I had converted my Apollo (27" wheel) road bike to fixed wheel when I was at school, the chap across the road from my parents is a keen cyclist (He is now in his '60's, has had a heart bypass and still rides an early '80's Dawes Galaxy, Audax stylee with Mavic hubs and Simplex gears
) and he gave me a 27" track rear wheel.
I don't remember that having a lock ring. But it did have 2 cogs, so it was a proper fixed hub. Unfortunatelty that bike was thrown out by my parents when I went away to sea, obviously figured that I would not need it when I had newer ones there. I am glad I have my own house now!
Somerset, like 'Heartbeat' with newer cars!
Retro MTB: 1992 Cannondale M1000 Deore XT M730. 1992 Raleigh Dyna Tech Quantum Deore XT.
Retro Road: 1992 Eddy Merckx Corsa Extra Telekom Shimano 600 STI. 1993 Dyna Tech Ti Campagnolo Athena 8 Ergopower.
Modern: 2004 Wilier scandium Ultegra 6600. 2014 Wilier GTR Ultegra 6800.