Why Allen/Hex Keys Commonly L-shaped but not Philips / Flat / Torx?

[oldschoolcraft]

Why is it that the most common implementation of hex keys is a set of L-shaped tools. But only for that fastener type. Yes, there’s are some torx l-shape keys but that’s the rarity. Torx comes on screwdrivers. Yes, there’s hex-shaped regular handled “screwdrivers” but that’s the rarity.

Many of us have multiple ways of turning fasteners, but the default shape tool seems to be L-shape for hex, and regular handled screwdriver for torx, Philips, flathead.

How did this come to pass? My best guess is there’s so many different hex sizes compared to Philips or torx, and at smaller sizes at or below 10mm or 3/8“ that low torque is sufficient so to save space in toolboxes, they made these small single size allen keys that can fit in one compact package.

 

[rust in the eye]

Something I never questioned. I'll guess it is a function of the amount of torque needed for typical set screw fastenings.
I have some "screwdriver" type handles but often do final tightening with a L key

 

[Spud McGee]

I do have plenty of torx L shaped tools. They are round or hex, except torx at the tip.

And a think thats your answer, or at least part of it. Its easy to heat up and bend a piece of hex bar. It is not easy to bend a bar with a star profile. The little points would deform and/or you'd get splitting and stress risers.

It becomes a cost thing. Its cheap to produce hex L shaped, because you can buy bar thats the hex shape, heat it, bend it, cut it, done. The machine can do that over and over.

If you want an L torx, you start with a hex/round, heat it, bend it, cut it, then somehow form the star on the ends. Its a more involved process. They will cost more to produce than your normal allen key. And if you're spending that much more to produce them, you may as well make a T handle or something?

A side effect of them having to come in and create the torx ends after the fact is these tend to have different sizes on each leg of the L. They are commonly included with optics and scopes. The optic uses 2 sizes of fasteners. You get 1 tool than can tighten all the fasteners required for that optic.

 

[Bubba Fett]

Hex keys are thought of more as wrenches than drivers. They are designed for leverage/torque more than speed. There's a wide range of sizes in both Inch and Metric, so they tend to some in larger sets, and typically have a simpler design.

Internal hex fasteners are often used as inset screws, adjustment screws, as well as higher torque screws and bolts in places where an external hex bolt is too bulky. This, along with the relatively simple manufacturing process for Allen wrenches/Hex Keys is the major reason for the wide range of sizes. They can simply take a lot more force before camming out or stripping, and they are easy/cheap to make.

You can find L-type Hollow Ground ground and Phillips in L-type wrenches, but they simply don't work as well due to the tip geometry. Torx is easily available in L-keys as well as traditional drivers.

 

[Leaflessshadetree]

I have phillips and flat in the offset style
Use them and you will understand why you don't find L shaped.
Torx L shaped keys are fairly common as are T style, folding, screwdriver, socket and bit styles. Same as allen.

 

[larry_g]

I believe that if you look at the recommended torque spec for a given sized fastener you will find that the SHCS is far above the soft screws that commonly have a Phillips or straight slot head. SHCS's are usually high tensile materials and torqued to a high force. The length of an L shaped hex key will give the mechanic the leverage to tighten or loosen the fastener. Think about having to use a nut driver vs a box wrench on common nuts and bolts. The wrench gives the leverage that a nut driver cannot.

lg
no neat sig line

 

[Dave455]

Phillips and Slotted screwdrivers need downforce so that they don’t slip out. You can’t really apply downforce very well with an L shaped key.

L shaped Torx keys are quite common. These Wera are my current favourites.


I tend to favour screwdrivers in the smaller sizes, but L Keys or socket bits for the larger sizes. I do the same for hex keys.

I’m in agreement with Bubba Fett above - the L keys are more of an alternative to a wrench, and that’s how I use them!

