6 pt or 12 pt - help educate me!

[chaser]

Okay, this may be a really fundamental question, but I'll ask anyway.

What are the pros/cons of 6 pt vs 12 pt sockets and wrenches? Does it matter? Do one set have advantages over another?

Thanks!

 

[KX250Fmotoracer]

6 pt
PROS
Much higher torque capacity
Works on slightly rounded fasteners
Cheaper

Cons
Less versatile (in RARE applications when using a breaker bar in a confined area, or a low tooth count ratchet)

12pt
Pros
More uses in tight areas (rarely...)
Can be used on 12pt fasteners (ARP engine bolts, head bolts, etc)

Cons
MUCH more likely to round the hex, especially on smaller fasteners (very commonly seen on 13mm drain plugs)

If you're buying your first few sets of sockets, go for the 6 point. You'll avoid rounding bolts, and are more likely able to remove bolts that someone else rounded! (doh!)

 

[iroc409]

I thought in that socket comparison thread someone did, the wear marks on the nuts from 12 and 6-pt fasteners looked pretty much the same. Am I thinking incorrectly?

I prefer 6-pt when usable, but most of my 1/2" drive stuff has been 12-pt. That's either what came in the set, or what I could get a deal on.

 

[SINISTER]

Right and wrong ^

12pt have a much higher torque capacity due to more surface area when used with 12pt bolt heads. Only common to round out as you said HEX heads not 12pt bolt heads.

6pt have a higher surface area when used with 6pt bolt heads.

They are both used in their specific applications, to be specialized you want both sets. If you do general work 6pt sets are fine as you rarely see any 12pt bolts.

One more PRO to 12pt is that if you work in a shop and a car comes in with wheel locks and you don't have the wheel lock key. If you own a few different size 12" sockets, if you have the right size it can be hammered over the lug nut and taken off.

 

[Buckgnarly]

Buy both!!

 

[GirlnAgarage]

I thought in that socket comparison thread someone did, the wear marks on the nuts from 12 and 6-pt fasteners looked pretty much the same. Am I thinking incorrectly?

That's what I thought too.

If the contact patch is the same on a hex head bolt with a 6pt pr 12pt socket why is the 12pt more likely to round the nut?

Is it because the 6pt socket flats match up to the bolt head and therefor there's no room for the socket to jump over the flat edge? Unlike the 12pt?


I have both types and use both types.

 

[volunteers]

My question is: same brand 6pt and 12pt socket, usually which one is more expensive? or about even?

 

[oldtools]

That's what I thought too.

If the contact patch is the same on a hex head bolt with a 6pt pr 12pt socket why is the 12pt more likely to round the nut?

Is it because the 6pt socket flats match up to the bolt head and therefor there's no room for the socket to jump over the flat edge? Unlike the 12pt?


I have both types and use both types.

12pt has less contact area than 6pt (the area in which the socket contact the bolt), so it will round off the bolt much easier than 6 pt.

 

[GirlnAgarage]

12pt has less contact area than 6pt (the area in which the socket contact the bolt), so it will round off the bolt much easier than 6 pt.

I looked at this 13mm socket comparison: http://www.garagejournal.com/forum/showthread.php?t=73245

The contact patches don't look distinctly different in their size. What does stick out is the placement of the contact.

With the above documented comparison noting contact patch locations on the hex nut face, my question still stands. Why is the 12pt socket still considered more likely to round a nut compared to the 6pt socket?

 

[wreckerman5357]

I disagree on 6 point being better on slightly rounded fasteners. Many times have I had a 6 point not fit onto to a rounded fastener but was able to fit a 12 point on (sometimes with persuasion from a hammer) and remove the fastener. That said, I use 6 point sockets most of the time as they are less likely to round in the first place.

 

[oldtools]

I looked at this 13mm socket comparison: http://www.garagejournal.com/forum/showthread.php?t=73245

The contact patches don't look distinctly different in their size. What does stick out is the placement of the contact.

With the above documented comparison noting contact patch locations on the hex nut face, my question still stands. Why is the 12pt socket still considered more likely to round a nut compared to the 6pt socket?

