Roger that, Steve!
Stainless cotter pins are ok, but be careful with stainless nuts and bolts. The tensile strength is often less than regular steel and they tend to gall unless you religiosly use anti-sieze.
Stainless or other wise what's the point of installing a cotter pins like that? Not only is it wrong but really what good is it doing? I hope your rods and mains are not like that. they will fail.
Some better ways
Thanks for the info Dan, all along I've always felt this is how the cotter should go in, but could never find any published info to verify. If this is in the "black book" I sure couldn't find it.
The sketch is from Dyke's Automobile Encyclopedia, published in the teens and twenties, a stable for the ordinary auto owner or the garage man too.
Ive always referred to that as "setting" the cotter pin. As its being set, bend the top over with a pair of needle nose pliers keeping it tight in the hole and trimmed after its peined into position, then trim the other side and pein it flat against the nut. Some guys would take a fingernail file and round off the cut ends, but I prefer to leave them sharp for the next guy... like a trimmed zip tie with a 45 degree cut a half inch long. Make sure they are all in line as the judges hate seeing mis-aligned fasteners.
Lets see... 10 minutes per pin makes about a 60 hour overhaul. I think the factory fastener guide calls out the correct length... ws
The right way in Dan's pic and Troop's explaination. Not only does it work well it looks good too.
I use nails or baling wire
Anyone who has taken apart and Original Model T will note...Ford assemblers inserted cotter pins and just bash them any which way.(Even in the motor) I use to take the time to split the pin, trim it if needed and hammer one tail over ,one down the side, Now I just bash the pin tails down the side and be done with. At least on the chassis stuff
I'm only fussy and take the extra effort with internal engine stuff. Never lost a battery box,front fender, bracket ,radiator or shackle doing it the Ford way...But I would never discourage anyone from doing a neat and professional job of cotter pining!
Most important and worth a mention is using the correct diameter pin..No small pins in a larger bolt holes!
Also note:A big NO_NO is never back up the nut to make the bolt hole line up and then insert the pin. .ALWAYS line up the holes when tightening!
If need be back up the nut and retighten to the next position that lines up. If you think it's to loose try another nut or file off a bit on the back of the nut if you have to.
I had one particular guy rebabbitt my 'T" mains . Great babbitt and machining job...After he showed me the bearings and the crank fit,he then over torqued the main bolts a bit during reassembly and then back down the nuts a good deal to line up the holes.
I instantly thought,"thank god I'm here to see it or I never would have check them"...I mentioned how that was a bad practice and he thought I was nuts.... I never had him do work for me again. He also thought real men don't where safety glasses when we swaped stories of getting metal shards in the eye removed. So that's where his head was at.
David, I'm not disagreeing with you; just looking for education --- What's wrong with backing the nut off to the next hole?
Of course I understand that might be bad practice on a bolt where torque is critical, like, say, a rod cap or main bearing cap, but why would it be bad on something not so critical, like a radiator mounting bolt or even a body mount bolt?
Maybe one of more technically enlightened friends will give you the science and theory behind it. I think it has to do with positive or negative torque and pressure on the threads. And negative pressure is not the way to go as it tends to loosen up from leaving pressure on the threads in the wrong direction. All I can say is that's what is taught since the begining of the mechanical age. It makes perfect since to me. I don't have a reason to study on much too any extreme. You can or not do it! Just like cotter pining,,the easy way I often do for not critical as you are saying stuff or use more standard practices on everything all the time. Maybe an experiment would be torque up some things..Pull up tight on some an not lock them..Then pull up tighter on others,then back them down and not lock them and see over time which loosen up first! if any Or all of them at once...Those pins aren't there just to cut knuckles LOL!
Its about he same thing as loosening a pipe fitting to have it line up. Take it off and begin from scratch. THEN STOP when its lined up... ws
How you bend the head and spread the prongs of the pin are less important than whether or not the pin really FILLS the hole in the bolt and the slots in the nuts. In 90% of the chassis' castle nuts, a 7/64" pin will fit snugly rather than the more loose fit of the standard 3/32". Once the larger pin is in place, it doesn't matter so much what you do with the head and the prongs. Anything that will keep the (tight) pin in place is fine.
On my own cars, I use 7/64" stainless pins and only slightly spread the prongs. Makes them much easier to remove and, in non-critical areas, they can be re-used.
Have used the recommended way to place cotter pins, and with the tangs close to the fastener, you won't get cut fingers either
As for the loosening up a castle nut to place the cotter, that is wrong, as you guarantee a weak fastener between the parts, oil leak, gasket shift and other issues. Take time to use the right fitting fastener, even if you have to work on either the castle nut, or the bolt or the part surfaces of what you are fastening.
From the US Military specs on cotter pins:
Ford Service photo, note the spring hanger castle nuts and how the cotter pins are fastened...
Good, bad, or otherwise, I have gone to using mostly safety wire with a twist instead of cotter pins. I have several sizes, types, seems to work well and is always the perfect length.
If you play guitar, you know about never backing off the string tension to tune. Always loosen up, then slowly tighten up to the tuning point.
Same as the nut torque idea above.
Notice from the photo, the shackle is installed correctly. When I assembled my '25, I used the Ford Service Book all the time for routing wires, and other things. Recently, I bought a bunch of original fasteners from Bob Bergstadt. In the box were some cotter pins, which I believe are genuine Ford. They are 3/32X 9/16, and look like they were probably raven finished.
I fully subscribe to the US military's comments. I haven't used cotter pins inside a engine in years (or in any critical application). I use "Loktite" and torque properly and have never had a problem. I have seen too many stretched rod bolts and I figure it comes from people trying to put cotter pins in and knowing they can't back off. Of course a stretched bolt is greatly weakened.
I do use cotter pins in spring shackles and and similar as you really don't need to torque them and they really show. On the drag link and some other spots I like Loktite for safety and cotter pins to avoid all the questioning by the other "experts" in the parking lot. Of course on the backend of the wishbone safety wire is the only answer.