 

[oldschoolcraft]

What’s the difference between a wrench and a screwdriver? A couple of you mentioned the hex is wrench-like but I’m not sure what that means. What actually makes something a wrench?

 

[PelicanPines]

What’s the difference between a wrench and a screwdriver? A couple of you mentioned the hex is wrench-like but I’m not sure what that means. What actually makes something a wrench?

Screwdrivers... drive screws
Wrenches... turn nuts

 

[larry_g]

What’s the difference between a wrench and a screwdriver? A couple of you mentioned the hex is wrench-like but I’m not sure what that means. What actually makes something a wrench?

If you pay attention most times "wrench" is preceded by a descriptor such as pipe, combination, monkey, box and many others. A wrench generically is for turning something. The descriptor is usually for what it may turn or the form it takes.

lg
no neat sig line

 

[oldschoolcraft]

Screwdrivers... drive screws
Wrenches... turn nuts

Hex keys in my experience are used to turn bolts with female hex heads.

Are you using screw and bolt to mean two separate things? Not trying to be overly technical just trying to learn!

 

[PelicanPines]

Hex keys in my experience are used to turn bolts with female hex heads.

Are you using screw and bolt to mean two separate things? Not trying to be overly technical just trying to learn!

It depends of the head of the bolt... if it can be turned with a screwdriver ... it's a screw. Most bolts in my history has a hex head... which makes them Wrenchable. Hex keys to me are wrenches.

Are there screwdrivers to turn hex both male and female...?

Yes... for those... I would say they turn Hex Screws with a female head. A Hex Screw with a male head... would be wrenched. Or nut driven. Not screw driven.

 

[neophyte]

What’s the difference between a wrench and a screwdriver? A couple of you mentioned the hex is wrench-like but I’m not sure what that means. What actually makes something a wrench?

Wrenches usually have a handle set at around a 90 degree angle from the axis of the fastener.
Screwdrivers usually have a handle that is inline with the axis of the fastener, and usually centered on that axis.

 

[oldschoolcraft]

It depends of the head of the bolt... if it can be turned with a screwdriver ... it's a screw. Most bolts in my history has a hex head... which makes them Wrenchable. Hex keys to me are wrenches.

I thought the difference between a bolt and a screw was that a screw has a pointy end and a bolt has a cylindrical shape all the way down to the end.

I didn’t think the actual shape of the head mattered, just the shape of the bottom of the fastener. Am I way off?

 

[PelicanPines]

We were talking about screwdrivers and wrenches... "Head Matters"... Lag bolts are pointy ... if you want to use that term. The screwdriver wrench argument can be summed up with the shape of the head.... oh ... and its ***. *** matters too.

 

[garfunkle24]

It depends of the head of the bolt... if it can be turned with a screwdriver ... it's a screw.

Nope. Well maybe. If we're being specific: All male fasteners with external threads designed to provide axial tension are screws. A screw (or capscrew) only becomes a bolt when used with a nut. So really, a wrench can be a screwdriver and a screwdriver can be a wrench.

But is a machine screw, used with a nut, a bolt or a screw?

 

[vwpieces]

Flat and Phillips require pressure to avoid cam out. Hex and Torx don't.
Making an L shaped screwdriver harder to use.

 

[Leaflessshadetree]

We were talking about screwdrivers and wrenches... "Head Matters"... Lag bolts are pointy ... if you want to use that term. The screwdriver wrench argument can be summed up with the shape of the head.... oh ... and its ***. *** matters too.

If you want to be more unsure google the definition of Cap Screw or "cap screw vs bolt".

In this thread "screwdriver" is a tool where your grip is around an axis coincident with the axis of the fastener. Wrench is a tool where your hand is offset from that axis thus creating the mechanical advantage of a lever.

 

[oldschoolcraft]

Flat and Phillips require pressure to avoid cam out. Hex and Torx don't.
Making an L shaped screwdriver harder to use.

