So, wanting to get on with things this year I recalled that I had a couple of medieval type bells to re-create. I also have some instructions for their manufacture. Naturally my resources to make bells are limited, so I am looking mostly at the smaller sort.
However after doing some reading I thought it would be easiest to organise things to stimulate the actual making and associated blog posts by bell type and date, starting earlier.
The earliest information I have about bell making is from the 12th century On Divers Arts, by Theophilus, a work you will all no doubt be familiar with.
He gives some instructions for making two types of bells, one the familiar sort that is put in a tower and tolled, and the other that is hung up and hit with hammers. The shape of the two sorts is in fact quite different, something that I hadn’t really realised before.
I imagine this difference is down to the different acoustic demands from the bells, but more research is of course needed.
(This short article seems to point towards some answers: http://www.photomodeler.co.uk/applications/documents/bell_vibrations.pdf As far as I can gather, the bell studied vibrates in different modes, i.e. up and down, side to side, etc, at the same time, so obviously if your bell is very much different in shape it will produce different tones and such through vibrations being different)
The above photos show two bells, the one on the right definitely being medieval, the left one I think more post-medieval, made abroad judging by the inscription on it. Inscriptions on medieval bells is a whole ‘nother blog post by itself, they have been studied a fair bit. Anyway, note the very slightly different shapes, the earlier they are the more vertical the size, but both have raised ridges round the outside, allegedly from wire used to hold the mould together.
The smaller bells though, Theophilus hardly describes, instead spending time making sure you know that in order to make them sound in tune when playing, the amount of wax for each bell should be carefully controlled, and he uses the method of dividing the wax in proportions, halves, eights etc. So by volume, rather than by weight as a modern person might think of doing.
Unfortunately he doesn’t say exactly how the bells are made, one assumes the same way as the larger ones. Theophilus also points out that you have to be sure to use only the wax for the bell and add extra wax for the yoke by which it is hung and the vents for the mould. Which is very useful advice.
The translators of Theophilus helpfully include a 12th century drawing showing such small bells in use, from MS B 18, fol. I, St John’s College, Cambridge. This can be seen here, the bell player in the top left:
Usefully, someone on twitter also linked to this:
A 13th century German bell used in a refectory to signal the time to dine. It looks quite thick and heavy, but surely sound good when struck. I note that the yoke at the top has a seam on it, suggesting to me that it was made a little carelessly, when they smoothed the two parts of the mould together, or else it was not made of wax originally but a wooden or other pattern was used, which was then removed before the casting.
So the thing to do in the off season is play about with the wax I have and see what I can make, bellwise, starting with such bells.