Why the square head nuts and bolts?

[michaelod]

This may seem like a strange question, but my 1930 Model 68 is littered with square head nuts and bolts? There must have been some reason the car was manufactured with so many of these when hex head were available and found elsewhere on the car. These are something of a pain to work with as they are not compatible with modern sockets?

Anyone know why these were used so frequently?

Thanks,

[Ben Bruce aka First Born]

Michael, I am not able to answer your question, but there are 8 point sockets available that work on square heads.

Ben

[michaelod]

Ben,

Thanks for the tip on the 8-point sockets. These are hard to find. I found some Craftsman sockets sold individually at Sears, so I ordered 1 of each. Wish they had a full set available, but apparently these are not a real popular item anymore.

[Larry Schramm]

Were the square head bolts carry over from horse & buggy hardware and readily avaialble like the stove bolts on the older cars?

[Dwight Romberger]

Square head bolts were the fastest, least expensive bolts to make. The bolts were machined out of square stock. The shaft and threads were machined in one operation, leaving the square head.

[Guest WEB 38]

Thats why Buick furnished Vlchek open end wrenchs in the tool kit that came with the car, scokets whould have been to expenseve WEB 38 1920 K-45

[pepcak]

In 1930 I would expect to use square nuts and bolts in the wood structure only.....

[DavidAU]

Rolls Royce used square headed bolts on all the fixings on their engines, gearboxes, diff's etc which are aluminium up into the 50's because they provide more surface area under the bolt head and therefore spread the load better and they were able to position the head next to the flanges to stop the heads turning when the nut was tightened. They are still avalible today in most sizes in BSF thread but are very expensive.

David

[michaelod]

Dwight's description of manufacturing process sheds some light on the question. I thought there must be some reason why they would originally choose one type of bolt over the other and was curious whether it was an engineering or financial issue.

I find a lot of these bolts not only in the wood structure, but in the attachment of various body parts to the frame as well. I have been removing these up till now with open-end wrenches and if anything good can be said about them from the mechanics point of view, at least they are darn near impossible to round the heads off.

Edited February 5, 2010 by michaelod
text (see edit history)

[Dandy Dave]

Rolls Royce used square headed bolts on all the fixings on their engines, gearboxes, diff's etc which are aluminium up into the 50's because they provide more surface area under the bolt head and therefore spread the load better and they were able to position the head next to the flanges to stop the heads turning when the nut was tightened. They are still avalible today in most sizes in BSF thread but are very expensive.

David

Currious? Is BSF, British Standard Thread? And also, is that the same as Wentworth? I have a 1930 Rolls in my shed that is Wentworth. Dandy Dave!

[Bob Engle]

The first bolts and nuts were produced by blacksmiths hammering square stock which was a lot easier than forming hex stock. I am amazed on my 32 Buick by the wide variety of bolts, nuts and screws used throughout. The dash mount bolts are the most curious, truss head bolts with 1/4 by 24 threads per inch!! Of course the mounting nuts for many body parts attached to the frame are 1/4 inch bar stock. These don't need a wrench because the length of bar stock is long enough to jam against the frame.

Bob

[jscheib]

You have a 30 Rolls in your shed???

Strrange how we learn some things.

John

[DavidAU]

BSF thread is British Standard Fine. Whitworth is the British coarse thread. They are the English version of American UNF and UNC though they have different Thread per inch counts.

The only ones that are the same is that UNC and Whitworth are the same TPI up to half inch and then they change.

David

[Grandpa]

Hi Bob Engle,

A machine screw size which was uncommon, but still used in the 1930s is a number 14-24 size. A number 14 machine screw has a diameter of 0.242". This size appears in the SAE handbooks of the peroid. Since it is almost ¼", the size was dropped from most applications in favor of ¼-20 or ¼-28.

Grandpa

[Dandy Dave]

Back here in the USA, it is SAE, ( Society of Automotive Engineers) or Standard National Fine, also, Standard National Course. None of these will work on the Rolls that I have found. Neither will Metric. Also the wrench sizes are different than what we have in SAE sizes, or Metric over here. Whitworth is different than anything that I have found over here. I have had others tell me that the older Triumph Motor Cycles, and some other automotive stuff from GB is also "Whitworth" or, as you have said, BSF. If the thread pitch is different, and the wrenches do not fit correctly. Then it is not the same as we have here. Think I may dig a little deeper. Dandy Dave!

[Dandy Dave]

The First most obvious reason is that Whitworth has a pitch of 55 Degrees, verses our 60 Degree pitch. Although acording to this link, things are evolving and crossing over in some instances. Dandy Dave.

British Standard Whitworth - Wikipedia, the free encyclopedia