[AcampoDave]

I think youll be o.k. it looks like it just affected the first few threads in the hole. Get a plastic or brass one and try again. What happened to you is called "galling". Aluminum (and stainless steel) can do that sometimes. Brass doesn't because it "plays nice" with dissimilar metals and of course plastic won't do it either. If you use a plastic fitting there will be minimal risk because the plastic threads will munch up before the aluminum ones in the event you get a cross thread situation. The manifold has what's called "national pipe thread" or NPT. Common PVC pipe fittings are also NPT you can buy a cheapo PVC fitting in the appropriate size and use it for a test mule to see if all will be well when you thread in the real deal. EDIT: ANY TAP YOU MIGHT USE ON THE MANIFOLD SHOULD BE NPT.