The link only show when the socket first contact the bolt without much loading. As the load increase, the bolt goes into elastic deformation at the contact area. For 12pt, the contact (or bearing) area (and the shear area across hex edge) do not change much as the bolt deform elastically. For 6pt, the contact (or bearing) area (and the shear area across hex edge) increase as the bolt deform elastically; therefore, less stress on the bolt head.

 

[iroc409]

Is there really that much deformation in something torqued generally at less than 100 ft-lbs? The explanation sounds reasonable, but I would think it would be more of an issue with an impact tool than a plain chrome socket (that isn't being used on a 6-ft breaker bar).

We've discussed it some before, but usually the overly large fasteners, in the 3/4" drive range, are generally 12-point sockets with apparently no issue. Those are likely to have far more torque applied, why would they generally choose 12-point for that application if there is that much issue with elasticity?

I didn't read the whole other thread again, but:

Each test nut was torqued three times with the socket in a different orientation each time. This was done to give an average pattern from each socket. The test nut was then removed by loosening the nut below the washer to avoid any more imprints on the test nuts.

It doesn't say what spec they were torqued to, but if they were torqued down to a reasonable amount, wouldn't the deformation be indicated in the markings? The socket and nut would be made of different material, and flex differently.

I don't know much about materials yet to probably have much of an in-depth technical discussion (though it's something I will need to be familiar with in the future). I'm just curious.

 

[GirlnAgarage]

From Post #2

Here are the pictures of the socket's imprints on the nuts. These nuts are Class 8 and from McMaster-Carr. The part number is 90591A161. Dykem layout fluid was used. Each test nut was torqued to 27 ft-lbs using a Harbor Freight torque wrench which is the standrd dry torque of M8 bolts. The test apparatus is a bolt with several nuts on it, a washer, and the test nut. The test apparatus was held by my lovely assistant seen here.

(snip)

Each test nut was torqued three times with the socket in a different orientation each time. This was done to give an average pattern from each socket. The test nut was then removed by loosening the nut below the washer to avoid any more imprints on the test nuts.

So, for purposes, the test was conducted to discover contact point location and size.

 

[bimmerZ5]

if I had to choose between 6pt vs 12pt, i would pick the 6pt first and get the 12pt later when extra funds are available. i mostly work on cars, and I rarely encountered 12pt hex fasteners. depends on what you're doing...

as for getting into tight spaces, you're better just getting a fine tooth ratchet to allow you to adjust the orientation of the socket until it fits over the fastener than to depend on a 12pt fitting at a convenient angle. The 12pt socket gives you 30 degrees between orientations, while a fine tooth ratchet can adjust 5 degrees or less. the only situation where this might not work, is if you're using a breaker bar that doesn't ratchet, but in that case the 12pt isn't guaranteed to give you a good fit.

 

[GirlnAgarage]

I've run into the not enough room with a breaker bar using a 6pt socket. It was changing shocks on the truck that had to stay on the ground. Took for freakin' ever for 100ft/lbs.

 

[GirlnAgarage]

The link only show when the socket first contact the bolt without much loading. As the load increase, the bolt goes into elastic deformation at the contact area. For 12pt, the contact (or bearing) area (and the shear area across hex edge) do not change much as the bolt deform elastically. For 6pt, the contact (or bearing) area (and the shear area across hex edge) increase as the bolt deform elastically; therefore, less stress on the bolt head.

I see. Thanks.

 

[Super Sport]

As a hobby mechanic I encounter having to use a breaker bar far more than I have encountered a problem with rounding a nut. Therefore, in my own opinion, I definitely recommend 12 pt over 6 pt.

 

[oldtools]

Is there really that much deformation in something torqued generally at less than 100 ft-lbs? The explanation sounds reasonable, but I would think it would be more of an issue with an impact tool than a plain chrome socket (that isn't being used on a 6-ft breaker bar).

We've discussed it some before, but usually the overly large fasteners, in the 3/4" drive range, are generally 12-point sockets with apparently no issue. Those are likely to have far more torque applied, why would they generally choose 12-point for that application if there is that much issue with elasticity?

I didn't read the whole other thread again, but:


It doesn't say what spec they were torqued to, but if they were torqued down to a reasonable amount, wouldn't the deformation be indicated in the markings? The socket and nut would be made of different material, and flex differently.

