Screwdriver heads

[Sockmunkey]

I was reading this thread,
http://boards.straightdope.com/sdmb/showthread.php?t=449989
and it made me wonder.
Just how many different types of screw heads do we *need*? How many exist just for non-technical resons (tamper prevention licensing or trademark issues etc)
How many have physically practical rerasons to exist? (easier for automated manufacturing, less chance of stripping or fouling with corrosion etc)
Could we function well enough if we streamlined to only one or two types so we don't all need buttloads of driver heads? If so, which would be best?

[Booker57]

Just off the top of my head
Flat
Phillips
Torx
Robinson(square)
Posi-Drive
Hex (Allen)

There are sizes for all of these also.

Why do we need all different types? Heck if I know ask an Engineer.

[danceswithcats]

Speaking as a repair person who has had to fix things after some untrained knucklehead got inside and bitched things up, the answer to 'how many do we need' is, apparently: more.

[Sockmunkey]

Speaking as a repair person who has had to fix things after some untrained knucklehead got inside and bitched things up, the answer to 'how many do we need' is, apparently: more.

Yep, crazy people who really want to get into something are going to get in unless it's welded shut.

Sometimes even that didn't stop me. ;)

(I swear that the only things I messed with that I didn't fully understand were disconnected and no longer intended for use)

[ThisSpaceForRent]

Just off the top of my head
Flat
Phillips
Torx
Robinson(square)
Posi-Drive
Hex (Allen)

There are sizes for all of these also.

Why do we need all different types? Heck if I know ask an Engineer.

I add the clutch head screw...but be honest, I know you simply over-looked it... :smack: ...and the Frearson head screw



Screw page (http://www.sizes.com/tools/screw_drive.htm)

tsfr

E/T fix spelling and ...awww nevermind

[Rick]

I was told by a person at the factory that Volvo saved 4 million dollars a year in repairs to new cars when they switched from Phillips to Torx. Torx bits don't skate out of the screw, Phillips do.

[fifty-six]

Just how many different types of screw heads do we *need*?


I don't know, but this company (http://www.tamperproof.com/index.cfm?fuseaction=products) is in the business of making more all the time.

Seems mainly for security.

[ThisSpaceForRent]

I was told by a person at the factory that Volvo saved 4 million dollars a year in repairs to new cars when they switched from Phillips to Torx. Torx bits don't skate out of the screw, Phillips do.

I enjoy finding Torx fasteners cause I have torx up to T40....damn, they go up to t100.

on further research...the spanner, and the Triple square screw(driver)...not to mention Tri-Wing and TorqSet... :smack: :smack: and i take things apart for fun....I've see all of them except the Tri-Wing-Thing... :dubious:

kind regards,

tsfr

[ThisSpaceForRent]

I don't know, but this company (http://www.tamperproof.com/index.cfm?fuseaction=products) is in the business of making more all the time.

Seems mainly for security.

Wow...thanks...I need either a Torx® Pin-Head driver or a Socket Pin-Head driver...thank you for the link..it is saved. ;)

damn...should i have been using Torx® the whole thread?

tsfr

[thelurkinghorror]

Nitpick: Robertson, not Robinson.

[Magiver]

I don't know what it's called but there is an offset "phillips" the military used for titanium screws. It was designed so you could recognize the screw. Next time you look at an SR-71 up close look at the screws.

[Sockmunkey]

Is there any data on which has the best functionalllity?

[Telemark]

Is there any data on which has the best functionalllity?
It depends on what you are trying to do. Each screw head has its own strengths and weaknesses.

[Q.E.D.]

Torx bits don't skate out of the screw, Phillips do.
By design, I might add. Phillips screws were designed to assist mass production by being a) self-centering and b) popping the bit out before overtorquing occurs. Great for one-time rapid assembly; not so great for repeated assembly and disassembly.

[for good measure]

I don't know, but this company (http://www.tamperproof.com/index.cfm?fuseaction=products) is in the business of making more all the time.from that page:
Opsit™ is a reverse thread sheet metal screw that installs counter-clockwise, thus, tightens if removal is attempted.Man, that's so utterly sadistic, I can't believe it.

[Rick]

By design, I might add. Phillips screws were designed to assist mass production by being a) self-centering and b) popping the bit out before overtorquing occurs. Great for one-time rapid assembly; not so great for repeated assembly and disassembly.The problem is when the bit skates out, and damages the paint or interior on a brand new car being built. Then the car has to go offline to be repaired before it can be shipped.
Torx screws with a torque limiting installation tool is a much better solution.

[vison]

I was always told that since the Robertson square screw was Canadian it was a nasty American plot to have the inferior Phillips screw be the "default" as American screw makers resisted a Canadian product.

I guess I was told wrong.

Dang. Maybe Americans aren't evil, even when they're screwing you.

[Sockmunkey]

Man, that's so utterly sadistic, I can't believe it.
Agreed. I actually felt personally offended. :eek:
I'm glad I started this thread, it's been fun and educational. :)

[Rick]

from that page:
Man, that's so utterly sadistic, I can't believe it.
Truly sadistic would be use these in every other hole. :D

[Princhester]

Speaking as a repair person who has had to fix things after some untrained knucklehead got inside and bitched things up, the answer to 'how many do we need' is, apparently: more.

