Cab I see a "2 ring rubber" and a "teflon" & a "teflon & rubber" on page 39 & the listing says a machining tool is needed for all of the three. I'd like to avoid another trip to the machinist if possible. EDIT Oh is that tool just to get the OD correct for the seal & it will stay put? The tool does not machine any special grooves or something trick to grab the seal & keep it in place? If so, the guide nub OD might be OK as is.