Thank you for the information. Paul_KD7HB I was hoping the air coupling would act as a thrust bearing for a short time. If I lube it and keep rotation to a minimum, at least for a short time. I believe they allow for rotation, otherwise I will have to allow for in some other way. Have you got any ideas on a bearing for that application? Maybe one with NPT connections, but I would like to keep it all in PVC to keep the corrosion down because of dissimilar metals and the salts. I can do stainless with the coupling.