finding a new cotter pin?

I managed to mangle the cotter pin that holds the coupling to the input shaft on my P6 power steering box, and now I'm having a difficult time finding a replacement. All I find online are split pins (USA call them cotter pins it seems) or cotter pins for bicycle pedal cranks. Does anyone know of a source for replacements?
Thanks in advance for any ideas! IMG_20201113_121618.jpg
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Hundreds of them on ebay
yup.....none of them the right size! mostly metric, some for vintage British motorcycles. eBay was the first place I looked. I was hoping to find a supplier of old machine parts, vintage engineering kind of thing. I will keep trawling eBay though.


Staff member
My mistake, I thought you were looking for a split pin. 'Cotter pin' seems to cover a few different items, including as you say, split pins, roll pins and even clevis pins.

Do you know what size you are after?

I can't see your attachment btw
Hi, I've tried to repair my post with the attached image, no idea why that disappeared!
The pin is 0.312" diameter and 0.9" long over the non-threaded part, 2.55" long overall. I thought it might be a standard part but even Machinery's Handbook is vague on these!


Active Member
Your pin looks to be mostly ok, is it just the threads which are 'mangled'?
In which case you should be able to chase the threads with a thread chaser.
They can be pricey but your local engineering shop maybe able to help; but usually they'll charge the price of buying the tool. :pbuy tools....

good luck.
What doesn't show in my pic is that the threaded part is bent backwards at the point where it joins the plain portion, I would worry that it is stressed there and might fail in service. It's probably not that bad really and I have some thread cutting dies so that might be worth a try.