I don't know much about materials yet to probably have much of an in-depth technical discussion (though it's something I will need to be familiar with in the future). I'm just curious.

It all depend on the contact and shear area. If it is small enough, 100 ft-lbf will shear the hex edge off. The specified apply torque is not enough to round the hex head even with 12pt. The hex edge at the contact area will elastically deform, but not plastically deform. There is a big difference between elastic and plastic deformation. Rounding of bolt head usually happen during un-torquing. The torque to remove is sometime much much higher than the torque to install due to rust, dirt, corrosion, etc.... The torque can be high enough to cause plastic deformation by using 12pt socket. With 6pt, even with the high torque, the stress is reduced significantly so plastic deformation (rounding off) is less likely.

 

[Even Steven]

If you're trying to loosen a stubborn hex-shaped nut or bolt head, you're always better off using a 6-point socket or wrench. A 12-point will definitely be much more likely to round off the fastener because it puts more stress on the "points" and less on the flats.

I only use my 12-point tools for 12-point fasteners. My 6-point tools are used for 6-point fasteners.

If you have neither and want to know which to buy first, that depends on your situation. It is true that 12-point tools are more adaptable because they'll work with 6- or 12-point fasteners, but most people don't encounter 12-point fasteners very often. So I'd say most people are better off if they buy the 6-point stuff first because they are much more likely to encounter 6-point fasteners and they'll be less likely to damage them with 6-point tools.

 

[GirlnAgarage]

Hmm Would be great to see a side by side test like the other one, just to see it in action.

Not that I don't believe the 'book reading' but it is always neat to watch the experiment If one were to put together the experiment, what hardware, sockets and specs would be considered a standard?

 

[thesilverone]

how about 24 or 48 point sockets?

 

[ajchien]

As a hobby mechanic I encounter having to use a breaker bar far more than I have encountered a problem with rounding a nut. Therefore, in my own opinion, I definitely recommend 12 pt over 6 pt.

Have you considered turning the 6 point socket? See link below

http://www.garagejournal.com/forum/showthread.php?t=88377

 

[Outlawmws]

Personally I have never rounded a nut or bolt off just by using a 12 pt socket with one exception: A small completely worn out (ground down) 5/16 Armstrong socket in 1/4 drive. The machine screw nuts in 5/16 are very soft and this socket is toast to begin with....

Mind you, I'm not in the rust belt, and if I do have a stuck on rusted nut, I'm more likely to use a nut splitter on it than mess around trying to "work"it off, or, I'll use heat/penatrant on it. (Spent most of a night getting/splitting all the nuts off my old '47 Ford PU under the chassis during it's initial tear down back in the 70's)

Most of my std length chrome 1/2 and 3/8 drive sockets are 12 pt.

 

[iroc409]

It all depend on the contact and shear area. If it is small enough, 100 ft-lbf will shear the hex edge off. The specified apply torque is not enough to round the hex head even with 12pt. The hex edge at the contact area will elastically deform, but not plastically deform. There is a big difference between elastic and plastic deformation. Rounding of bolt head usually happen during un-torquing. The torque to remove is sometime much much higher than the torque to install due to rust, dirt, corrosion, etc.... The torque can be high enough to cause plastic deformation by using 12pt socket. With 6pt, even with the high torque, the stress is reduced significantly so plastic deformation (rounding off) is less likely.

That all makes sense, but I'd still say it has to be compared to the case. How much more torque is required to remove a fastener, say my truck's lug nuts secured with 85 ft-lbs? At what torque will the fastener fail and sheer? I guess what I'm getting at, is it a case of diminishing returns? If the likely much higher-torqued 3/4" drive items aren't using 6-point, does it really matter that lower drives aren't?

I was just in one of the shops at work this morning, noticing their (I believe) Snap-On 12pt impact sockets (1/2" drive). It's been done, though I'd certainly prefer (and use) 6-pt impact sockets.

I'm just a DIYer, but I don't think I've ever destroyed a fastener while *properly using* a quality tool. I've certainly done it with improper tools.

I totally agree that the 6-pt socket would be less likely to sheer the fastener in the situation you describe, I'm just curious in reality what that would take.

