According to this site 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).
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.
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!!!
“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.
And you them promptly threw them away and re-assembled the carb with something normal like hex-head cap screws, right?
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.
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.
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.
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.
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.
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.
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!”
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.
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.
