Some hex tools have ball hex ends, others are straight.
There are pros and cons to both styles. Sometimes they can be used interchangeably, but that’s not always true.
Here’s a quick example I just uploaded to our Instagram channel, shown an application where you NEED a ball end hex tool, either in the shape of an L wrench, T-handle driver, socket, or other type of driver.
It can be possible to get a straight hex tool in there – the short arm of an Allen key – but it’s not going to work easily, quickly, or effectively, due to a highly restricted arc swing. In other words, let’s say you do get a straight hex tool in there. But will you be able to turn it?
The second image in that Instagram post shows the advantage of ball end hex keys, which is the fastener access angle. You don’t need to approach the fastener directly, from 90°.
This image, from when Wera released new ball hex keys, shows that you can fit a ball end fastener into a socket cap screw, or other hex fastener, from an angle.
The downside is that you do lose some fastener engagement. For that reason, ball end hex keys are not ideal for higher torque applications.
You will often see ball ends on the long arm of hex keys, and straight hex ends on the short arms. That way you can have an easier time turning a loose fastener, and rely on better engagement and higher torque delivery on tight ones.
There are ball end sockets and T-handle tools, but greater care needs to be heeded when using them. Ball hex ends CAN break off, and when they do, you’re in for a world of trouble.
Bondhus, a good USA brand of hex tools, doesn’t sell T-handle ball hex drivers in certain smaller sizes, due to the higher likelihood of breakage and a bad day. In my set, the smallest sizes have straight hex tips, then there are 2 ball end hex drivers with smaller handles (to limit torque levels), and the larger sizes have ball ends and regularly sized handles.
There are some tasks that you should use straight hex tools for, others where you almost need to use ball end tools, and many where you could use either one.
Personally, if I can use a ball hex tool over a straight hex tool, that’s what I do. I don’t always need to approach fasteners from an angle, but the freedom to stray from perfectly straight-on allows for a little flexibility in hand motions.
But that’s also not a strict tendency. Sometimes I prefer straight hex tips, even in lower torque applications, due to better fitment with certain fasteners. I’ve still been meaning to take measurements, but I think that the finish of those Bondhus hex keys are out of spec.
Some hex fasteners are a little shallow, and I’ve found that they work better with straight hex tips. Driving them in just feels a little more confident.
It’s not really a discussion about which is better. In the same way that you might sometimes use the box end of a combination wrench, and other times you’ll need the open end wrench, sometimes it’s good to have ball end and straight end hex tools available.
And as you can buy wrenches with two open ends, and those with two box ends, you can buy combination hex tools (mainly L wrenches and “P handle” drivers) with straight end tips, although they can be less visible at retailers, as talked about in today’s earlier post.
You won’t find L wrenches with two ball hex ends, or at least you really shouldn’t, since ball hex ends are not usually recommended for higher torque applications.
That all said, which style of hex tips do you find yourself using most? Ball or straight?
I recently used a ball-end for the first time as one came with a piece of furniture. I was excited to try it out and it was a pleasure to use. I only use my hex keys once in a while and so I don’t see myself investing in a full set. With that said, if I do upgrade the stanley set that has served me well, it will definitely be for a ball-end set.
I use socket head cap screws for jigs and setup, and I love ball end drivers for that. I’ve been buying Wera ball-end screwdrivers for the sizes I use.
I do all my tightening with straight hex drivers though.
Straight head as much as possible…for longer fastener life.
I did some unfortunate violence with a ball-end allen key to a hex socket fork tube plug screw that was seized pretty badly. I didn’t have straight tipped keys at the time, and the short arm wouldn’t reach because of the axle bore. By the time I realized what was going on and went to the hardware store for longer straight keys, I had chewed up the socket badly enough that the straight keys wouldn’t turn the screw either. I eventually got the screw out with a borrowed impact wrench and a sunex hex impact socket. The sunex ones have an intermediate length that worked perfectly. Their 20-piece SAE/metric half-inch drive set is just under $80 on Amazon. It’s really handy to have around for automotive stuff.
Thanks for the link, I will try these!
I work on cycles as well, always looking for a better tool to use with impacts!
We also ran into some socket-head screws that had a “security” pin in their center – to make them more tamper resistant.
I have a set of bits for those but no keys. I find I’ve not needed a key for it.
back when I worked RC cars I knew guys that kept a set of expensive ball end hex drivers that had all sorts of labels on them.
I used a set of bondhus ball hex keys. so I had ball end and straight end on the same bit. Love that combo – won’t buy anything else.
BUT – I also keep a full set of metric and SAE hex bits for my ratcheting screw drivers and now my power drivers.
SO I use that too. In fact I will without hesitation put a 5mm hex bit in my dewalt impactor – set it to 1 – and use it to run in hardware for furniture – like my baby’s crib or the table I put together last week. In both those cases I also had my hex keys as final backup and tightening.
