shift linkage. After ~20 years of constant water splash (its basically submerged when the drive is trimmed fully down) it looks pristine.

 

[ChevyEFI]

I always used basic steel versions but you guys got me thinking about the gold cad ones I bet those are good for rust prevention

that’s kinda the point of this post .

If everything is assembled correctly, the pin isn't going to typically get abraded or corroded away anywhere nearly as frequent as it's checked and inspected.
Good coated steel.

 

[Jarhead0408]

I always just use this way

light tap pin in then bend

That is beautiful. I'm going to do it that way from now on.

Question for those who use the CAD gold plated cotter pins; what's your preferred source for them?

 

[cvairwerks]

I typically buy mine in bulk from skygeek.com. You just need to know the correct MS part number.

At work, we’ve pretty much quit using safety wire and have gone to safety cable. A little more costly on the materials and tools, but way cheaper on labor. Even the least competent mechanics here can do cables in a single try.

 

[californiaHank]

I've never used anything but 18-8 stainless steel cotter pins on boat rigging, where there's lots of stainless hardware. But, I've seen lots of rusty cotter pins on car front ends, so I guess zinc-plated steel ones are pretty standard for automotive use. Plain (unplated) steel seems a really bad choice for anything that gets exposed to moisture on a regular basis.

 

[Mikeske]

I typically buy mine in bulk from skygeek.com. You just need to know the correct MS part number.

At work, we’ve pretty much quit using safety wire and have gone to safety cable. A little more costly on the materials and tools, but way cheaper on labor. Even the least competent mechanics here can do cables in a single try.

I was seeing that more as I got closer to retirement at Boeing but still actually preferred safety wire but I spent 40 some years as a aircraft mechanic using safety wire and was proficient at doing it. It did take some time to learn to get it tight enough and with the correct number of coils per inch. I never argued with the engineer if they speced the safety cable or safety wire as I could put either in. Just a personal preference was the safety wire for me.

Cotter pins preference was a coated mild steel pin and installed the way JSS showed was the normal for me.

 

[qqzj]

What is safety cable? Any pictures? Thanks!

 

[Neggy]

What is safety cable? Any pictures? Thanks!

 

[cvairwerks]

For those that are curious, NASM33540 Rev J, is the current spec for cotter key, safety wire and safety cable installation methods. As Rev J doesn't call out safety cable specifically, we have engineering directive to us, for direct substitution of cable for inconel wire in our work. Witness wire is still the same old .020" copper, from the 1930's.

 

[APEowner]

The other correct way...

I don't remember the number but this is the SAE standard.

 

[ez-duzit]

...stainless is weird material .

Come on! Stainless is used everywhere on boats.

 

[cvairwerks]

I don't remember the number but this is the SAE standard.

AS567K is the current SAE Aerospace revision.

 

[nh_yota]

I've encountered aluminum cotter pins before - just can't remember where. Most of the time I use regular old zinc plated steel pins from the drawer in the hardware store unless it's on a boat.

 

[gungatim]

LGR!

 

[PapasDaLife]

All the ones I use are either zinc coated (silver, cheap) or a Cad 2 (gold, not quite so cheap)

If you want to impress people, install them in accordance with Hawker Aircraft methods...

That is really something quite ****.

 

[ZRX61]

Every cotterpin you'll ever need...
Stainless & cad plated assortments:

Deluxe Cotter Pin Kit | Aircraft Spruce ®

Deluxe Cotter Pin Kit CAD-PLATED & STAINLESS 850 PIECE KITS

www.aircraftspruce.com

 

[ZRX61]

Bigger sizes:

Economy CAD Plated Cotter Pin Kit 500 | Aircraft Spruce ®

Economy CAD Plated Cotter Pin Kit 500 ECON COTTER PIN KIT 500

www.aircraftspruce.com

 

[jonesg]

The only ss version I have come across is on a Volvo Penta sterndrive's clutch-shift linkage. After ~20 years of constant water splash (its basically submerged when the drive is trimmed fully down) it looks pristine.

Its best to use all SS in a marine environment....and fully tinned wire.

 

[nbpt100]

I have never seen Aluminum cotter pins but I can only assume the rational is that they break if you try to reuse it. Steel ones get reused all of the time even though it is not recommended in shop manuals. I have seem people only bend one leg to make it easier to remove and reuse the next time. I am sure others have as well.

 

[anndel]

The other correct way...

That's how I always do mine and the ones I buy are all steel, not stainless or aluminum.

 

[bubinga]

I have many cotter pin sets for wheel bearings and tie rods etc

but which ones are correct to use?

stainless vs steel vs aluminum. ???

I so far have been using basic steel ones

Your thoughts

I've never really seen aluminum either I'd say the steel's fine stainless won't rust in there as much but they're usually not really an issue rusting.

 

[bubinga]

The other correct way...

That's the way I always did it.

 

[Sumboodie]

All the ones I use are either zinc coated (silver, cheap) or a Cad 2 (gold, not quite so cheap)

If you want to impress people, install them in accordance with Hawker Aircraft methods...

When I was in the Air Force, we had to cut one leg flush to the nut, the other bent over the top.

 

[bubinga]

I have never seen Aluminum cotter pins but I can only assume the rational is that they break if you try to reuse it. Steel ones get reused all of the time even though it is not recommended in shop manuals. I have seem people only bend one leg to make it easier to remove and reuse the next time. I am sure others have as well.

I have reused them a few times in a pinch when I didn't have a new one but I usually had a new one.

 

[ZRX61]

Now you've seen those pics I posted you will notice the half-assery when it comes to cotterpins while watching various shows on MotorTrend etc. Those so called experts at "The Guild" in Canada are always making an *** of it.