I went to NAPA and found a castle(front wheel bearing adjusting)nut 27mm hex and welded a short 3/8" extension to the nut . AHA ! Now all I have to do is find it when the time comes .
FWIW , when you are installing the manhole cover , push it up into the cavity and slowly turn it CCW like you are removing it . When you hear it click , stop and start tightening the cover . no crossthreading again !