Socket Head Capscrews vs Phillips

[knotzilla]

Sorry about the blurp I started on robertson screws. I saw a program on the inventor of the screw a ways back and I blame it on getting older for a lack of memory for the misinformation. Thanks Ted

[tfb]

So are there any budding metalurgists on the forum, who can tell us a bit about the reactivity between stainless steel and aluminium? Is it practically a non-issue, or should we take a bit of caution and smear a bit of thread anti-seize compound on things just to be safe?

Mike.

[mhardig]

I don't know about motorcycles-yet

but the Land Rover people always used anti-seize and then rubber/plastic washers wherever they could.

Here's a link to a great article on galvanic (dielectric) corrosion of metals, and how it works. Basically, two dissimilar metals form an anode and a cathode, and the anode corrodes. A galvanic chart of metals is available here.

Whichever metal is closer to the anodic end will corrode, and the metal closer to the cathodic end is protected. This is why oceangoing ships often have huge blocks of zinc attached below the waterline, the zinc corrodes and the steel doesn't. I figure I'll use the passivated stainless with a liberal application of (no copper) never seize (I'm told copper (cop-graf) is best for cast iron and steel but never aluminum) and back the screws out every now and then to make sure all is ok. The marine guys, incidentally, use a special Aluminum anti-seize

[mixongw]

It is definitely the best screw for Canadians, since it was invented by a Canadian. As for the rest of the world, "best" would depend on the application.:-D



The Robertson screw was invented in 1908. The Ford Motor Company was one of Robertson's first customers. The Model T Ford used over 700 Robertson screws. The Phillips screw was named for Henry Phillips, who bought the concept from an inventor named J.P. Thompson and developed the screw into a workable form. He founded the Phillips screw company in 1933 but never manufactured the screw. Other screw manufacturers told him the screw was impossible to make, but he finally got American Screw Company's President ( who refused to consider the Phillips head was "impossible" to make) behind the project. After perfecting the process, American Screw licensed it to other manufacturers.

The design purpose of the Phillips screw was to prevent overtightening of the screw. When enough torque was applied, the screwdriver would "cam-out" by design. This had manufacturing advantages over a slotted head screw, as more torque could be applied to the Phillips without the danger of the driver slipping out and marring a finish. It could also be used with automated tools and was self-centering. By 1940 it was used by all automobile manufacturers.

Ironically, the automatic "cam-out" which is useful in manufacturing is the very feature that is disliked by many home mechanics. While more efficient for automated assembly, Phillips screws do not have the ease of positive removal like socket head screws when covers need to be removed for engine servicing.

Isn't cut-and-paste a wonderful feature?

[Boondocks]

Isn't cut-and-paste a wonderful feature?

I am not sure what this is supposed to mean and what point you are trying to make.

I did not cut-and-paste in my reply to mhardig. I read three articles, reviewed and edited the points I wanted to make, and expressed them in my own words. This is called "research" and "writing".

[DaveDanger]

I discovered the softness of Japanese Phillips head screws immediately after riding my 73 CL-350 over (and somewhat THROUGH) a low concrete abuttment wall leading into a one lane bridge somewhere in northwest Kentucky. The impact shattered the clutch cover and painted the entire right side of me with well-used and HOT oil from the previously high-RPM centrifugal oil filter hidden inside the aforementioned cover. A friend located and shipped me a used replacement side cover to help return my ride to a useful form of transportation. I spent 3 days in a stranger's tobacco-barn trying to remove the incredibly useless (I had NO idea that lead could be alloyed with coal-mine debris to create a threaded fastener!) screws and remains of screws from the case. At any rate, I managed to get all but one of the screws cleaned out and replaced with original hardware long enough to get back home. I then invested in a collection of allen-head capscrews for every place on that bike I could get to.
I now loudly and longly proclaim the superiority of allen-headed capscrews and the judicious use of copper-based anti-seize on any motorcycle hardware. "Originality" can bite the big one.
To take this one step further, I'll happily take phillips head screws of any metallic composition over common head screws. All common screws in existence should be smelted down into one solid lump and boosted into a ballistic trajectory resulting in a solar impact. I'll pay NASA's freight bill to accomplish that.

[Boondocks]

Phillips head screws have long been a general PIA on motorcycles, and not just Japanese bikes (in my experience). An impact driver is required to reliably remove these screws. Perhaps the manufacturers should include impact drivers with the toolkit as standard equipment.

Speaking of "soft" Phillips screws, the British bikes of the '50s were just as bad. It was common practice even then for a rider to replace the Phillips screws on covers with Allen wrench socket head cap screws.

[bucketsofgs1000]

Polishing covers

The yellowing on your covers could be alodine, which is a treatment applied to aluminum to make paint properly adhere. But, if you want to polish your covers up again, get rid of the yellow (fine steel wool or wet sanding), and then polish. I have used Eagle 1 billet aluminum polish with much success. Hope that helps a bit,

-Zack

[tfb]

A galvanic chart of metals is available here.

Now that's a very useful chart! It explains very clearly why our brass jets chemically WELD themselves into the cast aluminium bodies of the carburettors, given enough time.

Mike.

[mixongw]

I am not sure what this is supposed to mean and what point you are trying to make.

I did not cut-and-paste in my reply to mhardig. I read three articles, reviewed and edited the points I wanted to make, and expressed them in my own words. This is called "research" and "writing".

I'm sorry if I offended you. I am writing a paper on fasteners and was able to use some of your text. I should have been more verbose in my comment.

[Boondocks]

I'm sorry if I offended you. I am writing a paper on fasteners and was able to use some of your text. I should have been more verbose in my comment.

Aha! So you're the cut-and-paster. I didn't have time to copyright my text, so I suppose it is fair game.

No offense taken. I just wasn't clear on your comment without the context. I'm glad to have been of some help with your paper. Thanks for the feedback.