Isn't this hardware unusual, on paper?

[jeejay]

7/16" hex nut diameter = 11/16" wrench size

7/16" hex bolt diameter = 5/8" wrench size

7/16" square nut diameter = 3/4" wrench size

7/16" square bolt diameter = 5/8" wrench size

That's according to Fastenal, where there are other instances of sizes not corresponding, either between nuts and bolts or wrenches, but only some of them list different sizes like that, while the majority are the same, regardless of being hex or square. I'm not talking about heavy or otherwise different parts (which may be expected to vary in outer diameter), and they don't seem to change based on thread type, so these inconsistencies are between standard parts, in 7/16" diameter for example.

Not that square fasteners are as typical, but they usually correspond to hex sizes all around, on paper (so to speak). I was wondering because some wrench sizes, like 5/8", 13/16", and 1" were only listed for square nuts. Or at least I know there's a hex pipe coupler that a 5/8" wrench fits too.

 

[Steiger9]

Yup, I've wondered that myself. The bolts/nuts we get from our local Ag stores all have corresponding head/nut sizes except the 7/16" bolts, which are as you described. I've never gotten a good answer as to why that particular bolt size is that way.

(The 1/2" plow bolts we get come with a 7/8" wrench size nut instead of the usual 3/4", but that's a specialty situation I'm sure.)

 

[jeejay]

So yours was unusual in practice (thanks, I don't have an assortment to compare). They also say a 9/16" hex bolt = 13/16" wrench size, while a 9/16" hex nut = 7/8" wrench. Other differences were to do with the square fasteners.

all have corresponding head/nut sizes except the 7/16" bolts

So your 9/16" hex nuts and bolts are the same wrench size?

 

[Steiger9]

9/16" bolts are a less common size anyway.

 

[jeejay]

Another oddity are their "High Nuts". High nuts have a taller profile than a standard hex nut, they say. However, I don't know what they mean by profile, because they list the same wrench sizes as those listed for standard hex nuts with the same bolt diameters.

Actually, it looks like they are a wider profile, and that's just an odd way of putting it (to me), to say they are taller or "high" like that. Because, by convention, wider coupling nuts are not called skyscraper nuts. Maybe they are considered to be very tall though, and not wide, like the jaws of a wrench may be referred to by width for adjustability (but I think of a wider wrench fitting a taller nut, because they otherwise refer to "short" nuts as being thin, and those require thin wrenches, not stubby or short ones).

Well, jam nuts are said to be low profile, typically half as tall as a standard nut. Fine, but thin wrenches fit them, so it's kind of like calling a thin person shorter than average, based on their profile as such. Nope, thin wrenches fit short nuts, duh! Well, saying that a low profile wrench fits a low profile fastener would make more sense all around. Describing those as "higher profile nuts" would be better than "taller profile" I'd say, because it refers to depth, not height. As with the thread protrusion of a bolt, it involves the depth that a nut is threaded onto it, and a lower profile nut would allow for higher (or increased) depth when threading it on, where a "deep" socket may be required to access it (or they should call that a tall socket, and it's low profile counterpart a short socket, but they don't). Deep sockets refer to a "high profile" then, and low profile sockets refer to "shallowness", NOT shortness. The same goes for "thin" wrenches, except they should just be called low profile, or shallow also. The rest are standard profile, or standard depth.

I guess the wider profile fasteners (in effect) are what they call "heavy", where wrenches with wider jaw openings may be necessary to fit around those with the same inner diameter as standard weight fasteners. It's no wonder they call people nut jobs for losing their minds. I was just thinking of the hardware in terms of wrenches, not sockets, to make sense of its misnomers (but then I was comparing more than one misnomer, including the tools). Not to say that "high nut" is a misnomer in itself, but them saying that high means it has a taller profile defines it as one (unlike simply saying it has a higher profile, or elaborating that such a profile refers to depth in terms of fastening).

 

[Farmall 1066]

7/16" and 9/16" hardware isn't uncommon if you work on Massey Ferguson or Oliver tractors.
Working on old stuff, especially, you find all sorts of deviation from today's standards.

 

[jeejay]

Have you found that either of those bolts have a different hex size than the nuts, or are tractors one sided that way?

 

[sberry]

7/16 is an ag size. One set of wrenches can work on 1 nut and bolt combination and the over sized nut was good on shovels and tines.

 

[jeejay]

So the over sized one would be what? Larger than 5/8". Commonly 11/16" then.

And ag refers to agriglyphs? I don't know, looking at hardware is like investigating crop circles.