Speaking as an untrained knucklehead who can usually fix things if I can get in to do so, and who often has more trouble getting in to fix than in fixing, the answer to "how many do we need" is, apparently: undecided. Unless you have statistics that show whether there is a net gain or loss to society due to amateur repair, which I'm guessing you don't. And your experience is of course limited to instances of people not being able to repair their own stuff, since otherwise they don't bring it to you.

[Princhester]

I was always told that since the Robertson square screw was Canadian it was a nasty American plot to have the inferior Phillips screw be the "default" as American screw makers resisted a Canadian product.

According to this site (http://www.sachys-robertson.com.au/body_screw_history.html) it was Robertson's refusal to licence his design out that caused it to fail to grab the market.

And while I agree with Telemark that there is no "best" screw drive system, I don't think there are any valid good points for phillips beyond market penetration and therefore availability. Phillips basically does nothing that robertson, or pozidrive, or several others don't do and do better, except cam out ie pop out and round off. And that's only an advantage if one is using a machine that will apply consistent inward pressure such that it cams out at appropriate torque (no more, no less). Yet if you are using a machine that sophisticated then you may as well use one that has a proper clutch, so no real advantage there.

And as for your basic slot screw drive, apart from ease of manufacture (how important is that these days) it's a complete dog and not fit for use anywhere, for any reason. IMHO, of course.

Princhester (who has a workshop full of effin' phillips head screws he's slowly replacing with robertsons as he runs down his old supplies).

[Fir na tine]

Princhester (who has a workshop full of effin' phillips head screws he's slowly replacing with robertsons as he runs down his old supplies).

After I first found Robertsons about 2 years ago, I threw away all of my "effin' phillips head screws" and have never regretted it. For ease of use and holding power, nothing beats Robertson.

[masterofnone]

I've got a generator with inverse Torx studs holding the carb on it. Because everyone has an inverse torx set laying around. :rolleyes:

I had to get a T-25 Torx screw and set it into a handle with epoxy to get them out.

[Ají de Gallina]

Maybe the other screwheads are "better" in some sense, but for me the great advantage of flat or Phillips is that you can use a variety of drivers without needing a specific size for each head.
In my house, with a small and a medium size driver for each a can work all the screws around.

OTOH, my bass has three different-sized allen heads and I need three different allen screws.
Flat and Phillips RULE!!!

[awldune]

I've got a generator with inverse Torx studs holding the carb on it. Because everyone has an inverse torx set laying around. :rolleyes:

"External Torx" socket sets are not impossible to find. I know Sears and Autozone stock them. It does appear that nobody on earth carries individual sockets, so you have to buy a set when you really only need one.

[gotpasswords]

I've got a generator with inverse Torx studs holding the carb on it. Because everyone has an inverse torx set laying around. :rolleyes:

I had to get a T-25 Torx screw and set it into a handle with epoxy to get them out.
And you them promptly threw them away and re-assembled the carb with something normal like hex-head cap screws, right?
Maybe the other screwheads are "better" in some sense, but for me the great advantage of flat or Phillips is that you can use a variety of drivers without needing a specific size for each head.
Sure, same way you can use a screwdriver as a prybar or chisel. It may ultimately work, but something's getting damaged each time around - either the screw heads are getting chewed up, and eventually no driver will work with them, or the screwdriver tips are getting worn down, and eventually they'll be useful only as a screw-ruiner.

Another screwhead not mentioned here yet is the JIS, or Japanese Industrial Standard. It's a variant on Phillips, but shallower. They're usually good enough to be marked with a dimple on the head. A normal Phillips driver is too pointy and won't make good contact. Solution for this is to grind a bit off the tip of a Phillips driver and cross your fingers, or find proper JIS drivers. Good luck finding them at Home Depot or Sears - oddly enough, your best chances are at a shop that caters to radio control airplane and helicopter hobbyists. Apparently RC airplanes are universally held together with JIS screws.

[Tully Mars]

And you them promptly threw them away and re-assembled the carb with something normal like hex-head cap screws, right?

That's what I've been doing on my motorcycle, gradually.

[masterofnone]

And you them promptly threw them away and re-assembled the carb with something normal like hex-head cap screws, right?

I would have if they were normal screws, but they were long studs, and I had alreay made the tool to remove them anyway.

I looked all over town for a set of tools, but all I got were weird looks from people who had never seen them before.

[GargoyleWB]

from that page:
Man, that's so utterly sadistic, I can't believe it.

Yes, apparantly bicycle pedal/crank manufacturers are part of this loathsome bunch. Why the reverse threading of one side? If the thing is designed and torqued properly in the first place there is no need, just lazy manufacture (combined with the aforementioned sadism).

