8 TPI, 1" min diameter, 1.08" max diameter. The thread form is rounded
like an acme thread although I don't know if it's exactly the same.

For backyard-type experiments, the most common method to attach
plumbing is to drill the hole in a bottlecap and put a Schrader (tire)
valve in there. From there you can adapt to whatever you want.

Tim.