[Bell Historians] clapper bushes

[Mrthigby at a...]

In a message dated 26/02/2004 14:06:05 GMT Standard Time, khsbelring at a... 
writes:

> I have been asked to advise on clapper bushes but have insufficient 
> knowledge of the subject. Is it possible for members to make some comments on why 
> they believe one type of bush is superior to another. Would the foundries care 
> to comment.; but please lets not get into a battle that could become 
> libelous. Howard E J Smith. - Newcastle. 

Hi Howard,

I have experienced many types of clapper bushes over the last 10 years (I 
estimate we have re-bushed nearly 80 sets, from leather baldrick's through to one 
mounted on ball races!).

My experience of modern materials is as follows:

1) Nylatron/oilon/oil impregnated nylon. 
These work well when used in conjunction with grease, and are quite hard 
wearing. Most of these materials were developed by the electrical engineering 
trade and are designed to self lubricate when used at a high RPM. With bells - the 
RPM is not high enough to get this material to self lubricate, so the 
material behaves similarly to a normal grade of cast nylon such as Nylon 66. As David 
pointed out - these materials also absorb moisture and can swell up gripping 
the pin (particularly in hot weather) - some bellhangers use them as standard, 
leaving a larger clearance for the clapper pin than normal.

2) PTFE Tufnol.
This in my experience is the best material for clapper bushes. Several local 
towers have these bushes fitted by Whitechapel, some of them having been rung 
to excess ever since (Ston Easton - 1970, Paulton 1970, Camerton 1971, and 
Swainswick 1973). I service 3 of these rings every year and therefore keep a 
close eye on wear. All of these bushes are as good as the day they were fitted and 
I have never known any of them seize up. This material is best used in 
conjunction with grease, however it still works (noisily) without. 
I have used this material for 8 years now without a problem - I used to 
purchase it from another bellhanging firm, but now buy it through the RS catalogue 
(Tufnol Kite Brand) - it comes in thick walled tubes.

3) Bronze/Brass/Oilite.
In my experience these work well when used in conjunction with grease, but 
can cause wear to the clapper pin (mild or stainless steel) when dry. In my 
experience the oilite does not produce enough lubricant without additional grease. 
A good material for keen steeple keepers! I have a pile of broken SG clappers 
outside my workshop, most of which have oilite bushes in them! Maybe because 
nylon has better shock absorbing qualities (this can be improved I suppose, by 
mounting the bushes in rubber).
As for wear - I re-bushed a set at Malmesbury some time ago, which came in 
with oilite bushes - most of which had worn through. I was told the oilite 
bushes were fitted about 5 years previously.

I hope this helps.

Matthew
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