More info about screws than you could possibly require
March 22, 2016 10:43 AM   Subscribe

 
"Square Recess"? It's called a Robertson. It's the best one. Catch on already, non-Canadians.
posted by Sys Rq at 10:48 AM on March 22, 2016 [25 favorites]


There's an expanded version as well, which covers things like security screws too.
posted by bonehead at 10:50 AM on March 22, 2016 [3 favorites]


I wish that all screws I came across were Torx. I'm tired of stripping screw heads in my home mechanic endeavours. Torx grips nicely (and I already own the tools, Torx being common on European cars).
posted by Harald74 at 10:53 AM on March 22, 2016 [5 favorites]


But this doesn't have the weird one I ran across the other day which was a slotted screwdriver with a diagonal square in the middle. (It wasn't a combo screw, the actual driver bit was like this)
posted by ckape at 10:54 AM on March 22, 2016


Robertson or GTFO.
posted by Sauce Trough at 10:55 AM on March 22, 2016 [12 favorites]


Interesting! New-to-me info was that JIS screwdrivers fit Phillips screws. Maybe I will just get rid of all my Phillips screwdrivers, and thereby protect any JIS screws coming into my garage.
posted by elizilla at 10:55 AM on March 22, 2016 [2 favorites]


Square drives are great, but yeah, the bit can get bound up in them as TFA points out, which is a pain.

Torx/star drive are my absolute favorite, but you can't just walk into most US hardware stores and find what you want. The big boxes usually have exterior decking screws and maybe one or two sizes of non-coated ones and that's it. So if you aren't lucky, you either gotta order on Amazon and wait two days to start your project or else get a box of those Phillips/square hybrids and go to work.

"Square Recess"? It's called a Robertson.

As the link says, not all squares are Robertsons. Outside of Canada, that can cause problems if you wind up with a Robertson screw and a non-Robertson square bit or vice versa. Which is why I love Torx. There's no confusion, the bits never get bound up, and they almost never cam out/strip.
posted by middleclasstool at 10:59 AM on March 22, 2016 [4 favorites]


Robertson's idiocy about his patent was a grave disservice to the fastener world. Phillips design should never have left the factory floor. Fine design for a cam-out head. Terrible design for every other application.
posted by five fresh fish at 10:59 AM on March 22, 2016 [6 favorites]


Robertson.
posted by parki at 11:00 AM on March 22, 2016 [1 favorite]


What about the weird security screw Apple uses?
posted by Karmakaze at 11:00 AM on March 22, 2016


This is awesome, BTW. I had no idea there were so many Phillips-like heads.

I also didn't know the Torq-Set's name, which I always called the Nazi Screw.
posted by middleclasstool at 11:00 AM on March 22, 2016 [2 favorites]


I bought a nice set of Vessel JIS screwdrivers for my husband a couple of years ago (this was enlightened self-interest; I maintain my own motorcycles and use the JIS screwdrivers too). It's hard to overstate how much easier they are to use. For years I thought I was, I dunno, screwdriver-impaired or something because I was always butchering screws.
posted by workerant at 11:01 AM on March 22, 2016 [3 favorites]


What about the weird security screw Apple uses?

The FBI has asked for an extension on that.
posted by valkane at 11:02 AM on March 22, 2016 [9 favorites]


"Square Recess"? It's called a Robertson.

They're different as the article points out. Robertson allows some affordances to make fitting the head in easier: tapering the bit and slightly rounding the corners. By contrast, a square drive isn't tapered and has sharp corners, though the article shows at least one bit there that's just a straight-up Robertson clone. This means that it's a lot easier to fit the bits in a Robertson socket while still being a lot more secure than other options. Robertson really was a great design.

Hex head (and then only with a ball end) or Torx are arguably the only real major improvements made since.
posted by bonehead at 11:03 AM on March 22, 2016 [3 favorites]


The Philips head is designed to camout?!
posted by rlk at 11:06 AM on March 22, 2016 [9 favorites]


When is a Phillips not a Phillips?

When it's a Reed & Prince (or a Frearson as some would call it ).
posted by MikeMc at 11:14 AM on March 22, 2016 [1 favorite]


From here:

The screw was invented in the early 30’s by Henry F. Phillips, a Portland, Oregon businessman. He knew that car makers needed a screw that could be driven with more torque and that would hold tighter than slotted screws. Car makers also needed a screw that would center quickly and easily, and could be used efficiently on an assembly line. The Phillips screw was designed so that it could be driven by an automated screw driver with increasing force until the tip of the driver popped out without ruining the screw head. So what many consider a design flaw is actually a feature (at least if you’re a car manufacturer).

