Japanese industry standard screwdrivers

[BRT-GTR]

      Z,   See my correction above. Look forward to seeing you and the second GTR at Stafford. Good luck with the awards.
  
   Did a little research on JIS. Cross head screws are covered  by JIS B 1012, established in 1958, revised 64, 74 and 85. Without buying a copy of the documents, they don't say when the dot identifier was introduced. Most sites quote the 1985 revision, I think this is the most likely date.

More information here               http://www.instructables.com/id/When-a-Phillips-is-not-a-Phillips-Plus-So-Much-Mor/step59/JIS-Japanese-Industrial-Standard/

  The standard does seem to apply to the cross head shape only but may have covered the screw pitch. As well documented on our site and to help new members the 3,4,5,10 & 12mm screws used by BS have a different pitch to current ISO screws. Luckily the 6 & 8mm (most engine bolts) are interchangeable with ISO.
     Another piece in the jigsaw,     Brian.

[disc_valve]

Hi, Fellas,

I always understood that the dot marking on the head indicated an ISO thread. In the case of the case of 6mm and 8mm fasteners the dot is somewhat  irrelevant as the ISO and pre-ISU thread pitches are the same. In the case of 5mm (and smaller) fasteners. the ISO fasteners have a slightly finer thread pitch. As Bridgestones were all manufactured prior to 1971, they would have left the factory with pre-ISO fasteners. Over the years since then it is likely that various fasteners have been replaced, so they would have the "ISO" dot on them because that was all there was available.

Graham

[mqtsteve]

Thanks Brian and Graham!  Great info, as always.  I tried to contact stampman on eBay.  He didn't reply.  I don't need complete sets.  I already have several NOS replacements.  I know I can probably get them from Richard.  I only need a few screws.  Thanks for the input, Steve

[BRT-GTR]

    Just gets curiouser and curiouser 
 Graham is right once again, the dot indicates an ISO thread and probably an ISO screw head. See the article below, seems there are ISO drivers as well. JIS and ISO drivers have good compatibility. Just don't use phillips or pozidrive drivers on your BS screws.

       See ' Tech tip of the Month' towards the bottom        http://modelenginenews.org/ed.2011.04.html#tt

      My vessel drivers are marked P2 and P3 which doesn't help. I now suspect they actually have an ISO tip form which will happily work in JIS screws.

    Is that all clear then         Brian.   

[slawsonb]

Exceedingly clear...lol
Thanks for the effort to clear this up Brian and Graham. Very helpful.

[moonpup]

My JIS screwdriver.... nuff said 

[slawsonb]

I just bought one of these Motion Pro T-Handles.
http://www.motionpro.com/motorcycle/partno/08-0557/
Simply wonderful!
Ever try removing the long side screws from a 350 or 175 dynamo? Hard to do without damaging the screw heads, right?
I clamped a dynamo up in my soft jaw vise, and using the #3 JIS bit provided with the handle, a light twist with the mechanical advantage of the T and both came out with ease and no apparent damage to the heads.
Also makes cake of removing stubborn case screws.
Highly recommended tool. I have always had excellent results with Motion Pro stuff. (Not a paid advertisement...;-).
...bert

[moonpup]

Thanks Bert.... you just cost me $28 buckaroos!

Your dang glowing recommendation of that T-handle screwdriver had me so mesmerized I couldn’t control myself...... 

[slawsonb]

Sorry, was not my intent to mesmerize. Guess I should buy you a virtual beer!
...bert

[moonpup]

Shiner Bock please..... 

[slawsonb]

Comin' right up!

More comment about the tool described above.
I am working on an engine that has internal rust issues and several of the case screws are severely rusted (rotary valve cover in this case) and I have not been able to simply twist them out. Screws with compromised head integrity (rust or deformation from previous abuse) still require other extraction means. It can't make a bad screw good, darn!
...bert

[mqtsteve]

I just ordered six of the replacement bits.  They come in packs of two size #1, #2 and #3 for $3.50 each.  I ordered one of each with shipping for $12.54.  Called Motion Pro direct at (650) 594-9600.  6mm engine case screws are size #3.  Like Bert I was able to disassemble a 90 engine without marking/marring any of the screws.  Good luck, Steve