a/c port fittings

[Speedz]

i've got two a/c systems to charge..(90 ex cb7 and 92 si prelude) i've found an alternative to r12.. but my r12 gauges have the 1/4" flare fittings on them.. which is fine for the larger a/c fitting.. but the smaller one, i dont have an adapter for.. does anyone know the thread size for the smaller a/c port so i can find an adapter?

(btw i did search google & other places.. didnt come up with anything i trust)
thanks.

[lindiz]

The smaller high pressure port is 3/8". I got an adapter kit off eBay that works just fine, but likely a single adapter can be found.

[Speedz]

are you sure its 3/8" thats larger than the 1/4" flare fitting that fits on the larger a/c port

[lindiz]

The larger one should be 7/16" also the kit I got specified these thread sizes. I'm in Europe, I thought the ports were the same in USA but I could be wrong.

[Speedz]

thats a nice diagram, the problem i'm seeing is how the fittings are measured.. my r12 gauges physically thread on to a 1/4" flare fitting.. but the threads really dont measure 1/4" .. .. some refer to the Inner diameter of the hose/line and some refer to the outter diameter of the threads.. etc.. this is getting frustrating. i believe the 1/4" flare refers to inner diameter of the tubing... just to list a few types of threads.. JIC, AN, BSPT, NPT, ACME.. etc.. dammit!

[Speedz]

did some measuring. the outter edges of the threads measure 7/16" and 3/8" so that helps.. so does this image