That makes sense. So the difference is:

screwdrivers provide both downward as well as rotational pressure. Lacking the downward pressure, you’d be unable to provide the necessary rotational pressure.

hex and torx have so much internal surface area that you don’t need the Downward pressure and in fact if you did apply downward pressure, you’d be making it harder to remove the fastener!

 

[lolaetype]

Phillips and Slotted screwdrivers need downforce so that they don’t slip out. You can’t really apply downforce very well with an L shaped key.

That would be my explanation as well.

 

[PelicanPines]

What if... you use sockets with screwdriver inserts... is it a screwdriver or socket?

 

[Junkdrawer Dog]

I have phillips and flat in the offset style
Use them and you will understand why you don't find L shaped.
Torx L shaped keys are fairly common as are T style, folding, screwdriver, socket and bit styles. Same as allen.

Yes...you would get those in the big Craftsman screwdriver sets. They would migrate to the back of the screwdriver drawer, only to be used about once per decade for some oddball situations.

 

[oldschoolcraft]

What if... you use sockets with screwdriver inserts... is it a screwdriver or socket?

You’d still have to apply downward pressure to avoid camming/slipping the bit out of the fastener head. It’s just that the rotation would be done using a ratchet in a perpendicular motion/

 

[larry_g]

According to Machinery's Handbook "a screw is tightened (or torqued) by its head and a bolt is torqued by a nut." To remember that think of a carriage bolt or a plow bolt. Yes you can put a nut on a machine screw. Thread form does not factor in on deciding whether it is a screw or bolt.

Carry on with your own ideas.

lg
no neat sig line

 

[oldschoolcraft]

According to Machinery's Handbook "a screw is tightened (or torqued) by its head and a bolt is torqued by a nut." To remember that think of a carriage bolt or a plow bolt. Yes you can put a nut on a machine screw. Thread form does not factor in on deciding whether it is a screw or bolt.

what if you hold the nut while turning the bolt? Does that make it a screw? At least temporarily?

Maybe it identifies as a trans-fastener that is torque-fluid based on whether you are holding its nut or if the nut is tucked away at the time?

 

[finn]

Where did you get the idea that “L” shaped torx wrenches are rare? I have at least two sets, and maybe more. One is from HF, and the other is a Masterforce from Menards.

They’re as common as dirt.

 

[F-22]

Torx L keys are very common. I think torx screwdrivers are more common than allen/hex screwdrivers because torx is also used for wood screws where a screwdriver is a lot more useful to turn it than an L key (and also to push/drive it into the wood).

In some places in Europe, regular outside hex "wrenches" are also the L key style:



I have a couple. I think a classic wrench is more versatile, but when these can be used they are really nice and more comfortable to use. In some cases they have just enough clearance to turn stuff where a classic wrench won't work well and where a socket and a ratchet is too bulky. Really like them for 5mm, 5.5mm, 6mm, 7mm and 8mm sizes to tighten small stuff like a hose clamps (though a screwdriver or a T handle is nice in that case too)

 

[PelicanPines]

 

[Steve_P]

According to Machinery's Handbook "a screw is tightened (or torqued) by its head and a bolt is torqued by a nut." To remember that think of a carriage bolt or a plow bolt. Yes you can put a nut on a machine screw. Thread form does not factor in on deciding whether it is a screw or bolt.

Carry on with your own ideas.

lg
no neat sig line

This is the correct notation in the engineering world, and has been for many decades. Saying that, if you go into Ace Hardware and tell them you need a 1/2-13 X 2" long hex head cap screw, you will get confused looks.

Pretty much 99.9% of what everyone calls a bolt is actually a hex head cap screw, or HHCS. The terminology used in an engineering bill of materials doesn't change because you put a nut on a SHCS, or HHCS; it's still a screw. Same when you order them from McMaster- they don't list them in another section and call them bolts if you want to use a nut on them. But with something like a carriage bolt, you have to use a nut on it, so it's a bolt.