Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Cotter Pin question

Which is why split pins were (and mostly still are) made of mild steel. It takes quite some bending and straightening without breaking whereas most grades of stainless steel work harden and break much more easily.

As long as you don't buy from the likes of Halfords, a very cheap component.

Gentlemen thank you for your responses and as normal the topic has drifted a little. To refer back to my original post, I required information as to the size of the Cotter Pin I would require for retaining the castellated nut on the Stub Axle of my 4/4.
Thank you tmg513 I have taken your advice and ordered the required Cotter Pins in stainless steel from John Worrell
Martyn, I did not want to buy a boxed selection of Cotter Pins in stainless steel, which is a material I am endeavouring to use in regard to fastenings as much as I can, as the cost would not justify use of the 3 or 4 popular sizes and the remainder being left in the box on a shelf. I appreciate that the Cotter Pins in question will be in a relatively benign atmosphere; however I wish to maintain consistency in the build, so I will stick to my preference. I must question your concerns in the malleability of the stainless steel as the same grade of stainless steel is used in fixing wire a product that is required to be twisted and bent repeatedly in application.
Now I contest your comment about the term Cotter Pin which is a name I have used for this type of split pin all my life, and I am not from the colonies. The definition in the Collins English Dictionary is
A split pin secured, after passing through holes in the parts to be attached, by spreading the ends
A tapered pin threaded at the smaller end and secured by a nut after insertion
And in the Oxford Dictionary it is: A metal pin used to fasten two parts of a mechanism together.
Origin Mid 17th century: of unknown origin.
However I must admit its correct title is a Split Cotter Pin
Finally, Steve thank you for your kind offer of suitable Cotter Pins but I think I am now sorted. However I will try to make it to one of the Much Marcle Meets in the future, hopefully in a Morgan 4/4 complete with stainless steel Split Cotter Pins

The use and meaning of the term 'cotter pin' is obviously varied as the split pin meaning is either the first meaning or the second depending on which dictionary one uses. I did look the term up in a number of on-line sources and found views that either back up, or counter my point of view.

I don't doubt you can get stainless to a reasonable grade (but lots are not), and John Worrall is probably the best source for something like this where I'd not be too sure of many suppliers. However, the front wheel bearings on a Morgan are fully enclosed, the castellated nut and washer the pin fits into are a normal steel, and since the split pin is a single use device, rather pointless spending extra money on it as it's a hidden component, and won't ever go rusty.

Oh well, à chacun son goût.

I believe you can now get a very effective ointment for that..

What was size split pin did you eventually got from Mr. Worrell It would be handy to know for future reference.

My gosh. This sounds like EMOG. Mild steel split pin. One that fits the hole.

Button

I have used both terms but for different situations.
Split pin for the vast majority of uses,mainly car based.
Cotter pin when used to fix bicycle pedals to the hub...usually a solid tapered pin with a machined flat and bolt( but not always) to pull it tight.
I have a box for "bits and fasteners" and there is a range of sizes of split pins in there. So far never needed to go out and buy one to fit. Set it up years ago.

i am absolutely with sospan on this. I have always understood a cotter pin to be a solid tapered pin used to lock a radial member onto a rotating shaft so as to prevent relative movement betwixt shaft and member.

Split pins do a similar job, but are intended for retention rather than fixing - they are there to stop the member coming off (oo-er), but do not fix it in a mechanical sense, as the pin should never be tight in the hole.

A classic example is the bottom of the kingpin on a Midget where a cotter pin is used to lock the kingpin to the lower fulcrum pin. One of my early dismantling experiences. A tapered pin with a nut on the end.