Hi

There was a program on Discovery on that.

They took away material on the inside off the bell at the widest diameter.

If the "chiming bells" aren't seen by the viewer perhaps tuning forks would suffice, those metal prong type thingys which emit tinging sounds

2cents

The following is not from experience but what I remember / deduce from reading over the years.

The sound of a bell is a factor of the stiffness of the material and the circumference of the rim hence the size. Trimming the inside (only inside becasue it is not visible) on a thick bell eg cast one is a massively complex job but more to do with all the harmonics and overall sound rather than basic frequency Changing the frequency is more difficult on a small brass bell but might be achieved by hammer hardening and on a steel one by heat treatment to increase the strength and hence stiffness aswell as trimming the size.

A spiral gong is a bit like a piano string where mass per unit length has an effect aswell as length. Some experiment can be done by moving the clamping point to reduce the length before getting out the hacksaw.

Examples of clock bells of all shapes and sizes can be found . Bicycle bell is just one simplified version of the general gong type bell .

Look in pm's for picture of clock using basically bicycle bells but as castings . The original series of articles gives drawings of the bells and basic instruction for making and tuning .

I don't have the relevant issue now but I'm sure somebody else has . Circa SEP 1956 ME Musical Clock .

MikeW

If you want to tune your own bells I would buy or borrow a strobe tuner with a built in microphone otherwise unless you have the ears of a highly trained musician you will be driven to the point of madness. That way you can size you bells to a correct pitch and octave incase you fancy being cleaver and harmonising your bells around simple intervals or triads.

try this

<http://www.shoptlpwales.co.uk/index.php?route=product/search&filter_tag=vinco%2010%20Note%20Hand%20bells>

Glenn ,

Time for some more real engineering .

It often happens in real engineering work that a component or group of components has to be designed where there is really no useful data or guidelines available at all at the outset .

If a further trawl of information about bells and gongs is fruitless then you will need to design what you need from scratch – often a rewarding process .

Regarding proper bells : make say three nicely proportioned bells , each geometrically similar and in three sizes . Test each one for tone and pitch . Tone will probably be ok if they look anything like bells so only really test for pitch . Plot graph of pitch against a characteristic dimension . Then from your graph size bells actually needed for clock , make with just a little trimming allowance and fine tune as nescessary .

Regarding spiral gongs : same principle but since they are so easy to make compared with proper bells you could make more test ones . Geometrically similar but sized both on general dimensions and wire size .

Quite nice brass bells can be made simply by turning – no intrinsic need for castings .

I've seen spiral gongs with both round and rectangular wire But since round wire is going to be much easier to source that is what I would use . Wire is ideally hard so quite possibly piano wire in its as supplied form would be ok .

It is possible to design bells and gongs using theory and numerical calculation but I think the practical approach is the better one for present puposes .

MikeW

I have been on a tour of the Whitechapel bell foundry, and they said that only about half a dozen people in the country can tune a bell properly.

Regards

Geoff

When I visited Kallam Island museum in Sheffield back in 1984, the guide there told us about the bell they had there, I think from one of the battle ships, and how the person who was preparing the bell used to take it home to scrape a little off the inside until he got the tone right, don't remember all of the story, and maybe it was just a story (I know museums). Ian S C