I haven’t had too many problems with my Wiha hex bits but the only thing I run into all the time is the fastener head of the screw itself. Particularly on stop collars where the socket in the fastener head is so close to the outer ridge or the metal is so soft, I always seem to have them flower out and good bye engagement. I think I am going to try those Wera ones (i think those are the ones) which bite into the walls instead of the points of the socket head and see if that stops the constant stripping issue I have.
What brand of shaft collar do you typically use? I haven’t had issues like that with set screws before, or on clamping collars either.
Cant say that its any specific brand, it may be just the size and/or material. Mostly these are on 3D printer components and small electronics (1.5-2.5 mm hex sizes) and I think most of the material consists of aluminum which may be part of the problem itself. Since there is so much fiddling involved these are getting set and reset all the time and i frequently seem to run into the heads camming out. I don’t think its a fault of the Wiha hex keys themselves, but as I mentioned I think the better path are those which apply pressure to the walls instead of the pointed corners which would really make a difference I think.
“You won’t find L wrenches with two ball hex ends, or at least you really shouldn’t, since ball hex ends are not usually recommended for higher torque applications.”
You must be psychic Stuey as for some reason I was looking at hex wrenches the other day and came across this.
interesting – and note the ball end on the stub side is different than on the long side.
That long side is a standard looking ball end – but the stub side is much shallower.
Makes some sense really there are times you have a hard to reach spot you need some torque on. I also like that they short arm is at a bit of an angle not a hard 90. Might be worth a try.
There is a 4th screw on any BMW e90 diesel engine’s air filter housing, which can only be removed by a ball end hex key / long ball end hex key socket. No other possibility to access it. For rg. Hazet 986KK-5 or gedore IN 30 LK 5
…Interesting… I didn’t even know this was a debatable topic. I thought Hex vs Ball End Hex was the same argument as Philips End or Robertson screwdrivers. The answer is pretty moot. You can’t use a Robertson on a Philips End screw (Or vice-versa) any more than you can use a Hex End driver where you can only fit a Ball-End Hex driver. The sole difference between the two arguments is that there’s no vice-versa situation. You can use just ball-end hex drivers without any difference, but you can’t use a hex end driver where you can’t reach the fastener with it.
Is this really something that people debate in the tool industry? I don’t mean like Apple versus PC type arguments, but is this really… a THING? Isn’t this rendered moot by the application?
I mean, personally, I like pretty much any fastener that isn’t a flat head, simply because a flat head torques out of the slot if you so much as breathe wrong. The vast majority of all the bit heads I have are deliberately bought just in case I encounter THAT fastener head. I was not aware that Hex vs Ball-End Hex was even a debate.
It certainly is.
Ball hex are rare creatures up here.
some people don’t like the slop or lack of engagement a ball end hex makes and won’t use anything but a squared off hex. I know some people like them – they are what I call old school.
I have ball end L-keys and ball end T-handles but really only use the L-keys. The ball end of the T-handles really only has the advantage of being slightly longer than the L-key, otherwise they don’t do much for the ball end since you’re not supposed to crank down on it as mentioned. Maybe you get more control but I haven’t run into anything that the L-keys didn’t work fine for.
I do prefer using the straight ends of hex keys, since obviously they fit better, but I’m glad to have sets with the ball end. They do provide a type of access you can’t get otherwise and sometimes even if it’s not absolutely necessary, they’ll save you hours of work so you can loosen fasterners you’d have to remove other parts to get straight-on access to otherwise.
Given the price of a set of long arm ball-end keys, it’s not a bad investment at all and a good thing to have around, even just to have as a second set, a long arm set, or new set with an organizer.
Bondhus has a stubby double ball end hex keys now. The head is at a 100 degrees instead of 90. What are your thoughts on those? To me it seems like it might wobble around too much in higher torque applications.
I don’t mean high torque, but just as you apply more pressure to the key it seems like it would start to shift around in the fastener
The larger the fastener, the less likely a ball-end may damage or fail. I have personally used 18mm ball-end bits at a 45deg angle to break free a fastener that was likely over 200 ftlbs. Sketchy, but it works.
After 40+ years as a tool room machinist, 90% of Allen wrench use was straight end was used. Of course nearly all was an unobstructed views. There were times when use of a ball end was necessary. Surprisingly, the when shop operators needed to use a ball end they used a “cheater” to snug it up. Over tightening was the norm with both straight and ball end resulting in rounding the straight ends. Even with the use of “cheater” pipe nipples, I’ve never had to deal with broken ball ends jammed in the Allen head. On rare occasion a 1/2” ball end was need to get into an extremely tight location. It was tough to find that beast at the time so we had grind the ball, harden it then temper it. It was a learning experience to say the least. With a 4’ cheater pipe in hand, It worked.
