What is it? CI

Castellated:

Nope, I looked it up, just for you.

Just because you don't want to be technically correct to know there is a difference, doesn't mean you have to accuse everyone of "dumbing down." The problem is that you call castellated nuts slotted nuts when they are not. Castellated nuts and slotted nuts are two different nuts. I know what a catellated nut is and what a slotted nut is. I don't make the mistake, as you do, of mixing the two. Hmm, maybe you are too tired to look that up. In your world, a cap screw is a cap screw. So go stock your shelves with metric bolts and spend your life trying to fit them in US standard threaded holes while telling yourself the whole time that there is no difference.

Then , I guess this really shows how clueless you are.

Yup, definite cluelessness. Who says it isn't current practice?? Just because you say?? It would seem that you are one of the masses that only your experience is to be quoted!

Nope.

Yup.

That must be the American OED. My Compact OED doesn't have that, and only references very general castle-like or castle-strewn thingies.

er

SPS technologies sells slotted and castellated nuts:

Safety wire is often used with the castle nuts. Martin Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net NRA LOH & Endowment Member NRA Second Amendment Task Force Charter Founder

Enoch Root wrote:

Those are self locking nuts not designed to be used with a split pin so a different type of beast altogether. It makes a certain point though. There are many types of nut with slots in them including ones with horizontal slots which almost slice the nut into two halves (another type of self locking nut). The term "slotted nut" is therefore almost meaningless without further specifying what sort of slot. However everyone knows roughly what a castellated nut is even if there is a miniscule distinction between nuts with a round bit above the hex and those without.

Quite why Mr Smith is so worked up about this distinction I have no idea and his assertion that 'true' (by his own definition) castellated nuts (round bit above the hex) are not used on vehicle axles when they clearly are was just flat wrong.

My only remaining interest in this mainly pointless and pedantic bickering is a vestigial curiosity about the reason for some nuts designed to be used with split pins having a round bit above the hex and some not having that. As for terminology I'll continue to call any nut designed to be used with a split pin a castellated nut whether it has a round bit on it or not. At least that way everyone even vaguely associated with engineering or mechanics will know what the hell I'm talking about.

-- Dave Baker

According to Dave Baker :

My own opinion about this is that the ones with the section turned round lets you bend the cotter key legs to wrap around that section, and keep the entire cotter key within the profile of the hex diagonal, so a rotating cover (grease cap, for example) will not drag on the cotter key. When dealing with a nut which is just slotted for the key, without the turned section, one leg is bent down along the flat of the nut, and the other is bent up and over the end of the threaded stud, which increases the chances of it dragging on the grease cap.

Agreed. IIRC, the official shop manual for my MGA used that term.

Enjoy, DoN.

No I don't, slotted nuts are castellated..

Looked it up? Yeah right. Have another look.

Tom

Restaurants call them "Rocky Mountain oysters." If the menu said "castellated nuts", some customers would keep their mouth shut.

No, that's the full OED. I work at a Canadian University that has the whole thing online and fully-searchable.

Yeah? Mine...'s got a little magnifying glass! ;-)

er

Well, sure, if you only look at a definition written in 1889, you won't find a usage where the earliest cite is 1904, will you? Go to Volume 2, page 3913, and you'll see the definition from the 1933 Supplement.

Guess it didn't help, eh? :-)

I'll be darned. Never looked at the supplement. I've only had it since January.

er

Oh! I get it! The "slotted" nuts are "self-locking" - the slotted part is necked down, holding the nut on the stud or bolt by brute-force friction. You thread it on, and when the slotted part gets to the bolt threads, it becomes very hard to turn, and conversely, it's very hard to loosen it; they might even be for "permanent" installations.

Thanks! Rich