I've heard tell from people in the areospace industry that the Phillips screw became really important during WW2. When the assembly lines de-skilled with the workers going to the front, and many new workers coming into the factories, the Phillips cam-out could not just save money, but also a huge amount of time. An over-tightened screw could tear the metal that it have been connecting into, meaning that the part had to be drilled out and replaced with a larger screw. Airplanes are typically made of much lighter, and so lower-strength materials, and thus were more prone to over-tightening, so a torque-limited screw was petty important there. No references for this, sorry. Just my recollection of a bunch of old engineer's tales.
posted by bonehead at 11:16 AM on March 22, 2016 [21 favorites]


Funny that most of the improved-upon variants of Phillips head have as their only drawback “might get confused with Phillips head.” If you could get rid of all the screws and screwdrivers in the world and start over, it might be easy to get everyone to agree on a screw design that’s far superior to Phillips, but history gets in the way, much like with QWERTY keyboards.
posted by savetheclocktower at 11:23 AM on March 22, 2016 [1 favorite]


Is this a good place to ask why the hell flathead screws still exist? Is there any good reason to use them? Yet just about any time I buy anything that needs to be screwed together there are flathead screws.
posted by bondcliff at 11:26 AM on March 22, 2016 [1 favorite]


I love this:

Screw makers of the 1930s dismissed the Phillips concept since it calls for a relatively complex recessed socket shape in the head of the screw; as distinct from the simple milled slot of a slotted type screw.

Phillips then called on the American Screw Company, a newcomer to the industry whose new president, Eugene Clark, personally became interested in the new product, despite the opposition of his engineers, who like others in the industry had insisted it could not be made. According to one printed report, the president of American Screw Company said: "I finally told my head men that I would put on pension all who insisted it could not be done. After that an efficient method was evolved to manufacture the fasteners and now we have licensed all other major companies to use it."

posted by ancillary at 11:30 AM on March 22, 2016 [1 favorite]


Are they cheaper to manufacture? Plus it's probably still the case that if your customer owns only one screwdriver, it's probably a flathead.
posted by We had a deal, Kyle at 11:30 AM on March 22, 2016


It's the best one. Catch on already, non-Canadians.

No, it's not. Torx and hex (aka Allen) are better in pretty much every way. There are bits that drive better than Torx, like the newish Lox, but unless you're working with very large screws, a Torx can apply enough torque to the head to twist the entire head off the screw, which means it's good enough.

That's why the Philips existed. It cams out if you over torque, which means you don't destroy the screw shaft or the surface you're putting the screw into. With modern power drivers with built in torque clutches, you don't need that, and every advantage the Robertson has, the Torx and Hex have more and they suffer bit-bind less.

More importantly, the one fastener that's closest to available worldwide? Torx. #2? Hex -- though you have Metric and US hex sizes, which means you carry twice as many bits/drivers. There's only one set of Torx. You don't have to deal with "I'm in Japan, this isn't a Phillips, it's a JIS" or "I'm in Europe, this isn't a Phillips, it's a Posidrive.* At least Posidrive screws are marked differently than Phillips or JIS, so you can tell by looking that they're not Phillips.


Look at bikes. Built in Japan, built in Europe, what do they use? Hex and Torx.

Really, 95% of the screw heads need to die. Use Torx on small, Hex on large. If you need maximum strength in the head, Hex puts fewer and weaker stress concentrators than Torx.

* Wondering why Ikea screws suck? They don't. They're just not Phillips. Get a Posidrive bit and see how much easier they are to work with. They do suck if you're using a #2 Phillips driver, because they cam out even easier than a #2 Phillips screw would. But a #2 Posidrive driver? Sets those screws nicely indeed. Just make sure you're doing that by hand or with a screw gun with a clutch, because you can easily rip the hell out of things with Pozidrive.
posted by eriko at 11:46 AM on March 22, 2016 [53 favorites]


Flatheads are cool because you can use an improvised screwdriver, like a coin.
posted by paper chromatographologist at 11:47 AM on March 22, 2016 [16 favorites]


All you torx lovers : how often to you really use them ? Because I find every torx bit I have is pretty stripped down after about 20 screws: t2, t-5, t-30, and all in between.. (Though the smaller bits shear a heck of a lot faster than the larger ones.).

