According to desperado :

I have never seen taps, dies or even rethreading taps and dies to cut garden
hose thread, which I believe is 3/4 11 1/2 size.
Anybody have any sources?--

It is called a lathe. And not all will cut 11.5 TPI, so make
sure of that first.

Then learn to cut threads on a lathe -- both external and
internal.

Good Luck,
DoN.
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