 

[DFB]

So yours was unusual in practice (thanks, I don't have an assortment to compare). They also say a 9/16" hex bolt = 13/16" wrench size, while a 9/16" hex nut = 7/8" wrench.

I can vouch for that! I changed almost 100 9/16" nut and bolt combos on a 3PT rototiller at work to R&R the C tines. Working my way across from left to right I had to keep reversing my sockets and wrenches...what a PITA that was.

 

[cliftonbros89]

I've ran across this on several older Deere's as well. Tractors and some equipment. I don't know any reason behind it. I've just come to expect it after awhile.


Sent from my iPhone using Tapatalk

 

[jeejay]

Thanks for the points of reference, they seem to be missing from most descriptions, but a least those aren't all typos.

 

[Moparman390]

I'm just guessing here but the slightly larger nut on the square size is to give it a little more strength and rigidity as the hex nut probably has a little more material and that material is distributed more evenly around the circumference of the bolt.

 

[jeejay]

They say that square nuts have a large surface area, which resists tightening and loosening, and the head design of square head bolts enables an easier wrench grip for nut tightening.

A few of the square nuts list a 1/16" larger wrench size than their hex counterparts, and the rest list the same wrench size. Two of the square bolts list a 1/16" smaller wrench size than thier hex nut counterparts (which are typically the same as hex bolts, except those already mentioned). For example, the 1/4" square bolt has a 3/8" wrench size vs 7/16" wrench for a 1/4" hex bolt, while the 1/4" square nut lists the same size wrench as the hex nut (7/16").

 

[sberry]

It works on over size holes better too.
Ag refers to agricultural,, lots of the older equipment used 7/16. A lot of it. Some found on older tractors but implements used it. Not only on structural but plow shares and cultivator shovels.
Back in the day many wrench sets were in rolls, you could open the roll and use a single wrench set without the need for duplicates.

 

[jeejay]

Thanks for the info. So it's weird that a 1/4" square bolt would be under sized compared to a square nut, or hex nut and bolt, given that those aren't over sized.

 

[alex71]

Both nuts and bolts come in standard (light) hex and heavy hex. Some nuts also come in a thin hex. For example, 7/16 nuts come in 5/8 AF (thin/light hex), 11/16 AF (Standard light hex or Finished), and 3/4 AF (Heavy hex)

 

[jeejay]

That's interesting, although they have the heavy ones separated by category, and it appears that the specification reference number corresponds to the category. I was looking at standard ones, which show the same specification between hex and square, which is different than the heavy versions (of hex), and none seem to specify being thin, or have any different information other than wrench size (I didn't study every detail, but don't see anything obvious besides that, which the agricultural variations would explain somewhat). Whether they are arbitrarily thin or not based on the wrench size alone, there could be more info listed... I was casually going over those, and don't have any books on the topic (except maybe that's the minimum minimorum necessary to even look at hardware, on paper). Just say minimum minimorum five times fast...

 

[larry_g]

That's interesting, although they have the heavy ones separated by category, and it appears that the specification reference number corresponds to the category. I was looking at standard ones, which show the same specification between hex and square, which is different than the heavy versions (of hex), and none seem to specify being thin, or have any different information other than wrench size (I didn't study every detail, but don't see anything obvious besides that, which the agricultural variations would explain somewhat). Whether they are arbitrarily thin or not based on the wrench size alone, there could be more info listed... I was casually going over those, and don't have any books on the topic (except maybe that's the minimum minimorum necessary to even look at hardware, on paper). Just say minimum minimorum five times fast...

Get your hands on a Machinery's Handbook and it will give you details on the sizes of a lot of fasteners. If you can get one from the '50s to campare with today's selections.

lg
no neat sig line

 

[Lelandwelds]

I used to wonder about things like this but I tired of the strange looks.

I suspect it is just inertia or tradition or "best practice". Why is blue PEX cold water but blue wavelength is hotter than red? Why are right hand threads standard? Why is the worldnot metric? Why is barb wire still sold by the rod? Why do phones and calculators not use thesame layout?

I bet the first guy to mfg the first one had that steel on hand for some other purpose. As a corollary, invent something new. You can make an obvious decision that people will ponder for eternity.

 

[leg17]

So.....what's the question again?

 

[ttpete]

Years ago, the USS coarse thread fasteners used bigger hex sizes than the SAE fine thread fasteners. USS flat washers have a larger OD than SAE ones.

The Society of Automotive Engineers (SAE) standardized the fine thread series of fasteners about 100 years ago for automotive use and it was then accepted by industry in general.