 

[tyndall]

A 12-point will definitely be much more likely to round off the fastener because it puts more stress on the "points" and less on the flats.

Nope.

Each nut was removed with a different socket or wrench. Which do you think were removed with a 6pt and which with a 12pt?

We can go with theory, and use the elastic vs. plastic deformation, or use real world results. The real world says 6 or 12 doesn't matter, unless the nut is worn, already rounded, or weakened. If the nut is in good condition but seized, either will transmit enough torque to either break it free or shear the bolt.

Keep this in mind. Whenever the 6 vs 12 argument is made, the majority says 6 point is better, except when you need more positions like with a breaker bar. Isn't it odd that they endorse using an "inferior" socket with the handle that is going to give you the most torque?

That said, I never use 6pt unless I encounter a fastener that someone else has severely damaged. Maybe a couple of times a year.

 

[ajchien]

Nope.

Each nut was removed with a different socket or wrench. Which do you think were removed with a 6pt and which with 12

I have no idea, but I wanna play for fun. 6,12,6,6,12,12. How'd I do? (PM would be cool, Then others could still make guesses)


As for rounding fasteners, I have no facts or theories. I simply have notice that the only times I round off bolts are when I use a cheap 12 point socket combined with having an adventure where my ratchet and socket go flying.

 

[KX250Fmotoracer]

One more PRO to 12pt is that if you work in a shop and a car comes in with wheel locks and you don't have the wheel lock key. If you own a few different size 12" sockets, if you have the right size it can be hammered over the lug nut and taken off.

I've never seen that done. Good to know

 

[BigAl62]

Buy both!!

I agree! You can't have too many tools!!!!

 

[iroc409]

As for rounding fasteners, I have no facts or theories. I simply have notice that the only times I round off bolts are when I use a cheap 12 point socket combined with having an adventure where my ratchet and socket go flying.

What about an expensive 12-pt socket?

 

[Even Steven]

Nope.

Each nut was removed with a different socket or wrench. Which do you think were removed with a 6pt and which with a 12pt?

We can go with theory, and use the elastic vs. plastic deformation, or use real world results. The real world says 6 or 12 doesn't matter, unless the nut is worn, already rounded, or weakened. If the nut is in good condition but seized, either will transmit enough torque to either break it free or shear the bolt.

Keep this in mind. Whenever the 6 vs 12 argument is made, the majority says 6 point is better, except when you need more positions like with a breaker bar. Isn't it odd that they endorse using an "inferior" socket with the handle that is going to give you the most torque?

That said, I never use 6pt unless I encounter a fastener that someone else has severely damaged. Maybe a couple of times a year.

Your picture is pointless because it is possible to round off a fastener with either type of socket/wrench. What I said was 100% factual and true. Maybe you missed the part where I said "more likely".

Any mechanic worth anything understands that a 6-point tool is designed for a 6-point fastener. There's really nothing else for me to say if you don't at least understand that basic fact.

BTW, educate yourself on AS-954 before you bother replying.

 

[Old Donn]

Buy both!!

What Buck said.

 

[Spam16v]

I have 6 point SO sockets for primary use, I have a few sets of other brands in 12pt if I need them. 88tooth ratchets help make them easier to use in tight quarters, and they last longer.

 

[wornoutoldman]

If you can only afford one set (space or cash restrictions) go with 12 point. Otherwise get both. Rule number one of the TWC (tool ***** club) says you never have enough tools.

 

[cotjocky]

My first little tool set was a craftsman set that had all 12pt sockets. I had a rusty 1974 Beetle. It was a nightmare to say the least. I was constantly rounding bolts. That turned me off 12pt and I only use 12pt when it is a 12pt bolt. 6pt all the way for me when it comes for sockets. I keep 6pt wrenches and 6pt ratchet wrenches for the really stuck or rusty stuff.

 

[ajchien]

What about an expensive 12-pt socket?

Yup, I did specifically say 'cheap 12 point'. And I also said 'when things go flying'. Specifically, I've had issues with 1) Costco distributed Crescent brand sockets, bought around 2004 (I like the ratchet a lot, 72t, very smooth, has withstood a 3 ft pipe, the sockets not so much). And 2) HF double box end offset wrenches bought in 2009.

