Square bolts

[Nolatoolguy]

I was wondering when did the stop using square bolts? Why did they stop using them? my guess is the hex has more points of contact an doesnt turn out as far on rotation but thats just a guess.

[anglesmith]

I was nearly going to say "they haven't stopped using them"!  But with a quick check I had to go back to the 1968 Blackwoods (our equiv.. of McMaster Carr) catalogue to find black square nuts offered.
The question to ask is when did they first started using hexagon ones? They couldn't come up with a definitive answer on Practical Machinist Recently! I'll let some one else answer the why.
Graeme

[Branson]

I was nearly going to say "they haven't stopped using them"!  But with a quick check I had to go back to the 1968 Blackwoods (our equiv.. of McMaster Carr) catalogue to find black square nuts offered.
The question to ask is when did they first started using hexagon ones? They couldn't come up with a definitive answer on Practical Machinist Recently! I'll let some one else answer the why.
Graeme

You can still get square nuts, and bolts.  I didn't do the ordering so I don't remember the company, but they have to be used for reenactments and living history and such like. 

Definitive when, probably not easy.  Guarantee the common use of hex in the 1860s as they were used in most, if not nearly all of the iron carriages for the really big cannons like the columbiads.  Seems there was documentation of hex in the 1700s.

[Ietech]

MSC carries them in a wide selection. There is also a lot of info when you google "Square Head Bolts"

http://www1.mscdirect.com/eCommerce/NavigationServlet/Fasteners-Adhesives/Bolts-Screws/Bolts/Bolts/_/N-77e3v?refinement=4289832817&searchandizedOk=Y

Fastenal also carries them.  Didn't check but I would think other major suppliers would still carry them.

[anglesmith]

I should have gone along with my first thought. The square bolt and nut is not obsolete yet! A google find plenty of makers and suppliers both here and in the US.  I was thinking nuts, as with the development of the steam engine and other machinery the need for closely space bolts and studs arose. this made makers use hex nut and make spanners-wrenches to work in more and more restricted places. Imagine trying to use square bolts and nuts on the modern car engine!!
Graeme

[rusty]

Ford , at least , still uses square nuts on body panels, by trapping one side of the nut with a tab, it can be kept from spinning when you put the bolt in the other side...

aside from fitting is a smaller space, hex heads and nuts are slightly stronger than square , the tips of the corners of a square nut are so far from the center that they contribute very little to the holding force on the bolt...(Because the steel is slightly elastic, they just bend upwards)
Having more tips, means you can make the metal between them thicker (further from the center of the bolt) and get a little more holding force from it, without making the overall diameter larger...

(dunno if that explains much, explaining geometry is kinda tricky ;P)

I somewhat suspect that the real factor that decided the final fate of square nuts was the detatchable socket tho, very hard to make a strong socket for square nuts, not so hard to make one for hex nuts, and sockets made it much much easier to put things together and take thenm apart..

[clovis]

I've been gathering square head bolts for a while now. Seems like I find a few here and there, and I hate to trash them knowing someone out there would like to have them for a restoration project.

[Branson]

I've been gathering square head bolts for a while now. Seems like I find a few here and there, and I hate to trash them knowing someone out there would like to have them for a restoration project.

Yeah, me too.  'Course,  I collect them because I *do* use them for restoration projects.

[leg17]

Square nuts would be easier to hand make by a blacksmith AND they have a more forgiving wrench fit allowance.
I surmise they began to wane along with the disappearance of the utilization of the local blacksmith.

[OilyRascal]

....... I *do* use them for restoration projects.

Let me know should you want a double handful sometime in a care package.  Despite hauling off nearly 8k pounds of nuts and bolts during cleanup, I still find them........found a coffee can full today.

[Branson]

I'd be mighty interested in a bunch of squares.  Maybe in a month I'll have my shop built and have a convenient place to hold them.  Right next to the 20 or so pounds of slot head screws I stumbled across -- flat heads, oval heads, and round heads!