That's why hex are an improvement over torx.
posted by k5.user at 11:49 AM on March 22, 2016


*ahem* it's probably still the case that if your customer owns only one screwdriver, it's probably a flathead butterknife.

I'm slowly replacing all the phillips screws in things I work on with torx/hex cap head screws.
posted by Xyanthilous P. Harrierstick at 11:49 AM on March 22, 2016 [7 favorites]


I'm always happy wearing this subject-related shirt. Why yes, I do work in IT.
posted by Abehammerb Lincoln at 11:49 AM on March 22, 2016 [4 favorites]


k5.user: i find the opposite, actually. Hex heads are deficient in that the screwdriver will wear out and round off, which will eventually damage the tool; leading to damaged screw heads if you keep using it. (which is why you should only use hex CAP screws, because you can always get those back out with a combination of a good pair of vise grips and/or grinding a blade-head slot in the cap.)

Torx, on the other hand, seem to just break the driver bit before damaging a bunch of screws in the process.
posted by Xyanthilous P. Harrierstick at 11:52 AM on March 22, 2016 [1 favorite]


I bought a nice set of Vessel JIS screwdrivers for my husband a couple of years ago (this was enlightened self-interest; I maintain my own motorcycles and use the JIS screwdrivers too). It's hard to overstate how much easier they are to use. For years I thought I was, I dunno, screwdriver-impaired or something because I was always butchering screws.
posted by workerant
Fair warning, as of ~2008, nobody manufactures JIS screwdrivers
posted by TheNewWazoo at 11:52 AM on March 22, 2016 [1 favorite]


k5.user, that may have to do with the quality of the Torx bits you're using? They have to be properly hardened, just like hex bits. Since a lot of hex and Torx heads are slightly hard (socket head cap screws, etc.), they'll rapidly tear up cheap bits.
posted by introp at 11:54 AM on March 22, 2016


I really want to read a Kate Beaton comic about Peter L. Robertson and the Great Canadian Screw that should have conquered the world.
posted by neroli at 11:57 AM on March 22, 2016 [14 favorites]


Flatheads are cool because you can use an improvised screwdriver, like a coin.

Flathead is a type of screw head that is independent of the type of screwdriver. What you mean to say is slotted head.

Head shapes can be flat, round, pan, oval, etc as seen here. A flathead screw can have various types of drive -- slotted, phillips, square drive, etc.
posted by JackFlash at 11:58 AM on March 22, 2016 [8 favorites]


Much as I love newer designs, slotted heads have one major advantage.

When you've over-torqued the screw and snapped the head off, you can cut a slot in the remaining part of the screw and back that fucker out.
posted by happyinmotion at 12:04 PM on March 22, 2016 [4 favorites]


I hate phillips and all the stupid slightly different cross-head screws. So many stupid different bits to keep track of to find the right one. Give me Robertson any day. Red, green, and yellow are pretty well all you need for any job. One of my great annoyances has been the gradual replacement of Robertson screws in hardware sold in Canada with stupid phillips screws. And then there are the crappy "Robertson" screws sold at Home Despot - poor tolerances and those things strip out far too easily.
posted by fimbulvetr at 12:06 PM on March 22, 2016 [1 favorite]


Much as I love newer designs, slotted heads have one major advantage.

When you've over-torqued the screw and snapped the head off, you can cut a slot in the remaining part of the screw and back that fucker out.


If the head broke off and you're cutting a slot in it, it doesn't really matter what kind of screwdriver it used to need....
posted by cardboard at 12:08 PM on March 22, 2016 [24 favorites]


I'm glad for the Instructables page, because back in the day, one of my favorite references for things such as non-standard screw heads was Sizes by John Lord, which described not only size standards and ranges (I believe it had an entry for penises, even), but also other types of standards as well. Sadly, it's about two decades out of print.
posted by Halloween Jack at 12:09 PM on March 22, 2016 [1 favorite]


Given all the things a "standard blade head screwdriver" is used for[1], we should probably stop thinking about them as screwdrivers, and more as destructive devices.

[1] chisels. scrapers. emergency screw removal after you've ground a slot in a part. prybars. emergency car starters [2]. paint stirrers. lid removers.

