I'm converting a keggle with ss ball valve and nipple on outside. The nipple doesn't completely screw into the valve, only about 3/4 of the way. I was wondering if this is normal or if I might have a stuck part. I would try to return the part since it's so expensive, but i've seen some pics on the web where some of the threads on the nipples are still exposed .... so not sure if this is ok or i should return the parts?