What are the Nut Grooves on Door Hinge Bolt/Nuts for?

[kenscs]

Does anyone know the mechanical purpose (if there is one) for the grooves in the nuts on the Door Hinge Bolt/Nut/Lock Washer combo? I ran the Nuts and Bolts through a Vibrator Bowl last night to get all the surface rust and paint off of them, and when I removed them, they were so clean, I could now see what looks like a machined groove on only one side of the nut. The other side is beveled and smooth. See photos. I am assuming the did this so the split lock washer sits in the groove and has a better mechanical connection and does not slip around with the door opening and closing. That is pretty forward thinking and seems to me like it might have come on later models as an improvement to issues they saw with traditional flat nuts and repeated open and close cycles. I search the internet like crazy for stock listing of "Grooved Nut", etc, and no luck.

[o2batsea]

You sure they are OEM? the bolts should be "Atlas" What vintage are we talking? 50s, 60s 70s 80s?

[kenscs]

1971 Ex-MOD. I am pretty sure they are OEM since both sides (Passenger and Driver) match exactly. I could see one side having been replaced, but both match. The Bolt Head has the markings: B A at 12'oclock and an S at 6 o'clock. Obviously, S is the Tensile and Thread. Not sure if the B A mean Atlas. I found this link to British Bolt Head Markings. Still cannot find reference to Atlas Bolt head markings. This was a Continent-based unit and is LHD, so maybe some alternative manufactured parts from a Motor Pool in Belgium.

http://britishfasteners.com/index.php/head-markings

[mearstrae]

I've seen grooved nuts like that in applications other than cars, they were crimped in slightly to provide a lock to the nut, before elastic lock nuts were invented. Perhaps this is one of those? Chevy (and others) used a tri-crimp nut on their rocker arm studs to lock in the rocker arm settings.

'99 Disco II
'95 R.R.C. Lwb (Gone...)
'76 Series III Hybrid 109
'70 Rover 3500S

[cnfowler]

Wish I had an answer, but I don't. I've wondered the same thing. I've pull many nuts off the '69 of various sizes and uses and have seen that groove on many of them. I had never seen that before working on my Rover.


Colin

[o2batsea]

Since it's MOD there may be a possibility that they used a different standard for the fittings. However in that very turbulent time of British automotive history, the suppliers might have been a company that only lasted a few months. No telling.

[kenscs]

I did find a reference to BAX as a head bolt marking in a old Austin- Healey Restoration guide. Austin Healey 100, 100-6, 3000 Restoration Guide - Gary Anderson, p 184. "The following markings have been found on original [Bolt Heads]: Auto, Atlas, BAX, Bees, BL, ... RSB, Rubbery Owen, [etc]". So it seems like BAX must have been a supplier at one time to British Automotive Industry. I will keep trying to track down their history. kind of interesting to realize the rapid pace of creative destruction in British Auto industry at that time.

[Star27buck]

I found "NEWTON", "ATLAS" and "BAX" whilst taking the '53 S1 apart, all Whitworth or BSF.

[kenscs]

After doing a lot of research on this, I found a lot of interesting documents on the history of the British Auto Industry. As O2BatSea stated about turbulent time in the industry, it was a definite boom and bust time with thousands of companies going into and out of business. I am thinking of making the Fastener and Bolt Industry a small research project and create a reference chart or database of Bolt Manufacturers and Threads, Tensile Strength etc and then post here for others to reference for replacement help. I know starting this whole restoration project years ago, it was all new to me that there even was such a thing as BSF, BSW, BSB etc, so going the hardware store for replacement bolts was not an option. I might be able to shorten the learning curve for some (although that is half the fun!).

[Star27buck]

Try Metric and Multistandard Componants Corp, located at several locations in the US They have BSF, BSW, BA, BSPT and BSP...and tools.

http://www.metricmcc.com/catalog/catalog.aspx

[Les Parker]

BSF, BSW, BSB .....

First 2 I know , BSB ?? not sure about that.
BSP, where water flows.

[Star27buck]

British Standard Brass....there were dozens of others as well, restorers of British motorcycles have more troubles than we do...60 degrees, 55 degrees. Unfortunately, some are very close to US thread sizes and American brake light switches (1/8 27) into British connectors (1/8 28). It can be done, but only once.
Ask those who fuss with the early post-war MG's about fasteners with metric threads and Whitworth heads.

[kenscs]

Just bought a BSW and Metric screw pitch measuring tool. Should make life a little easier when identifying threads. My truck seems to be mixed metaphors. Head is Metric and almost every other part BSW.


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[Star27buck]

Perhaps they're Whitworth, which was the coarse thread in the UK. Metric wrenches fit some of the Whitworth fasteners. A set of proper Whitworth wrenches is a fine thing to have if you have a S1 or early S2....but costly....not that I need an excuse to acquire additional tools.

[kenscs]

....not that I need an excuse to acquire additional tools.

Ha, I know that life. "Honey, of course I need [fill in the tool name], or I will never be able to repair [fill in the hobby or project]. It absolutely cannot be done without a tool that take up at lease one more garage bay."

The metric thread was on my cylinder head heater take off. Someone had swapped it out for an Unleaded 8:1 head and must have pulled a metric one. The nipple that our hosts sell is a BSW. It was a pain to track it down. Turner Engineer was very helpful in debugging what was going on for me.

In the end, I should have just bought a new tool, a CNC Machine Lathe, and some 7/8" Hex Stock, and made my own. Talk about tool excuses...