Ever wondered why Japan cross-head screws get buggered ?
Discussion
After working on bikes for more than 40 years, I learned something new recently.
I always thought the japanese cross-head screws with a little dot on top were meant to be metric,
as opposed to imperial-based bolt sizes the japanese manufactureres used in the 50s and 60s
when they copied many western bike Engineering, got told this in my appenticeship ages ago.
The truth is that seemingly no one is using the right tool for these screws,
as their heads are "japan industrial standard" or jis and NOT philips or Pozi-Drive,
more info here : http://www.webbikeworld.com/motorcycle-tools/jis-s...
and here : http://www.ikaswebshop.com/jisphilips.html .
As a result of this, I ordered a (cheaper) set of #1,#2 and #3 here: http://www.rjrcooltools.com/shop_item_detail.cfm?s...
Maybe you can find them somewhere else on the net or over a UK Counter.
Smaller Versions of jis screws are also used in RC cars and computers, look for the dot, mostly it´s there,
and smaller bits or screwdrivers are sometimes available, but not the sizes screwed on bikes.
My teacher in the workshop was not completely wrong, as jis screws with the dot are ISO metric threaded,
as opposed to jis threaded bolts used before 1967 that are very unique and nowdays a very rare thing.
I always thought the japanese cross-head screws with a little dot on top were meant to be metric,
as opposed to imperial-based bolt sizes the japanese manufactureres used in the 50s and 60s
when they copied many western bike Engineering, got told this in my appenticeship ages ago.
The truth is that seemingly no one is using the right tool for these screws,
as their heads are "japan industrial standard" or jis and NOT philips or Pozi-Drive,
more info here : http://www.webbikeworld.com/motorcycle-tools/jis-s...
and here : http://www.ikaswebshop.com/jisphilips.html .
As a result of this, I ordered a (cheaper) set of #1,#2 and #3 here: http://www.rjrcooltools.com/shop_item_detail.cfm?s...
Maybe you can find them somewhere else on the net or over a UK Counter.
Smaller Versions of jis screws are also used in RC cars and computers, look for the dot, mostly it´s there,
and smaller bits or screwdrivers are sometimes available, but not the sizes screwed on bikes.
My teacher in the workshop was not completely wrong, as jis screws with the dot are ISO metric threaded,
as opposed to jis threaded bolts used before 1967 that are very unique and nowdays a very rare thing.
No, Pozi-Drive have a big cross and a little square inside if you look closely.
Chepaest Workaround is to use the size 2 screwdriver supplied in original bike tool set,
or grind the tip off a 1,2 or 3 sized philips tip :
https://www.youtube.com/watch?v=z1QyyK0STk0
Chepaest Workaround is to use the size 2 screwdriver supplied in original bike tool set,
or grind the tip off a 1,2 or 3 sized philips tip :
https://www.youtube.com/watch?v=z1QyyK0STk0
No. 2 or 3 Philips always worked for me.
The cross-head was invented when cars were still coach-built and used slotted screw heads, the idea was that the screwdriver would jump out of the cross at a certain amount of force (rather than chew the head), which is why they're hard to get out once tight - the driver is MEANT to slip.
Pozidriv was created once the car makers had gone over to air-powered screwdrivers with torque clutches: now you DON'T want the driver to slip out of the screw but stay in until the clutch slips, hence the redesign (effectively two crosses).
The first tool I bought when I got my first bike was an impact driver, it was the accepted way to get Jap engines apart
The cross-head was invented when cars were still coach-built and used slotted screw heads, the idea was that the screwdriver would jump out of the cross at a certain amount of force (rather than chew the head), which is why they're hard to get out once tight - the driver is MEANT to slip.
Pozidriv was created once the car makers had gone over to air-powered screwdrivers with torque clutches: now you DON'T want the driver to slip out of the screw but stay in until the clutch slips, hence the redesign (effectively two crosses).
The first tool I bought when I got my first bike was an impact driver, it was the accepted way to get Jap engines apart
A set of three Vessel JIS screwdrivers is available from Ruggedroads. They look like decent quality tools.
Having suffered the pain of chewed-up cross-head screws on various bikes, I now always try a selection of Philips and Pozi driver sizes and use whichever one fits best. I still prefer to replace the soft, cheese-like, quick-rusting OEM bolts with decent cap-head or Pozi ones, though.
Edited by MC Bodge on Saturday 14th February 07:41
Mr2Mike said:
A set of three Vessel JIS screwdrivers is available from Ruggedroads. They look like decent quality tools.
This is a bargain, good find.Gassing Station | Biker Banter | Top of Page | What's New | My Stuff