Another reason I thought of all this has to do with my having to remove some hinges and latches from some old cabinet doors - these doors had about upteen coats of paint on them so it was quite a task - it was also away from my shop so I was wishing I had a brace with me. Why a brace? One sort of forgotten advantage of the brace is for the amount of torque that can be applied to a slotted screw using a flat-tip screw brace bit. Using a large brace (12" swing), plus with the amount of pressure you can exert on the pad, you can worry off just about any slotted screw - which is what these old hinges had under all the paint. As it was I managed to remove them all but it took much more time than it normally would have had a brace and flat-tip bit been involved.
So last night the thoughts of the day ran through my head and I started thinking about drivers and screws - this naturally (at least for me) got me thinking about different types of screw head-types and what I knew about the flat tip, Phillips and square drive. So this is what I knew (through anecdote, discussion, etc):
- The square drive and screw was actually patented by a Canadian named Robertson – thus it’s called the Robertson drive in Canada and it’s ubiquitous in use north of our borders – this drive actually pre-dates the Phillips drive and screw in the US.
- The Phillips drive and screw was invented by someone in the US who sold the rights to a company who marketed it under the Phillips name. Initially there wasn’t a good way to manufacture the screw heard (and there are variations with up to 6 or 8 vanes/slots) so the patent pre-dates the actual manufacture by some years. I had also heard that the Phillips bit was developed for the manufacture of airplanes (something to do with the attachment of the aluminum skin – the recessed head discouraged drag and the shape of the slots allowed for the head to “cam out” rather than the screw being over-torqued and the threads being stripped).
- According to what I’ve heard, the Phillips screw and drive owes its use in the US to Henry Ford, who wanted to use a product in his vehicles that was patented and owned by a US company rather than one outside our borders.
- It’s obvious in retrospect that the Phillips drive is inferior to the Robertson’s drive due to the built-in design (the desire to cam out instead of stripping). Strange that it’s used on everything and has pretty much replaced the slotted screw and driver – well it is easier to register and use than a slotted fastener. But why has it taken so long for the Robertson drive to gain popularity among US users? I first saw the Robertson screw being used by outdoor deck builders – makes sense as the drive head doesn’t strip – the worst thing about a stripped head when building decks is that it takes off the coating that prevents rust – once the head starts to go the coating causes rusty spots that are very un-slightly, in a very short time.
Next topic: the Monkey Wrench!