Mystery nut/socket combo

The nut is a plain old castellated nut. Nothing special. The socket/spanner is for a different type of nut, with wrenching features that are a series of square holes in a flush bolt or nut head. Sort of like a high torque flush fastener. The whole purpose is to keep the surface of the fastener flush, like the pin drive security fasteners in public places. I may be wrong, but I think I saw one of these a billion years ago and it seems like it would be for that funky bolt head...

Any castellated nut that I ever dealt with had flats to enable the use of a wrench - most often hex. Gerry :-)} London, Canada

I don't know off hand where to buy a socket for this nut, but unless I was going to be using it everyday, hare is what I would do. Measure the outside diameter of the nut and then find a 6 point socket with the same outside diameter. (Hey who says those made in China sockets are good for nothing?) Use an abrasive cutoff wheel to cut 6 wedge shapes out of the socket and carefully fit the remaining socket into the nut.

Cost in the 2 to 3 dollar range including the dozen or so dremel wheels you are going to go through.

Or you could spend a week tracking down a factory made one and spend 20 to

30 bucks.

This looks like a castellated bung for welding onto or affixing somehow to a larger assembly?

Peter

I typed in "spanner sockets" and hit search. Which returns lots of pictures of those two prong pin spanners, not something that would be the inverse of the nut pictured. I spent a good hour or so clicking on just about every link, and I think maybe one or two turned up something like the socket picture, but it was never a page that had a clear description and a proper name. Usually some crusty and esoteric page on an old server in the UK somewhere. I was hoping it'd turn up in a tool catalog online someplace, but no such luck.

I noticed that, which leads me to believe that the socket picture from the old Snap-On catalog is for a different type of nut with a similar design. Supposedly the nut in the photograph is slightly over a half inch in diameter, and is used to hold together a connecting rod in an engine.

While searching around a bit more later, I did have better luck searching for "castellated socket" and "castle socket." Those turned up something closer... mostly references to a tool used for suspension components on some motorcycles, but no pictures and no links to sources of the tool. Also it turned up links for tools to remove the knuckles from certain

4WD vehicles. Still no luck on finding the "actual" tool for the nut in question, though.

My old Land Rover used castellated nuts like these, and you would use a tool like the one shown to remove it. It does not seem to be exactly the same, but like your nut, the nuts used on my Land Rover had no flats which would have allowed me to use a normal wrench.

Just like the previous owner did. With a Pipe Wrench (Stilson to you lads downunder?)

Gunner

It's not unwise to remember that Mother Nature is essentially a murderous, sneakly, promiscuous bitch who has been trying to kill you since your conception.

Eventually she will succeed, perhaps with the help of your fellow man.

Life consists in putting off the inevitable as long as possible and taking what good and joy you can before her success.

Whether you attribute that situation to evolutionary forces, a fallen nature after Adam and Eve screwed the pooch, or whatever, it's no less true.

Be friendly, pleasant, unaggressive, and honest toward all and be prepared to ignore, avoid, or even kill anyone who is otherwise toward you. Being ready doesn't mean eager, just ready. What true friends are found in life will undestand and accept that fundamental rule of human interaction." John Husvar

Okay I had a brain fart. Not necessarily "plain old" but with an external spanner, even called a spanner in the USA, it can be tightened and removed. Sort of a semicircle with a square peg pointing in on one end and a handle coming off the other. Wraps around the nut. I do think there's a few in the Snap On catalog, IIRC. More often used on European stuff, I think.

| > The nut is a plain old castellated nut. Nothing special. | ........... | | Just how would you tighten it? | | | Tom

Maybe they were supposed to be finger-tight, held by a cotter pin , in which case the wrenches would work against the original intent of the nut design... ??

Ole-Hjalmar Kristensen wrote:

M> Maybe they were supposed to be finger-tight, held by a cotter pin M> , in which case the wrenches would work against the original M> intent of the nut design... ??

M> Ole-Hjalmar Kristensen wrote:

Yes, they are supposed to be locked by a cotter pin, but definitely not finger tight, as this is the nut that holds the wheel hub on the axle... The tool I used was a Land Rover special tool, documented in their repair manual. I think the design is to allow locking by the cotter pin in virtually any position.

faux-castellated nut

Well, you've had some interesting and valid answers, but I think your actual question has not been addressed.

The question you asked was concerned with the "trivia like this" and therefore asked for the "original and correct" information on this; not the "possibly how" or the "could be." (Not a criticism of the posters - this is the main topic of the group) Many here could turn, drill and thread a piece of hex stock and mill the slots for a replacement.