[2] ... short across the starter motor in a pinch...
posted by Xyanthilous P. Harrierstick at 12:12 PM on March 22, 2016 [1 favorite]


Flatheads are cool because you can use an improvised screwdriver, like a coin.

Also because you can freak out tool geeks by doing things like opening paint cans with the screwdriver.
posted by Dr Dracator at 12:16 PM on March 22, 2016 [6 favorites]


You know those screws that look like a Phillips, but with two of the wings extended so you can use a slotted screwdriver too? Yeah, those are called terminal block screws and of course someone has made a matching screwdriver.

I love that a screw manufacturer set out to make a universal screw, and then a screwdriver manufacture saw it and made a very-not-universal screwdriver just for it.
posted by ryanrs at 12:26 PM on March 22, 2016 [14 favorites]


* Wondering why Ikea screws suck? They don't. They're just not Phillips. Get a Posidrive bit and see how much easier they are to work with.

Hot damn, posting this was worth it for this piece of info alone.
posted by Itaxpica at 12:34 PM on March 22, 2016 [9 favorites]


In my experience, on all small wood-construction job sites in Canada, Robertson isn't just the overwhelming favourite, it's the only wood screw you will find. Nobody but drywallers use phillips, and that's because they use specialized bits that take advantage of its willingness to camout in order to dimple but not puncture the paper.

As far as wood screws for things like framing, decking, roofing, siding, etc, I have never encountered any professional who prefers anything besides Robertson. If you are using good quality bits and screws, you can start and drive a 3" #8 deck screw straight down one handed while your other hand grabs another screw from your pouch. Proper Robertson bits are usually colour coded and are always two piece, which allows for a good hardened bit at modest cost. The angle of the taper and the rounded corners on the bit are also essential. You should always be able to take a screw off the bit with a light pull.

I have probably spent more on Torx bits than on Robertson, and seem to wear them out faster, despite not using them nearly as often. They are also more expensive despite being generally softer steel. The screws are hard to find and generally ruinously expensive compared to Robbies.
posted by [expletive deleted] at 12:37 PM on March 22, 2016 [6 favorites]


Robertson is superior when you need the taper to keep a fastener locked up on a bit despite gravity's pull. Torx is superior in all other mechanical ways. It has a much much lower torque angle and a much larger force-bearing surface, so the bits last much, much longer. That is, Robertson's torque angle is between 45 and 90 degrees across its face, so it relies on the corners and shear lock-up to transmit force. Torx bears its force almost entirely along a 15 degree face, so the corners are only important insofar as they extend the face.

As the bits wear (or if they or the recess are made with poor tolerances), the problem gets even worse. Robertson bits lose drive torque as they rapidly fall down the sine curve, concentrating the force entirely on the corners. Torx bits lose it fairly linearly until the faces wear so thin that they can't physically support the force.

A lot of the negative experience with Torx drive is that it's much easier to make a crummy Torx bit, though it's somewhat easier to make a good Torx recess. An accurate shape is easy, but proper material is much more important in a Torx bit than in a Robertson (or square or, to a lesser extent, hex) bit.

Don't get me wrong: I adore and endorse Robertson head fasteners for a lot of my work, but they're a worse solution in terms of usability and durability elsewhere.
posted by introp at 1:14 PM on March 22, 2016 [5 favorites]




Since this is a screw thread: I don't know where we got it, but we once found a vacuum pump of Soviet manufacture in a store room in the lab. Never used, must have been sitting there since some time in the 1960s or '70s. Of course we wanted to start it up, maybe even use it for something that doesn't require the pump to suck too much, so we took the top off to take a look at it and check the oil gaskets. It was held down by six round-headed slot screws which looked identical at a casual glance (and probably were supposed to be identical) that not only required two different screwdrivers to remove but also would not fit back in the threads when mixed up. Apparently Soviet engineering was not very big on screw consistency.
posted by Dr Dracator at 1:26 PM on March 22, 2016 [6 favorites]


Yep, Pozidriv #2 or nothing (as is actually the case for virtually all cross head screws in Europe). If the bit doesn't say PZ2 on it, I ain't screwing with it.
posted by ambrosen at 1:28 PM on March 22, 2016 [1 favorite]


k.5, I've done entire decks—two screws per deck board every sixteen inches—with just one torx bit. If you get good ones they last for a really long time. I actually have never worn one all the way out, but the deck screws I use give you like three bits in every box of screws so eventually I just grab a fresh one even though the old one is still driving fine.
posted by Anticipation Of A New Lover's Arrival, The at 1:41 PM on March 22, 2016 [2 favorites]


PZ2 is definitely where it's at in Europe. PZ1 and PZ3 are not uncommon either. Using the wrong sized Pozi will tend to wreck the head of the screw, but if you remember to check the fit before you start turning, it's not an issue. Even a couple of decades after Pozi screws became the norm, I still encounter people who don't know a Phillips from a Pozi and complain that the screws are too fragile these days. We need public information films or something... and meanwhile B&Q continue to sell bags of overpriced slot-head screws that nobody in their right mind would use for anything, except maybe repairing antiques.

