General Cycling Discussion - Why Allen/Hex type screws?

Just wondering why is this format used over the regular philips type screws for bike components? Any thoughts?

More durable. Less likely to slip. Allows use of torque wrenches. Allows easy one hand starting with a straight allen wrench.

Allen/hex head fasteners are very common in most equipment. My most used tool was a 2.5 mm hex wrench when I worked in the semiconductor industry.

More durable. Less likely to slip. Allows use of torque wrenches. Allows easy one hand starting with a straight allen wrench.


+2 :thumb: Exactly.

Philips head fasteners are too easy to damage the slot on and, as noted, hard to get to use with a torque wrench. Another alternative is Torx head fasteners which are used on the Rohloff gear hub and on some other bicycle components. IMO harder to find than hex socket head fasteners and more expensive.

More durable. Less likely to slip. Allows use of torque wrenches. Allows easy one hand starting with a straight allen wrench.

Allen/hex head fasteners are very common in most equipment. My most used tool was a 2.5 mm hex wrench when I worked in the semiconductor industry.

If that is the case, why not use Allen/hex for every screw type? Also what's with the SAE vs. Metric? Why not just conform everything into one std?

Because the tool makers would lose money!! I say 2 thousand and late. ;)

If that is the case, why not use Allen/hex for every screw type? Also what's with the SAE vs. Metric? Why not just conform everything into one std?

Some industries do use Hex head almost exclusively, bicycles for one. Philips and straight slotted head fasteners are easier to make and thus available cheaper, a consideration in many applications. Particularly so if the fastener is not intended to ever be removed after it is installed. like wood screws.

Bikes are almost exclusively Metric as are virtually all currently sold cars. SAE fasteners are still used due to some domestic manufacturers refusal to change and will always be needed for replacement and repairs on existing equipment. The USA is the only holdout against ISO Metric fasteners and the whole Metric system. This is due to Congress chickening out on the metric conversion program they originally legislated for 30 years or so ago and then reversed themselves on.:rolleyes:

BTW hex socket head fasteners are not ideal either as at least in the smaller sizes the wrenches can round off and then do the same to the socket head in the fastener. Torx is better in that respect.

Bikes are almost exclusively Metric as are virtually all currently sold cars.
Except for things like pedal threads (1/2" and 9/16" and pitch also in tpi), bottom bracket threads of 1.37" x 24 tpi (although a width of 68mm), 1" and 1 1/8" headsets, and 1" diameter handlebars. It's still a mishmash of metric vs. British units.

Ironically for the items above there used to be readily available metric versions as well - the old French standards, but those have disappeared and now one needs to get these with British measurements rather than metric.

Really, wunderkind? I've always thought Phillips head screws should be banned from industry. They not only slip, they are designed to slip. Something about rounding out the head being better than scratching the delicate finish of whatever they fasten.

I think the only place on my bikes where there are Philips-heads are the set-screws on my derailleurs.

If that is the case, why not use Allen/hex for every screw type? Also what's with the SAE vs. Metric? Why not just conform everything into one std?

If you want, you can replace all or most of the hex head screws on your bike with Phillips. For any odd sizes, check out BoltDepot.com.
Report back on how it turns out.

The vast majority of equipment I've worked on in the last 15 years is ISO, no matter country of origin. True, somethings are still SAE, but really no big deal. The US did not chicken out on going metric. The market has decided. Metric for some things, English for others. Again, no big deal.

I have no trouble going between gallon/liter, inch/meter, gram (of force)/pound. or Fahrenheit/Celsius. Just about any industrial tech worth their salt does it everyday.

BTW, even though my name is Phillip, I have always hated Phillips head fasteners. What a royal pain.

Torque wrenches, pure and simple. Can't get a good torque setting with phillips heads.

If that is the case, why not use Allen/hex for every screw type? Also what's with the SAE vs. Metric? Why not just conform everything into one std?

'Cause we're 'Murkans.
We can't adopt a standard if those Furriners are using it!:mad:

Why should we adopt a "standard"? We don't have a "standard" for language or religion. Why have one for measurement? Use what ever works for you.

If you're manufacturing something, then you're going to use fasteners that are easiest and best for you when making it, not for the customer when working on it.

I'm sure glad my crank bolts aren't phillips head. I'm also glad they're typically allen head and not ye olde style "hex head bolt" any more.

I have no trouble going between gallon/liter, inch/meter, gram (of force)/pound. or Fahrenheit/Celsius. Just about any industrial tech worth their salt does it everyday.


You don't work for NASA then. :D



http://www.cnn.com/TECH/space/9909/30/mars.metric/

Phillips head fasteners just need to be put in the dustbin of history, pure and simple. Even Allen head screws tend to slip or cam out after being used often. It would be nice to see a wholesale move to Torx, Torx Plus, or a modern screw head that is resistant to camming out, transmits maximum torque, and can handle a large number of uses.

I still don't mind phillips for set screws. Since those smaller sized allen heads are very easy to strip. I got a great deal on some Avid brake levers for $2, but one of the reach adjustment set screws is stripped out. It's allen presumably because it's so hard to get a normal phillips head in between it and the handlebar. I'll be replacing it with phillips, however since I have a 90 degree phillips driver.

Phillips head fasteners just need to be put in the dustbin of history, pure and simple. Even Allen head screws tend to slip or cam out after being used often. It would be nice to see a wholesale move to Torx, Torx Plus, or a modern screw head that is resistant to camming out, transmits maximum torque, and can handle a large number of uses.

This is interesting:

"Where Phillips heads were designed to cause the driver to cam out, to prevent over-tightening, TORX heads were designed to prevent it."

Ref: http://en.wikipedia.org/wiki/Torx


Well, I must say the Phillips design has been a smashing success.:mad:

You don't work for NASA then. :D


No, but in the late '70's I worked for a company that sized some equipment without converting Fahrenheit to Celsius. I was involved in start-up of the new plant. About 3 AM on the first day of trials we had a pressure spike in a drier. Fortunately the explosion suppression system worked otherwise I wouldn't be here. The plant never opened.

This is interesting:

"Where Phillips heads were designed to cause the driver to cam out, to prevent over-tightening, TORX heads were designed to prevent it."

Ref: http://en.wikipedia.org/wiki/Torx


Well, I must say the Phillips design has been a smashing success.:mad:

A friend of mine learned the hard way about using deck screws with Phillips heads versus Robertson (square) head screws. Though Robertson screws don't have the effeciency that Torx do, they are a lot better than Phillips heads. Your hands get a lot more tired trying to drive in Philips deck screws in and hope they don't cam out before the screw is completely in place as opposed to a Robertson head which will happily keep going until the screwdriver's chuck recognizes that it is at its max torque setting.

I do know one good use for the Phillips design -- tamper resistance. I screw one in, and if I interchange bits with a Pozidriv, it rounds out in a hurry making it impossible to extract without power tools.

it's different because you'll never get EVERYONE to agree on one set of standards. if you don't like what you have, replace your fasteners. If you can't find a matching size, redrill and tap your holes, then replace them. OR, you can deal with it, accept the fact that it's never going to standardize, and move on. I can adjust every fastener on my bike with 4 tools: that's crazy. I'm a locksmith by trade, and I can't think of many pieces of hardware that adjust with only 4 tools... different types of screws/bolts/whatever need different types of drives. manfuacturer's go with the cheapest they can, and since your bike probably wasn't built stem-to-stern by the same company, they'll all have different suppliers of their 'cheapest' fasteners.