I discovered by accident that cutting the bottom off a small empty oxygen tank makes a great sounding bell, and since my front doorbell hasn't worked for years, decided to make one of materials I had left over in my shop. I have no idea if this has been done before but here it is:
Step 1: Cut the Tank in Half
After making sure the tank is empty, cut it in half. I hear that oxygen is flammable so be careful here. I personally had no problems with the sparks from my grinder cutting wheel and used the existing weld joint as a guide for cutting it evenly.
Step 2: Grind Edges Smooth
Just touch up the sharp cut edges with either a grinder, files, or belt sander.
Step 3: Save the Bottom Half for Something
the bottom half makes a great pencil or tool holding cup for the shop.
Step 4: Drill Out the Valve
Drill out the gas valve on the top so a string or wire can thread through.
Step 5: Tie the Ringer
Find something to use as a ringer. I appropriated the end of a bathroom faucet handle, and knotted it to a piece left over electrical wire and threaded it into the top, using a tied-in nut to keep it from sliding too far inside the bell, after marking where I wanted it on my wire.
Step 6: Tie the Ringer Handle On
Attach a handle to pull on. I found an old lighting pull switch handle to tie on the end. Anything will do.
Step 7: Attach to a Hanger
A left over circular cut out made of poplar functions as a plate through which to thread a long bolt that works to hang a chain I attached to the bell. The bolt head is counter sunk on the back side so it sits flush against a wall, and a few nuts and washers keep the chain in place.
Step 8: Attach to Wall.
After pre-drilling screw holes attach the hanging bell onto a wood trim piece next to the front door and Voila: old school doorbell. Sounds much better than an electric one in my opinion.