Others were in an attempt to make dis-assembly or tampering more difficult (there is nothing foolproof) but as far as we are concerned with woodworking, there are only a few fasteners (screw types) to be concerned with.
THE SLOT OR COMMON SCREW
The Slot screw is probably the first one that came out.
Since they were mostly hand made by a blacksmith, there was a lot of variations. Both in the thread and in the location and size of the slot. This variety of slot sizes may help explain why the tip of our common or slot screwdriver were flared in two directions: In width and in thickness, in an attempt to accommodate them all.
This of course introduced two major problems:
Depending on the slot width and the thickness of the blade tip taper,
the driver is only engaging near the top of the slot, which means the all too familiar cam out and damaging of the slot walls.
Because there is essentially no registration for the tip to remain centered on the slot, it is also all too easy to slip out and damages the surrounding wood.
If you attempt to sink the screw head below the wood surface, that width taper is going to cause more problems.
The best way to avoid these damages and frustrations is of course to uses a properly fitted screwdriver and screw. The slot has parallel walls, you will have a much better fit if your screwdriver tip had too (no taper) and was sized correctly for the screw slot (in width and thickness)
That is why in woodworking, your best bet are a set of parallel tip screwdrivers.
For some reasons I never understood, these typical English Cabinet maker set of screwdrivers are not cheap, commanding good price on the used market (supply & demand?)
The good news is that you can buy excellent parallel sides screwdrivers from Brownells and etc. Take a look at gunsmith suppliers.
One brand in particular which is now available from some woodworking supplies store are the Grace screwdrivers. I got mine from Lee-Valley.
Well worth the small investment if you are using slot screws for that period correct look. For everything else stick to Robertsons!!
Since being "discovered" by the woodworking community, Grace also now make specialized screwdrivers for handsaws.
Of course we all know that numerous saws makers have been using split slot nuts for eons, and the only way to tighten properly without damages is to use the appropriate split slot screwdriver... Problem is there were no real standard, so you may required a few to handle all your saws.
A much better fit is with using the correct fitting parallel blade screwdriver, available from most saw makers.
But what about the older saws makers such as Disston and all? The good news is that it is easy to make your own properly fitted split nut screwdriver armed with a file. I use a rat tail file to make them. How deep to make the slot? deep enough to clear the saw nut post with some room to spare.
There is nothing more injurious to a saw handle than to continued using it with a loose handle. It will caused the saw nuts hole to widen compounding the problems. That saw handle being made of wood is going to expand and contract with the humidity levels in your shop throughout the seasons. That in turn will cause the handle to loosen in time. Similar problem with wooden totes and handles on a plane.
Another specialized area for slot screwdriver is for handplanes.
If you ever struggle not to slip while tightening or removing the screw holding the blade and back iron (chip breaker etc) you gotta try this clever design from LV . Simply brilliant! It capture the screw head ensuring no slips. NO, it would not fit every plane iron screws out there, but it will for the majority of modern design (think Stanley, Record and etc)
If you are intent on using a cordless screwdriver to fasten or loosen these slot screws (or any screws types for that matter), you better have a good fit between your driver bit and the screw head or you will damaged them in a hurry.
And finally, if using brass screws, it is always very wise to pre-drill and uses a steel screws first to tap in the threads BEFORE driving in your brass screw, or be prepared to cry over (or uses appropriate expletives:-) when you snap the head off.
And remember for everything else, you cannot beat the Robertson...
Incidentally, I have since discovered that the so called Square Drive screws in the USA are NOT true Robertson copies.
Only Robertson and its licensees makes Robertson screws and drivers, the others are generically called Square Drive and are made by several manufacturers and brands since the patents have expired on the Robertson.
The Square Drive is an American clone of the Canadian Robertson that has a square recess but not tapered and has very sharp corners.
Likely this difference was to avoid patent infringements. The patented Robertson driver has slight taper and slightly rounded corners
Correspondingly, there are two similar looking driver bits. The two methods of fabrication are:
The machined one piece and the two pieces, which is a forged steel tip pressed fitted into a steel shaft.
Several companies each with their own select brand names produced Square Drive. ALL true Robertson power bits and insert bits are of the 2 pieces variety, they have NEVER produced the one piece machined bit design.
If your driver says Made in USA it is made to fit Square Drive screws
Of course this now is creating a problem here in Canada, since with the arrival of the giant US retaillers Home Depot and Lowes, they are no doubt introducing these inferiors Square Drives screws and drivers unto an unsuspecting public.
and if you ever work on consumer electronics, you ran into the slightly different Japanese Phillips imitation: JIS B 1012.
BUT if you enjoy cursing and swearing in any language, then go ahead and use the same screwdriver on all these different types :-)
Bob, with a rather large collection of screwdrivers, and now you know why.
Choose your weapons wisely :-)