I'd love to move to Torx or hex screws, but they're just not available in the range or at the price of Pozi screws.
posted by pipeski at 2:01 PM on March 22, 2016 [2 favorites]


Hundreds of ruined Ikea screws later, I finally learn about Posidriv®.
posted by cosmic.osmo at 2:19 PM on March 22, 2016 [3 favorites]


Why would you prefer Torx or hex, pipeski? The advantage of Pozidriv is that you get nearly all the positive engagement of Torx or hex, but without any issues getting the driver located in the head. Torx locates itself a little, but with hex, you have to put the bit in exactly the right place, exactly normal to the head of the screw. Much easier with a PZ2.
posted by ambrosen at 2:25 PM on March 22, 2016


I adore and endorse Robertson head fasteners for a lot of my work, but they're a worse solution [than Torx] in terms of usability and durability elsewhere.

I'm with you on the wear issues: any one who has used Robertsons knows that you have to change bits fairly frequently. However, do you really find that centering and engagement is as easy? Torx has always seemed fussier to me. Not as bad as an Allen bolt, but still a little more awkward. The Robertson drive is just as easy to get the bit in the head as a Phillips, but has much more reliable engagement.
posted by bonehead at 2:34 PM on March 22, 2016 [1 favorite]


somewhat related side note: this project has 3d files for many of the super weird drive heads used for advertising bus stop shelters around the world.
http://www.publicadcampaign.com/PublicAccess/Index.html
posted by danjo at 2:42 PM on March 22, 2016 [2 favorites]


There's also these really annoying one way security screws.

(I like PZ2 though)
posted by Just this guy, y'know at 3:16 PM on March 22, 2016 [1 favorite]


Blah blah blah jokes about looking for a good screw blah blah blah.

Anything I need to take apart on a regular basis gets the allen or torx treatment if at all possible. I've spent too many trips to the hardware store, and to Portland Screw (how they secured that URL is beyond me) with a sack of bolts and screws just to say "this but allen or torx." I'll admit I like allen heads because I'm already carrying around a bike-tool with me all the time. Not having to scrounge for the right bit is the besssst.
posted by furnace.heart at 3:23 PM on March 22, 2016 [2 favorites]


Robertson is superior when you need the taper to keep a fastener locked up on a bit despite gravity's pull. Torx is superior in all other mechanical ways.

This is true, but at least as far as my experience goes, the ability to keep a fastener locked up on a bit is so useful that it overwhelms other considerations. That said, I also agree with bonehead that I find Robertson heads easiest to centre and engage.

I'm with you on the wear issues: any one who has used Robertsons knows that you have to change bits fairly frequently.

I find this is mostly a result of poor tolerances. I always have a few garbage bits, and I will chew through them fairly frequently. I also have a few "good" ones that I only use on screws that actually conform properly to the standard, and those I have had for years and years. I have one specific #2 bit that I have had for over a decade and must have driven many thousands of screws and still works like new.
posted by [expletive deleted] at 3:26 PM on March 22, 2016 [2 favorites]


I should clarify that I never buy poor quality Robertson bits, but I just always seem to end up with a plentiful supply of them. I only ever use them for driving damaged or poor quality screws.
posted by [expletive deleted] at 3:34 PM on March 22, 2016 [1 favorite]


The only excuse for using slotted screws is when they're exposed on a black iron hinge and you get them perfectly, exquisitely clocked.

All else: Team Robertson, baby. The USians can blame Henry Ford's avarice for their lack of this marvellous invention.
posted by Mary Ellen Carter at 3:58 PM on March 22, 2016 [2 favorites]


I would have titled this post "More News About Screws Than Youse Could Possibly Use".
posted by barnacles at 4:17 PM on March 22, 2016 [10 favorites]


There are bits, and there are drivers. Bits are almost always worse quality, simply because they're trivial to replace. A well made driver, using properly hardened and tempered steel, will never fail unless you use it for anything but installing/removing that style screw.

