It took me a while (read decades!) to realise that was the reason I continually mangled Japanese cross headed screws and had to replace them with allen headed versions.

The Phillips / Posidrive etc screwdrivers that most diy mechanics (in my UK experience anyway) tend to use are a poor fit in Japanese screws heads and are almost designed to slip out and damage the corners in the process.

Proper Japanese Industrial Std cross headed bits are a "revelation" and don't slip out as easily (on the few occasions I've used them anyway) but you have to go out of your way to find them here. You'd think after 50yrs of riding (and spannering) Japanese bikes I'd have a drawer full of them and use nothing else but I don't. What I do have is loads of allen screws!

If time weighs heavy on your hands here's a link to a discussion about screw heads - JIS Screwdrivers - webBikeWorld

Because stainless will resist corrosion a lot longer than mild steel or zinc plated...

For almost negligible cost...

I can't agree more with this. Ill-fitting tools on screws will do more damage than anything else. Especially if they're corroded in there.

I imagine not even Honda Mechanics own a set of JIS (Japanese industrial standard) though because they're so close to Philips most people don't bother. And to be honest, I bet no ones even heard of them.

JIS screwdrivers are made by a company called VESSEL. They're also really expensive. I have a set of three for really tricky screws but again, I hardly bother.


It's only half the story though.

Everyone owns a set of allen keys. Not everyone owns (or even cares about) a set of specialist screw-drivers.

Allen heads are a safer bet because they're less likely to be bodged by careless owners. And a Cap head allen bolt is far easier to remove when it has been bodged than a cross-head.


It's generally always easier to swap everything with Stainless Allen Cap heads if you can..

Stainless steel is brittle. Don't use it for screws "exposed" to higher loads.