This bugs me so much more than it should. Why do we have three different standards for + shaped screws? You know what doesn’t have this problem? Flatheads. There’s exactly one way to make a flathead screwdriver, and I won’t be looking it up to make sure I’m right
Their isn’t one way to make a flat head screwdriver. Some a chisel and some are slots. The slotted ones are better but more expensive.
Both still slip from the screw and are a pain to manually screw (slotted less so).
Pozi is the best + type screw. It’s pretty much standard for UK construction. The only time a different type is used is sometimes Phillips for plaster board or external hex and internal torx for long or large screws.
There are at least 3 standards for the + shape already. Phillips, Pozidrive, and Japanese Industrial Standard (JIS). They do not play well together.
insert obligatory xkcd standards reference
This bugs me so much more than it should. Why do we have three different standards for + shaped screws? You know what doesn’t have this problem? Flatheads. There’s exactly one way to make a flathead screwdriver, and I won’t be looking it up to make sure I’m right
Their isn’t one way to make a flat head screwdriver. Some a chisel and some are slots. The slotted ones are better but more expensive.
Both still slip from the screw and are a pain to manually screw (slotted less so).
Pozi is the best + type screw. It’s pretty much standard for UK construction. The only time a different type is used is sometimes Phillips for plaster board or external hex and internal torx for long or large screws.
Should the slot be partial or go all the way through? If partial, is that standard for the size of the screw, or universal?
How wide should the slot be? Should that change based on the size of the screw?
How deep should the slot be?
Should the sides of the slot be perfectly straight, or angled to perfectly fit the wedge shape of the driver? If angled, what angle?
Should the bottom of the slot be perfectly flat or slightly rounded so a coin or something could be used in a pinch? If rounded, what radius?
Should the top of the screw be perfectly flat, or domed, or raised?
Should the bottom of the head be flat, angled (at which angle), smooth, rough.
Should we use metric or freedom units for the thread pitch?
Should the threads go all the way to the head?
Should the point of the screw be flat or tapered (at what angle)?
Ok, only the first half of those were about the driver used, but I’m sure there are things I missed in that!
Don’t forget Frearson/Reed & Prince!
But wait, there’s more!
And even more!
JIS has been obsoleted and replaced in Japanese products with the ISO Phillips bit shape. It still exists on lots of products pre 2000 though.
Kawasaki is still holding on strong to JIS screws in it’s machinery.
Are you sure they’re JIS? Because JIS and ISO are interchangeable and effectively the same; the ISO adopted standard used most of JIS’s rules.
Yeah. I keep one of these around just for older Yamaha and newer Kawasaki equipment. You’ll end up drilling half of them out if you try to use #3 ISO.
I’m in the powersports/agricultural industry, so we tend to lag behind everyone else.
That’s just galvanic corrosion from using cadmium plated bolts in aluminum fuel injection hardware. It’s basically free loctite.
JIS is looking better according to these guys…