Now I don't know the correct "trivia" answer either ;-} but I think the answer about the "Land Rover" actually using them would give a valid place to start as that product evidently was a "factory design - used and installed."

Another comment mentioned "finger tight" which might also give an interesting aspect to the information. The "lugs" on the wrench look like they are, and should be, much shorter than the depth of the castellation; possibly to view when the cotter pin hole lines-up. This means that the torque-spec on the outward end might approach the "breaking point" of the extended parts on the nut.

I find this interesting and would appreciate it if, after researching and finding the answers, you would post the results here...

BTW - have you determined the thread pitch? A castellated nut usually has a finer thread than this appears to have, to allow "less travel" in tightening for cotter pin alignment.

Thanks, JHbs

BMW included a wrench like that in the tool kit on its old (R-50, R-60, etc.) motorcycles. IIRC it was used for removing the muffler.

--RC

"Sometimes history doesn't repeat itself. It just yells 'can't you remember anything I've told you?' and lets fly with a club. -- John W. Cambell Jr.

From what I've been finding, there's a lot of vehicles that use something similar on the ends of spindles and whatnot, and that many types of "spanner sockets" exist to work with them. Those sockets also show up in turbine repair, or so Google says. The thing is, those are generally significantly larger nuts than these. On the order of 1.5" or greater, whereas this one is supposedly just a bit over 0.5".

I'm definitely going with the "factory design" idea, it sure looks like something requiring one of those fancy overpriced dealer specific tools. It's supposed to be a nut holding a connecting rod together, so I'd imagine there's a special socket to allow for a good grip so that things can get torqued properly.

I'd be happy to do so... assuming I find some! I'd love to know exactly what it's called and what the history of the design is... chances are that's long lost at this point, though.

I'll tell you what I know. Supposedly it's off a 10mm connecting rod bolt, which doesn't clarify what the thread pitch is but it might give some clues. And the latest info about it is that the engine that used said nuts is a Maybach 1400cc V12. The castellations on it are, as it turns out, meant for a cotter pin as others have pointed out and there's an image of the nuts in an as-installed state. I've grabbed it and posted it here:

So it definitely looks like it'd require a socket on the end of an extension bar to reach the things, and that a normal castellated nut would have almost worked if the nuts weren't so close together. It almost seems like one of those cases where some engineers painted themselves into a corner with the design and had to "cut corners" (pun intended) on the nut to get it to work.

I'm thinking the suggestion of making a socket for it is pretty much the only solution for removing and installing the things correctly, since it might be that there is no official name for the tool or for that type of nut. I suppose we could christen it the "stripped at the factory castellated nut removal/installation tool!"

Interesting picture. What sort of engine, bike, car or aero? And only

1400cc? What vintage? '20s, 30's or later? I wouldn't think such a small engine would require the use of 4 nuts on the con rod cap, even if it was a high-revving engine.

I almost pegged the nut as some type of aero engine fastener, there's some peculiar types floating around out there for tight quarters like that. If I had to remove it, I'd make up a flat blade thin enough to fit the castellations, cut center clearance for the stud and find a sacrificial socket to weld it into. Hopefully, it isn't torqued to hundreds of ft-lbs.

Stan

OK you have a Mercedes specific nut so you need a Mercedes socket. Try calling (800) 741-5252 or check out

.

I have found that this is the cheapest place to get Mercedes parts, and if an aftermarket tool exists they will probably sell them.

Sadly, I've no more information available than what I've already given. Everything I know about it was gruuzed off another group, and no more information than what I've given here was given there. I'm assuming it's either car or bike, most likely car of some kind. And 1400cc with 12 cylinders sure does seem like it would have very tiny pistons on it, unless it had a tiny little stroke.

It's a con rod nut, so I'd guess it to have a spec of maybe what, 45 ft-lbs on average? I'm sure that varies wildly depending on a whole host of things, but from what I've experienced that seems to be reasonable for a ballpark figure. And those castellations look fairly wide, so you could probably get a pretty good purchase on it that way.

Chances are I'll never hear anything more about it than I already have, so my trivia lust may never be satisfied. Still, I hold out hope. The whole idea of using castellated nuts on connecting rods is turning up some new web search terms that might hold promise.

Well I don't know how you searched Google but there's plenty of mention and illustrations of spanner sockets.. As for the spanner sockets in question, they're still in my 90s Snap On cat. Look at the sizes involved and the drive size, they aren't for the average auto! :-)

Tom

...........

Just how would you tighten it?

Tom