JIS Pitch

[quidger]

Someplace I have seen a JIS pitch chart that shows the pitch for each size of metric screw and bolt. At some point in the 70's the pitch on some sizes changed but I can't seem to locate a chart. I thought it was on my Bill Silver CD but can't even find it on there.

Can someone help me?

Thanks

[OldHarley]

Guess there are no takers, so, I remembered seeing this well described chart that shows several types of JIS threads - parallel, tapered, etc.

http://www.ring-plug-thread-gages.com/t ... le-JIS.pdf

I would think that the metric standard (M) JIS is the one you need, but my experience is more on American bikes, so I am somewhat a novice at this.

I am still figuring out why the JIS fasteners on my '64 250 Dream aren't marked with a dimple or 'X' to help me out when I need a screw or bolt. At least then I would know the local hardware store didn't have any stock.

Oh well, maybe it is all JIS. So I continue to search.

[Hotshoe]

See if either one of these sites helps you.

www.mcmaster.com
http://mdmetric.com/tech/threadtech.pdf

[brewsky]

The info is in the Bill Silver printed guide, so it should be there somewhere.

The change date was 1967 per Honda bulletin.

Basically, only the 3, 4, 5, and 12mm thread pitches changed. The rest are the same and interchangeable with current metric sizes.

The bolt head sizes (wrench sizes) changed on some others, but the pitch is ok.

[rzgkane]

Page 63 of Silver's Dream Restore 2010 file.

[conbs]

I believe brewsky is right about the 4 sizes that are different. If I have my information correct the JIS pitches are as follows:

3mm is .6 pitch vs .5 pitch for ISO
4mm is .75 pitch vs .7 pitch for ISO
5mm is .9 pitch vs .8 pitch for ISO
12mm is 1.5 pitch vs 1.25 pitch for ISO

BTW this info is from Honda Service Letter #74 of 6/8/67 found on pg 63 of Bill Silver's 2006 Restoration Guide.