Renewal of our clappers was urgently needed. In their un-repaired state, they were wearing away the inside surface of the bells where they strike, doing irreparable damage.
The first task was to insert new bushes into the staple (“hinge”) at the clapper top.
The black ring in the picture is a sleeve of self-lubricating Tufnol that allows the clapper to swing on the white staple bolt.
A worn bush allows the ball at the other end of the clapper to swing in a Figure of Eight pattern, scrubbing across the surface of the bell, abrading the bell metal.
Photo: Matthew Higby & Co Ltd.
The second task will cure two problems.
The shaft of the clapper is carefully heated in a blacksmith’s forge and it is then twisted slightly so that a fresh, round surface of the ball gives a single point contact on the ball’s surface.
Not only does this decrease the wear, but it should also give the bells a brighter, crisper tone.
Once twisted, the shaft is allowed to cool under controlled conditions, allowing the iron molecules to “relax”, relieving the stresses that have built up over their 110 year life and helping to reduce the danger of a disastrous break.
Why is a broken clapper a disaster?
Over hundreds of years, the ideal metal for clappers has proved to be wrought iron. This traditional material is ideally suited to withstand the stresses and vibrations created as the clapper strikes the bell. A hard steel clapper would simply shatter.
Sadly, since around the 1970s, good quality wrought iron has become virtually unobtainable. The great metal-producing companies only make steel in various different configurations. The traditional blacksmith who would “wreak” (I think that’s the right word!)
iron is also becoming a rarity. Bell hangers fight over the good ones!
Modern clappers are cast in “Speroidal Graphite Iron” and they tend to be heavier and less satisfactory – but it’s the best that we can get nowadays. For big bells, an alternative is to bolt the heavy metal clapper ball to a stay made of ash timber which is lighter and more resilient. These are only recommended for bigger bells as they don’t behave so well in smaller sizes. Should one of our clappers break, we would first of all have to try to find a second-hand wrought iron clapper that is just the right size. They don’t recommend mixing SG Iron and Wrought Iron clappers in the same ring of bells as they sound different. Such clappers are hard to find.
Why are some repairs a Bad Idea?
In the past (and sometimes now), the habit was to repair a worn clapper by filling the missing part with weld and then grinding it down to the correct profile. This process was damaging to the bells because the weld material is harder than that of a bell and this increased wear to the bell, rather than reducing it. It was the assurance that our chosen bell hanger (Andrew Nicholson of Bridport) would not be following this practice that helped us to select the company to do this work.
Matthew Higby, another well-respected bell hanger alerted us to this dangers of this practice – and it is his photo shown above, though he is not doing our bells.