<HTML><FONT FACE=arial,helvetica><HTML><FONT SIZE=2 PTSIZE=10 FAMILY="SANSSERIF" FACE="Arial" LANG="0">In a message dated 26/02/2004 14:06:05 GMT Standard Time, khsbelring@a... writes:<BR>
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<BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">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 bushis 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. </BLOCKQUOTE><BR>
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Hi Howard,<BR>
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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!).<BR>
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My experience of modern materials is as follows:<BR>
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<U>1) <B>Nylatron/oilon/oil impregnated nylon.</B></U> <BR>
These work well when used in conjunction with grease, and are quite hard wearing. Most of these materials were developed by the electrical engineeringtrade 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.<BR>
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<B><U>2) PTFE Tufnol.</B></U><BR>
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. <BR>
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.<BR>
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<B><U>3) Bronze/Brass/Oilite.</B></U><BR>
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 myexperience the oilite does not produce enough lubricant without additionalgrease. 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).<BR>
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.<BR>
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I hope this helps.<BR>
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Matthew<BR>
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