O ring sizes

[froche]

When Honda says 46x2 o ring exactly what are they saying?
46 mm id or od?

When ordering o rings from an oring "house" the first number is usually id, I know the 2 means cross section (diameter of the "rod" making up the oring)

So would the Honda 46x2 be a 46 od x 42 id x 2 cs or
50 od x 46 id x 2 cs?

[OldguyGlen]

O-ring format:
1st # is ID, 2nd # is cross section of perimeter "rod".
So a 46 x 2 o-ring is 46 mm ID, 50 mm OD and made with a 2 mm dia "rod".

Try to get an official metric o-ring when you can. But hard to find rings sometimes can be found at ACE hardware (and other common source retailers) by substituting a close match in SAE (inch dimensions) When in doubt, choose a slightly smaller ID as they will stretch a bit (don't overdo the stretch thing though.) If you can't find the original spec, you can measure the OD of the metal piece (groove) as a starting point.

[froche]

Thanks for the reply, but still not an answer.

I get orings on line, metric, SAE, Fractional and JIS sizes are available. The 46x2 is available for .25 from there but i still need to know if Hondas 46x2 means 46 id or 45 od.

[gipsy42]

Hi Froche:
A little search allowed me to find this tech spec in the www.sealanddesign.com site:

" Japanese Metric O-Rings (JIS)

The Japanese Industrial Standard (JIS B 2401) contains three groups; aerospace group, general purpose group, and traditional group. These o-ring sizes are unique to Japan's automotive, semiconductor, and manufacturing industries.
JIS O-Ring Groups
Aerospace Group
367 sizes and follows ISO 3601-1 very closely (with a few extra sizes).
Each size is designated by its dimension: ID × cross-section. Subsequent to the dimension, the letter "A" is appended to indicate use in aerospace applications.
General Purpose Group
Contains 445 sizes and matches ISO 3601-1 very closely (with a few extra sizes).
Each size is designated by its dimension: ID × cross-section. Subsequent to the dimension, the letter "G" is appended to indicate use in general purpose applications.
Standard metric sizes for O-rings are defined by International Standard ISO 3601-1 Fluid power systems O-rings Part 1: Inside diameters, cross-sections, tolerances and size identification code. That standard groups metric sizes into two series, G and A. The G series is used for general purpose applications and includes a wide range of inside diameters. The A series is used for aerospace applications where tighter tolerances are recommended. The G series has 445 sizes and the the A series has 383 sizes. "
I hope this is what you're looking for.
Regards.

[froche]

But Honda o rings are mentioned in the parts book as 46x2
46 id or 46 od?
A simple question that nobody has answered though you may have found that a 46x2 Honda o ring, according to JIS specs you provided, is 46 id x 2 cs. That means that it is 46 mm id, 50 mm od and a 2 cs.

I guess I am going to have to take apart something and measure it!

[WingAdmin]

But Honda o rings are mentioned in the parts book as 46x2
46 id or 46 od?
A simple question that nobody has answered though you may have found that a 46x2 Honda o ring, according to JIS specs you provided, is 46 id x 2 cs. That means that it is 46 mm id, 50 mm od and a 2 cs.

I guess I am going to have to take apart something and measure it!

Two people have already given you the same answer!

Metric O-rings (of which Honda uses, of course) are ID x diameter. So a 46x2 is as you say, 46 mm ID, 50 mm OD, 2 CS.