Using a well made driver is a pleasure, even with bits like the Phillips.

Most drivers are crap. If you paid two bucks for it, it's almost certainly crap.

There are also crap screws. Nothing to be done about those except toss them. Note that there are limits to any fastener, and they fail if you exceed them. If you need to handle high loads, you need spec fasteners. I know a race team that had a strict policy on having anything weaker than SAE Grade 8 on hand and those were never to be used on the race car.

It all depends on usage. Some need to be tough. Some need to be strong. Finish fasteners need to look good after installation.

It is not a simple subject.
posted by eriko at 4:19 PM on March 22, 2016 [3 favorites]


From the article:

Theft Proof fasteners are virtually impossible to remove without the matching driver

I don't know why they even bother making non-countersunk versions of these, but I see them all over the place. It makes me want to carry vise grips around with me just to steal poorly-thought-out anti-theft screws.
posted by aubilenon at 4:23 PM on March 22, 2016 [3 favorites]


Imagine needing to screw in a Pozidriv but only having a Sel-o-fit to hand. Whoo, boy.
posted by turbid dahlia at 4:44 PM on March 22, 2016 [1 favorite]


Came in searching for Reed & Prince thanks MikeMC. Hard to understand how an article on cross-head screw designs could miss it. It's what you always wanted a Phillips to be- cross head with no camout. They were the greatest until Robertson came along.
posted by Mei's lost sandal at 5:03 PM on March 22, 2016


aubilenon: "I don't know why they even bother making non-countersunk versions of these,"

Because you are often wanting to fasten thin sheet metal to other things. And a cap screw with a large slope to the head will be proof against pliers (though you don't see that very often).
posted by Mitheral at 5:05 PM on March 22, 2016


Reed & Prince is right there, in step #9.
posted by zsazsa at 5:26 PM on March 22, 2016


Of course the best security screw doesn't look like a screw at all.
posted by Mitheral at 5:33 PM on March 22, 2016 [12 favorites]


I sat down at the computer to buy a screwdriver & then wandered over to Metafilter and, bam! it's a screw thread!
posted by mr vino at 6:40 PM on March 22, 2016 [2 favorites]


Hex heads + ball drivers, so you can get at them from an angle. Good for really big things; torx probably wins at the very small end.
posted by kiltedtaco at 7:24 PM on March 22, 2016 [1 favorite]


I love squarehead screws more than Al Swearingen in a Swedish bordello.
posted by NumberSix at 7:32 PM on March 22, 2016 [2 favorites]


I'm pretty happy with Philips or Posidrive for most screwing applications, and I appreciate that you can use the wrong bit in a pinch. It would be nice if there was better international standardization.

But bolting-- can we just all agree to burn Torx to the ground? Unless you're working on super-fiddly small stuff, and sometimes even then, hex heads are fantastic. It's super standard, everything just works, and you can improvise your own drivers in a pinch. Did you chew up the end of your hex key? Go ahead and just grind it down a millimeter or two. Like new.
posted by phooky at 7:46 AM on March 23, 2016 [2 favorites]


phooky: I think this argument really divides us all on the question: "Which is more important to preserve? The tool, or the part?"

Phillips, for example, tries to defer to the part, although it fails spectacularly because a damaged tool will damage the part; Torx absolutely defers to the part, with the tool failing before destroying the screw.

Hex heads and Robertson round out the hole in the part when used with a damaged or incorrectly sized tool, and 'you can regrind a tool'.. deferring more toward preservation of a tool over a part. Blade heads; always the tool. (let's not get into the argument of hollow ground blade heads vs wedge heads)
posted by Xyanthilous P. Harrierstick at 9:24 AM on March 23, 2016


But bolting-- can we just all agree to burn Torx to the ground? Unless you're working on super-fiddly small stuff, and sometimes even then, hex heads are fantastic.

When hex keys get small -- smaller than 4mm or 3/16" -- they have very little bearing surface, and any wear basically rounds them out and they can't torque. You can mitigate this with a very deep socket on the fastener, but that costs you material, and countersinking it becomes hard. Torx is much better here because of the splines -- you wear the tip of the splines and there's still plenty of surface able to torque the fastener. On larger screws, the hex head generally supply enough torque without damaging the screw or the driver, so going with the much simpler hex head is good.