[Gorsnak]

Yes, apparantly bicycle pedal/crank manufacturers are part of this loathsome bunch. Why the reverse threading of one side? If the thing is designed and torqued properly in the first place there is no need, just lazy manufacture (combined with the aforementioned sadism).
Left pedals screw into the cranks with left-handed thread because the ordinary rotation of the pedal will eventually work the pedal loose and spin it out. There may be some amount of torque that would prevent that process from starting, but manufacturers have no way of insuring that that amount of torque is applied, and wouldn't be interested in the liability lawsuits or just the constant complaints of pedals coming loose. It would be bad design to just use right-handed thread on both sides. You could go to something like a square shaft on the pedal going through the crank with a right-hand thread nut securing it on the back side, but now you have an extra part and a more complex system. The existing system is actually a nice design.

[Princhester]

Maybe the other screwheads are "better" in some sense, but for me the great advantage of flat or Phillips is that you can use a variety of drivers without needing a specific size for each head.
In my house, with a small and a medium size driver for each a can work all the screws around.

OTOH, my bass has three different-sized allen heads and I need three different allen screws.
Flat and Phillips RULE!!!

Which is just an indication you don't do much mechanical work. There is no way I could get away with just two screwdrivers for the variation in size between the smallest and largest screws I use. Besides which, three robertson drivers will cover everything from 4G to 14G, and do so properly without damaging anything.

[Ají de Gallina]

Which is just an indication you don't do much mechanical work. There is no way I could get away with just two screwdrivers for the variation in size between the smallest and largest screws I use. Besides which, three robertson drivers will cover everything from 4G to 14G, and do so properly without damaging anything.

of course...it's for the house, a knob, hinges, small stuff; that's the context.
So please, don't change them, do what you want with carburetor.

[mks57]

I don't know what it's called but there is an offset "phillips" the military used for titanium screws. It was designed so you could recognize the screw. Next time you look at an SR-71 up close look at the screws.

That's a Torq-Set fastener. The Army uses a lot of them on tactical equipment. I liked them much more than conventional fasteners. They are probably too expensive for price-sensitive hardware.

http://www.phillips-screw.com/aero_acr_torqset.htm

[Princhester]

of course...it's for the house, a knob, hinges, small stuff; that's the context.

I'm guessing you don't do much of that either. You can turn a screw from your front door hinge, and a screw on a small household appliance, and everything in between with two screwdrivers? No way. Not without doing damage like gotpasswords says, and probably not even then. Indeed, if everything did use a robertson head, you would be better able to use a small range of sizes, because a robertson can transmit so much more force with a smaller bit size.

[Magiver]

That's a Torq-Set fastener. The Army uses a lot of them on tactical equipment. I liked them much more than conventional fasteners. They are probably too expensive for price-sensitive hardware.

http://www.phillips-screw.com/aero_acr_torqset.htm That be the one.

[Unintentionally Blank]

I love Robertson's screws, and need to buy more. To answer 'what are regular head screws good for'...well, I can make em in my home shop. The other kinds? Not so much.

[ntcrawler]

Speaking as a repair person who has had to fix things after some untrained knucklehead got inside and bitched things up, the answer to 'how many do we need' is, apparently: more.

From personal experience the Robertson has advantages when it comes to preventing your driver from slipping out of the screw, and for the screw to stay on your driver when inserting it into difficult spots. I like to use them especially for woodworking and moulding work (been known to wear out quite a few phillips heads).

As to how many we need? I can only reply with a favorite engineering quote of mine: "The Nice thing about standards is that there are so many to choose from!" :D

[Sockmunkey]

The only thing good about the flat ones is that in an emergency you can improvise with other things if you don't have a screwdriver.
Butter knives, dimes, etc.

[Kevbo]

Yes, apparantly bicycle pedal/crank manufacturers are part of this loathsome bunch. Why the reverse threading of one side? If the thing is designed and torqued properly in the first place there is no need, just lazy manufacture (combined with the aforementioned sadism).

Nope, not without thread-locking compound, at least in alloy cranks. They will precess and loosen. (bearing drag is not the issue and will actually loosen them as threaded) This is occasionally tested by folks who try to use solo crank sets on a tandem by swapping cranks side-to-side. The trick of left hand threading the left hand side originated around the turn of the last century, with two brothers in Dayton, OH, quite famous bicycle mechanics who also dabbled in aviation. <googles>...ah yes, Wright was their last name, Wilbur and Orville. Prior to thier innovation the left pedal loosening and falling off was a common problem.

[bouv]

The only thing good about the flat ones is that in an emergency you can improvise with other things if you don't have a screwdriver.
Butter knives, dimes, etc.

And if you stripped the screw head badly on a phillips, then you can Dremel it into a slotted screw and remove it.

[Malacandra]

This has been an interesting thread. I found myself looking at the flats on stage at last night's panto rehearsal and nodding sagely. "Ah... someone's been and turned a pozi screw with a Philips driver, and now look at it..." :D

[Radegast]

This has been an interesting thread. I found myself looking at the flats on stage at last night's panto rehearsal and nodding sagely. "Ah... someone's been and turned a pozi screw with a Philips driver, and now look at it..." :D

When I built sets for a theatre company, we always used Roberston screws. They worked much better with power drivers than other types of screws, and made for very quick and problemless take-down when we did change-overs.