If that's an old steel 1/8" Peugeot chainring, it probably weighs a ton already... so I suppose you could weld a steel disc with a narrower diameter opening (40 mm.) into the center, and then drill it for use with an old TA 5-pin or Stronglight 49-d crankset before you have it re-plated in chrome or nickel...

I'd be careful to drill it so the crank arm would exit at one of the points where the arrows meet at the edge of the chainring. With a threaded cottered cranks (like the one shown at the left) this could not be easily done because the threads just stopped the crank arm when it could tighten no more.