Given the choice, a straight end was first choice.
As a few have mentioned already I think both have their place. The greater torque on straight ends is definitely an advantage, also the fact that it will hold your fastener straight to insert it. The ball ends will save your life here and there, but I’ve broken a few. Just a couple weeks ago trying to tighten a sprocket taper bushing between the gearbox and the sprocket I broke one. Thankfully the socket head was deep enough that I pushed the broken ball deeper and used another wrench to take it out and replace the fastener. But I haven’t always been that fortunate.
I have had ball ends twist off on 5mm ac valves, so I now avoid them and stick with straight hex. For lighter duty? they have their place.
Gotta have ball end , just to have around in case of need. I prefer t handle straight tip whenever possible
I’ve had the same sets of Bondhus L-shaped wrenches with a ball on the long end and flat sides on the short end since I was a bicycle mechanic back in the late ’90s – can’t say enough about the quality, these suckers have taken some abuse.
On topic – ball end for quick spins to snug a bolt up, straight end once it’s time for torquing things down. On rare occasion I need to get in a tricky spot and use the ball end with the closed side of a combo wrench as a cheater bar to break or tighten a stuck bolt, but I try to avoid that whenever possible. I had no idea there was a debate over how to use these things, just always took it as obvious that you use a flat key whenever possible and the ball end only in a pinch…
Working on industrial equipment with lots of SHCS, BHCS, and FHCS, I find that I really need both ball and straight drivers. In some cases the ball driver is the only option to reach the head of the fastener. Downsides are wearing out the internal hex. One application requires multiple in and outs on a series of 8-32 SHCS. Using a ball driver on those all the time will kill the internal hex in pretty short order.
Another nice feature of the straight is the ability to use the driver (straight driver with a handle) to hold the fastener securely and pilot it into a hole that may not be very easy to get to.
I’d like to add “judgement” to the mix.
I volunteer in a bicycle coop and find a lot of the fasteners are either low quality, corroded, or both. Whenever possible I use a straight end to break the fastener loose, then may switch to the ball end when necessary based on the angle. But I don’t introduce the ball end wrenches to patrons I’m assisting unless there is a real need and they come with a lesson. Most have very little, if any, experience and I view part of my job is to not make them pay for the lesson’s I already have so they can learn to enjoy the work, not be frustrated. They will find enough of their own lessons if they stick with it LOL. All the hex wrenches put out for their use are straight end.
Park tools are the most common in a bike shop, and thy sell both straight end “tee” handle wrenches and with a ball on the long end. But the top of the “tee” is straight for breaking fasteners loose.
I think one can’t “have it all in one” solution when it comes to hex/allen heads:
There are some fasteners that need a ball-end to reach/install. And other that you have to be nuts to use a L-shaped hex wrench (fingers of steel?).
I only use ball allen drivers with screwdriver type handles. Perfect for running a bolt down quick. Then i finish with an L or a T. My T-wrenches are always straight. They always wear anyway and you can shorten and file them if you dont heat them up and lose the temper. I had a 6mm head allen bolt in a recessed hole that I needed to loosen but could not get straight access to without removing a lot of other assemblies. I used the ball end allen T and the ball broke off in the bolt. Spent the next half a day removing the afore mentioned assemblies, ruining four new hardened drill bits and dulling two prick punches. Eventually got it out with a torch and needle nose vise grips used inside out. After ten years I still have that bolt on the workbench as a happy reminder. I don’t use the ball allens to loosen anything. The steel they use is hard enough to not want to take a drill bit but difficult to shatter.
I’m getting a few additions for my motorcycle tool box & allen keys are on the list particularly the socket variety, I already have a set but looking for long reach of 100mm. Looked on eBay for a set but the only half decent set was made by Sealey but guess what – they were the ball end type!
I was struggling with the thought of buying them but eventually found a set by Teng with straight ends.
This thread helped me to focus on what I already knew which is:-
Unless a fixing is very hard to get to or not very tight then always use a straight end!
It’s easy to get confused about it when most of the allen keys they sell have ball ends on the long shaft but rounding off a fastener is a world of pain & in my books not worth it.
What this really boils down to is that we need to have more than one type to hand as they all have their place & unfortunately this applies to all the tools across the board which is why sometimes you have to seriously consider if it might be prudent just to take to the professional…
Check out Motogadget T-handle. It has a 3/8″ wobbler on the end. I use that with straight hex and torx sockets. I good solution instead of using ball ends. Ball ends are in my inventory just in case. I don’t like out they blow out the inside hex of the fastner.
Now… where can I find Extra-long reach ball end and straight hex tools? I need them at least 18″ and adaptable to torque tools (1/4″ hex drive). Solid piece, not welded or soldered.
I don’t think you’ll be able to find something like that, especially not a solid piece.