My rule of thumb is that T25 and below are all useful sizes. The standard says you'd use a T25 on an M5 or #12 flat head screw. T27 is 5mm, so at that point, hex is the way to go. There are oddball applications where you need very high torque, if Torx can't do the job, you have to go to something explicitly designed for very high torque applications, like Torq-set or Polydrive. You see Polydrive often in auto applications in brakes and driveshafts. Torq-set is popular in aviation.


Did you chew up the end of your hex key? Go ahead and just grind it down a millimeter or two. Like new.

Unless you heated the metal too much while grinding it, in which case, you've just annealed that metal to dead soft, and that tool is going to wear out like mad. It's fairly easy to then temper the steel to dead hard, but that means it's going to be brittle. Tempering to a mid point is much harder unless you know exactly what metal the tool is made of so you can get it to just the temperature you need for the hardness you want.

If you grind slowly and carefully, constantly cooling the tool and never letting it get over 120F/48C, then you won't change the temper.

It does work -- but you have to do it slowly and carefully.

Then again, if you keep chewing up the end, maybe the steel wasn't hard enough to begin with -- though a general rule for screwdrivers is that if they're harder than the fastener, they'll damage the fastener, if they're softer, the fastener will damage the screwdriver. Which is right? Well, that depends!
posted by eriko at 9:58 AM on March 23, 2016 [2 favorites]


I use a butter knife for about 60% of those shapes. I'm not proud of it.
posted by ShakeyJake at 10:15 AM on March 23, 2016 [5 favorites]


As a copier/printer guy, I run into a lot of JIS screws. It's getting harder to find JIS drivers, but not at all impossible if you are willing to import. Copier companies like Katun and Densi-Seldrum used to sell packs of JIS bits, but a lot of that has dropped off. I still have a handful of pristine Ames green handle #2 JIS drivers still in the packaging, that I carefully ration out as my current drivers wear down.

You can sort of get away with filing the tip down on a regular #2 Philips, and the ACR drivers help some, but nothing feels or fits quite the same as a true JIS bit in a JIS screw.
posted by xedrik at 12:22 PM on March 23, 2016


Ugh, cheap Torx drivers are terrrrrible. But with a good driver, you get all the advantages of Robertson in terms of gripping the screw for a one handed insertion, but it can handle more torque. However, finding Robertson head screws is much, much easier than Torx if you're stuck with whatever they happen to have at Lowe's Depot. That is why my pinball machine's body is an all Robertson assembly, aside from a few things, like the bolts for the legs, which are hex head. The TVs have some sort of cross head holding the logic boards to their respective frames, but that doesn't count since they came that way from the manufacturer.

I'll tell you what grinds my gears, though. "Normal" sized PCs that use round headed Philips screws. PC fasteners should always have a hex head, as God intended! (Except when it is physically impossible, of course) I don't mind if they have a cross, slot, or bith also but I should be able to pop the bit out of the small end of a 4-in-1 screwdriver and drive the damn things.
posted by wierdo at 9:10 PM on March 23, 2016


Hundreds of ruined Ikea screws later, I finally learn about Posidriv®.

I feel like IKEA should mention this somewhere. Surely???

But then they do make their cam lock things out of some sort of especially shatterable lightly-compressed-metal dust or something, they clearly hate their customers.
posted by Jon Mitchell at 5:23 PM on March 24, 2016 [2 favorites]


I feel like IKEA should mention this somewhere. Surely???

In fact, their instructions clearly depict a Phillips driver, and not a Pozidriv driver.
posted by aubilenon at 1:01 PM on March 25, 2016 [4 favorites]


Commenters at this link suspect an IKEA conspiracy
posted by Tandem Affinity at 7:22 PM on March 27, 2016 [1 favorite]


I feel like IKEA should mention this somewhere. Surely???

In fact, their instructions clearly depict a Phillips driver, and not a Pozidriv driver.
posted by aubilenon at 1:01 PM on March 25 [3 favorites +] [!]


Commenters at this link suspect an IKEA conspiracy


Must be a conspiracy...
posted by Martinvermeer at 2:00 PM on April 1, 2016


Slot screws are useful for small brass screws, like on the hinge of a jewellery box or similar. The brass is too soft to handle phillips or something more exotic, and the slot heads look prettier.
posted by bystander at 6:51 PM on April 12, 2016 [2 favorites]


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