I have lots of sets in 6 and 12 point. I personally use 6 point. 12 point is reserved for 12 point bolts, square bolts, or wrenches when I can't get a 6 point wrench to fit.

I do wonder if those whom have had bad experiences with 12 point are using older, or cheap or worn 12 points. And those who have not are issues with 12 point are using higher quality stuff (i.e. flank drive/surface drive stuff)

Except with Honda oil drain plugs. Has anyone noticed that Honda oil drain plugs are 'soft' and tend to start to round over time? I also wonder if the faster has a lot to do with rounding off.

 

[tyndall]

Your picture is pointless because it is possible to round off a fastener with either type of socket/wrench. What I said was 100% factual and true. Maybe you missed the part where I said "more likely".

You said:

A 12-point will definitely be much more likely to round off the fastener because it puts more stress on the "points" and less on the flats.

It doesn't. Your statement is 100% false. You ignore multiple tests that prove they both contact the fastener on the flats the same. They will both take the corners off the hex starting at the same point. Only after the fastener has failed (rounded) will the 6 point offer any advantage. Even then, a rounded fastener is not capable of receiving it's full rated torque. If sockets and fasteners were precision machined to a perfect fit, maybe this would be different. Right now, with loose fits and advances like flank drive, most of the wall in a 6 point is not doing anything until the fastener rounds, then it has a weak wedge effect. It didn't make it less likely to round.

Any mechanic worth anything understands that a 6-point tool is designed for a 6-point fastener. There's really nothing else for me to say if you don't at least understand that basic fact.

Agreed. A 6-point tool is designed for a 6-point fastener. A 12 point tool is designed for 6 or 12 point fasteners. If 6 point was superior for pro use, most 3/4" drive and up would all be 6 point. And why are 12 points in smaller sizes as popular as they are, considering that 12 point fasteners are much rarer than Torx?

 

[GirlnAgarage]

I also wonder if the faster has a lot to do with rounding off.

Sure the nut has something to do with it. In all these 'these wrenches ****' threads no one seems to measure the nut which is the other half of the equation. The wrench can't be wrong until it fails on a nut or bolt. Least that's when it hits the fan.

Tonight I measured some 1/2"-13tpi nuts, brand new. I use a 3/4" on them. Stupidly enough my 19mm measures larger than the 3/4" or I'd use it. The nut flat (hah I said nut flat) measure at .742". That .008" does add up. My 3/4" Cman RP measures .752" and the SO OEX at .755".

Anyway, my thoughts on nuts/bolt heads and wrenches - it's like when someone gets pregnant. Takes two to tango.

 

[ajchien]

I have no idea, but I wanna play for fun. 6,12,6,6,12,12. How'd I do? (PM would be cool, Then others could still make guesses

I got 4/6 right. Better than 50/50!

 

[Even Steven]

It doesn't. Your statement is 100% false. You ignore multiple tests that prove they both contact the fastener on the flats the same. They will both take the corners off the hex starting at the same point. Only after the fastener has failed (rounded) will the 6 point offer any advantage.

Are you familiar with AS-954? I doubt it, because you'd understand that it requires 12-point to conform to the requirement of AS870, meaning that they shall transmit torque to the fastener without bearing on the outer 5% of the fastener's wrenching points. Now think about that for a moment. There would never be a conformance standard created unless there was an issue in the first place. And the issue is that 12-point tools do not put the same stress on the same surface area as a 6-point tool used on a 6-point fastener. Sorry, but you don't know what you're talking about.

 

[Even Steven]

If 6 point was superior for pro use, most 3/4" drive and up would all be 6 point. And why are 12 points in smaller sizes as popular as they are, considering that 12 point fasteners are much rarer than Torx?

I never said 6-point is superior. I simply said it is much more common.

And 12-point fasteners are not popular, despite your claim. However, they do have their advantages. For example, we often see 12-point used to attach heads to an engine block. Why? Simple--one of the most common reasons is because the head of a 12-point fastener is often smaller than an equivalent 6-point fastener. And when it comes to space restrictions that we see on headbolts, the choice of 12-point becomes obvious. Plus, using a 12-point socket on a 12-point fastener will allow excellent torque transmission without damaging the fastener.