diameter of #48 propane orifice
If memory serves, the old numerical schedule works out about .076". Note that propane cylinders operate at 1/3 higher pressure than LNG cylinders. Although American cylinders are required to have left-hand threads on all fuel connections, and right hand threads on all oxidizer or inert connections, that does not necessarily apply to Canadian tanks built before 1988.
If the amount of rust on the tank in your photo is any indicator of the condition of your tank, I would be most hesitant to keep it. Most propane jobbers will trade out your old tank for new, often without charge if you sign a contract to buy your fuel from them.
Disposing of old rusty fuel tanks takes specialized equipment and training. This is not something a do it yourselfer should attempt.
American Patriot aka Rocmike has stolen Dfrogpongs moniker. This lonely insane loser has been posting 31 out of the last 39 hours under Bill, Tweek, dfrogpong, Ladydarko, Rick Barnett, Bob Suffolk, Top Renner, Anonymous, Humble, Lady Aban who is still posting and a few others. Now Top Renner is posting. This loser needs help and a life.