Quick Q. re screw heads eg derailleur mech stop screws...

[simonineaston]

Does anybody know which particular bolt head form is used on nearly every Shimano, Suntour, etcetc that I've ever seen? That strange hybrid - a slot head with added extra as if to say, "Well you can use a Phillips or a Pozidrive if you want... but it won't really fit!" Is it maybe a small version of JIS?

[Cugel]

Does anybody know which particular bolt head form is used on nearly every Shimano, Suntour, etcetc that I've ever seen? That strange hybrid - a slot head with added extra as if to say, "Well you can use a Phillips or a Pozidrive if you want... but it won't really fit!" Is it maybe a small version of JIS?

The best fitting screwdrivers for Japanese bicycle bit bolts of that kind is one that's JIS (Japanese Industrial Standard) compliant. JIS bolt heads look like Philips .... and one or two Philips screwdrivers do fit reasonably well, Wera being one example. However, a proper JIS screwdriver of the right size is best, if you can find one.

[rjb]

They are jis screw heads. Using a Philips or pozidrive risks camming out unless the screws are free and not binding and butchering the screw head. You may find a jis screwdriver in a Toyota car tool kit.

[simonineaston]

Thanks, folks, for confirming my suspicion. I rediscovered this particular anxiety when I offered to adjust a work colleague's derailleur-equipped bike last week. As a serial hub gear user, I've been worry-free - at least, in that context for ages!

[tenbikes]

I replace them with SS Allan key bolts. Look nice, no extra tools, no issues in 20 odd years and probably 40 odd bikes!

[fastpedaller]

I replace them with SS Allan key bolts. Look nice, no extra tools, no issues in 20 odd years and probably 40 odd bikes!

You have over 40 bikes! why are you called Tenbikes?

[Sweep]

Aren't JIS screwheads used on V brake arm adjusters as well?

I know I have had no issue with them since I bought a set of JIS screwdrivers.

Had had issues before.

Was pleasantly surprised as I had read some things online which seemed to say that JIS screwheads were a mytth, just the same as Philips in practice.

I got mine from an ebay supplier in kent/south London.

Forget which, may be able to dig out if anyone interested.
>> corrected for typo

[Jdsk]

Do people who do this many times a day deliberately buy JIS screwdrivers? Or do they find a specific screwdriver that works well in practice whatever it's labelled?

Thanks

Jonathan

[Sweep]

Do people who do this many times a day deliberately buy JIS screwdrivers? Or do they find a specific screwdriver that works well in practice whatever it's labelled?

Thanks

Jonathan

Not sure that I understand your post.

You implying that JIS screwdriver are a waste of money?

The ones I bought weren't expensive.

And after a fair amount of **ing/mashing things up I late in life believe in using the correct tool for the job. Avoids issues you can avoid.

I quite often quickly adjust the V brake balances on my many V brake equipped bikes (very much all) including this morning. Takes seconds. Positive dependable seconds.

[rjb]

Couple of pics highlighting the difference between jis and Phillips and shows how a Philips is not a good fit in a jis head. I think the dot on the jis screw head identifies it as such.

[Bmblbzzz]

It would seem JIS is not even the beginning of screw head complications!

[tenbikes]

I replace them with SS Allan key bolts. Look nice, no extra tools, no issues in 20 odd years and probably 40 odd bikes!

You have over 40 bikes! why are you called Tenbikes?

That's 40 over many years, but I usually run to ten at any one time. But currently only seven. And now that I've moved into a smaller property four would be ideal ......should probably sell the bamboo touring bike, the Midnight Special gravel/touring bike and the Ti gravel bike.
The four fatties with twelve wheel sets cover all my needs now. I think!

[Sweep]

I replace them with SS Allan key bolts. Look nice, no extra tools, no issues in 20 odd years and probably 40 odd bikes!

Don't suppose you have a link for correct size of these ss allen key bolts?
I might be interested in buying some.

[freiston]

Was pleasantly surprised as I had read some things online which seemed to say that JIS screwheads were a mytth, just the same as Philips in practice.

I think that this came from Japan changing from JIS to ISO some years ago - so what was a JIS screwdriver technically became an ISO screwdriver. I'm not sure, but I think the ISO standard for the "JIS type" is a sub category of the ISO standard that includes Philips or Pozidrive. So technically, a "Japanese screwdriver" is no longer JIS but a cross-head ISO, but in reality, it is still the same as JIS and different to Phillips or Pozidrive. I might be off in some detail or nuance but I'm sure the gist of that is correct.

[freiston]

I have some nice Vessel JIS screwdrivers that have like serrations on the external flat edges of the cross, designed to give even better purchase. I understand that the JIS screwdriver stands the best chance of working with other types of cross-head screw than the other types of cross-head screwdriver do.

Oops - almost forgot to say - I would be interested in those allen screws too - would make roadside adjustment a lot more convenient to do.