for my 78 raleigh ghetto conversion, spun off the 1st 2 cogs (threaded) on the freewheel, the other 3 were splined and slid off. Spun the smaller threaded cog back on and presto, perfect chainline w/ the inner chainring. This was an old sun tour freewheel. This is if the old freewheel is threaded/splined. As for a lockring, I don't think it is even necessary; she'll only be pedaling in 1 direction with any significant force.