Certain things like bikes, cars, and furniture use hexagonal bolts for fastening. Hex bolts can only be used with the right diameter key and they don’t slip like Phillips and Flatheads. Also, the hexagonal tip keeps bolts from falling so you don’t need a magnet to hold your fasteners. Furthermore, it’s easy to identify which Allen key you need for each fastener, and you can use ballpoint hex keys if you need to work at an angle.
Since the hex bolt design is so practical, why don’t we use this type of fastener for everything? Why don’t we see hex wood screws and hex drywall screws ?
Edit : I’m asking about fasteners in general (like screws, bolts, etc)
In: Engineering
You can and do! A lot of batten screws and decking screws come in either hex, Robertson (square) or torx.
The answer as to why we don’t is something you kind of already covered, the hex head or 6 sided bolt requires a specific bit, sized appropriately, now on your small scale that’s okay, but on the scale of building a house, building or in a furniture assembly shop? Imagine how annoying it’d get to have even just *two* different sized hex heads instead of a Phillips #2 bit.
Also, in most applications of Philips head, the amount of downward force required to not strip the head is easy to provide. When it isn’t, and the screw is designed to provide the majority of torque, that’s when a different bit is required. And yes, I know that screws drive themselves in, but you still need to start it with some downward force, and apply downward force to keep the bit in the key.
You also have cost as a big consideration. The beauty of Phillips and flat in comparison to torx and hex is that stamping it into the head of a screw is much, much cheaper and easier to do in comparison to stamping an equivalent hex or torx key. Also, if the screw has a tapered head, well, you’d need to have a substantially larger head, or have a key depth so shallow the amount of torque you could apply and the ‘holds itself on’ benefits become *worse* than Phillips.
Personally, instead of giving up on Phillips, get better quality bits, and make sure you’re using the right one. I *hated* Phillips until I got a set of proper, high quality drivers, now I rarely if ever strip screws.
Hex head screws do slip, just less than Philips/flat but more than Torx or possibly Pozidriv (I don’t have much firsthand experience with Pozidrive). [This site has a nice illustration](https://rtstools.com/why-torx-bolts-are-better-than-hex-bolts/) of how torque is applied on Torx fasteners vs hex which allows for more even pressure distribution. Basically hex heads apply most of the force to the points and not the flats of the fastener so they’re less efficient compared to Torx.
Hex also has the hitch that there are both SAE and metric sizes so you effectively need two sets of bits/wrenches if they were in more widespread use. At least with bikes and Ikea they’re always metric or at least have been in my experience.
In general I’m guessing you don’t see hex as much because if Philips heads won’t suffice manufacturers just go right to Torx and skip over hex which would sit in the middle.
Hexes are more expensive and much easier to overtighten. You can easily break wood or drywall with them. You need to use the right size driver for each size of fastener or you’re liable to round it which is a problem, especially if you have both imperial and metric tools around. Slotted screws are the OG and they are nice because you can make a slot in a damaged head and even use a handy bit of flat metal if you don’t have a screw driver. Phillips are an abomination. Robertson screws are great but:
“Robertson had licensed the screw design to a maker in England, but the party that he was dealing with intentionally drove the company into bankruptcy and purchased the rights from the trustee, thus circumventing Robertson. He spent a small fortune buying back the rights. Subsequently, he refused to allow anyone to make the screws under license.”
When Henry Ford wanted to use Robertsons he demanded an exclusive license in the US. Robertson told him to go pound rocks so you don’t get them much in the US either and instead have to make truck with the Phillips and it’s spawn.
>Since the hex bolt design is so practical, why don’t we use this type of fastener for everything? Why don’t we see hex wood screws and hex drywall screws ?
Because when the hex socket was invented, it was patented, so you had to pay a licensing fee to manufacture cruise with hex sockets. That made them more expensive, and because people were already doing things with flat head and Phillips drives, they didn’t see the reasoning behind paying more when they could do an adequate job with less money.
Some of the things that you list as desirable features of hex socket screws actually make them less useful for some applications. If you just kind of randomly jam a Phillips screwdriver that’s approximately the right size at a Phillips head screw, it will tend to center itself and you can drive the screw without having to carefully align things. If you are somebody like a drywall installer who needs to drive literally hundreds if not thousands of screws a day, your productivity will decrease if you use hex socket screws instead of Phillips heads, because you will have to spend more time aligning your screwdriver. Slotted head screws have advantages over hex socket screws too, like the fact that you can drive them with almost anything as long as it’s flat, like a coin or your fingernail. You can’t really do that with a hex socket screw.
Also, like many other choices in industry, and like evolution in living things, what is standard is not necessarily what would be optimal if you started from a clean slate. History matters. A company which had the equipment to manufacture slotted screws might not be able to use that equipment to manufacture hex socket screws. The people using a bunch of screws had screwdrivers for slotted screws, but would have to buy new screwdrivers for hex socket screws.
In addition to other points, Philips screws will strip before they break. It’s so easy to shear the head off a small socket head screw, and once that happens good luck.
Hex bolts can most definitely strip and wear out.
It really depends on the sizing tolerances of the tool and the material the bolt is made of.
Also bolts are not very good in tight/recessed spaces because the socket driver has to be bigger than the bolt, which can affect design/engineering decisions.
Phillips apparently do have the feature that it makes it hard to accidently over torque. While I feel like that is true, it sounds like an excuse that was made up after the fact.
I can only tell you why I hate them. If you don’t put the bit in all the way, that screw is instantly junk with no chance to save it and it’s gonna be rough to get out. Also if you look up a hex bit set, they are like 24 pieces. There are only like 4 standard Phillips sizes, and I have never needed a ph4 outside of manufacturing work. Flathead is even more universal, to the point where sometimes you can use a coin or just scrap metal in a pinch.
Normal home use is more about convenience than being the best. I would rather know 2 screwdrivers can handle 80% of my home work, then need an entire toolbox just to take screws out/in.
The star (torx I think) screws are actually my favorite tho you need an entire set much like hex bits.
Answer: They kinda do make them.
Hi, hobbyist woodworker here and my preferred wood and deck screws all use a torx head (same advantages as hex without as much camming out.)
They sell em at all the big box hardware stores around where I’m at in the southern US.
The tools needed for hex nuts are compatible with the tools needed for hex bolts and hex lag screws. (I have not seen a socket head lag screw in the wild.) Further, a pair of adjustable wrenches can handle any of these and be the only tool you need to have handy. So hex becomes a bit easier to repair in the field.
The tools for socket head cap screws are not compatible with nuts or hex lag screws.
There’s more history with hex bolts, so people tend to expect them and have the right tools available. So there’s some inertia there.
Hex bolts can be accessed from the side, which can be an advantage for repairs in tight spaces.
Lastly, the heads on socket head cap screws are generally taller then their hex head counterparts. Easier for us meat sacks to get caught on them.
Others have pointed out that it can be problematic when you don’t know whether a socket head cap screw is metric or SAE. You have this problem with hex bolts as well though, it’s just that there’s the option of an adjustable wrench for hex bolts.
The additional complexity of a socket head cap screw, in assembly and repair, tends to favor it’s use in more expensive applications. So they tend to be available in higher grades, rather than lower grades, which affects cost.
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