church bell. 2nd installment

Subject: church bell. 2nd installment
From: GUEST,leeneia
Date: 27 Jul 05 - 11:39 AM

We've been running a thread on how best to fix the clapper from the bronze bell (c. 1870) at my church. The shaft of the clapper had broken through.

I appreciate the help of all the metal-workers of various stripes who contributed. We printed off the entire thread, ruminated over the insights, and then gave it to the other clapper-retriever. He sent a message as follows:
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Clapper is actually forged steel...determined by "spark testing". My machinist recommended welding. I told him this was God's bell and that clapper failure would result in a blight of locusts. He stood his ground, so I told him to go ahead.

I had my tool designer (a retired metals systems designer from
Honeywell) look at it after the repair had been competed. He said that it should be fine. He offered an alternative of tapping 3/4 inches into the end of each section, inserting a 4140 threaded stud (Rockwell C 35-38) and running a shallow bead around the joint.

It seems that any failure in the clapper would result in a repeat of finding the clapper laying underneath the bell. In that event we could try the threaded insert alternative or try to find a blacksmith with the necessary knowledge to forge weld the pieces.

I did a search for bell/clapper info on the net and came up with some insight on tone quality. The flattening on the clapper contact surface is a bad thing tonewise, so I had them rotate the pieces 90° to put the proper surfaces in contact with the bell. We also installed a bronze bushing in the eye of the clapper and replaced the bolt and nut.
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This Friday evening, the clapper goes back into the bell. I have a crucial role - feeding the guys afterward. I will also be on the ground, listening for a beautiful new tone from the restored bell.

What is a bushing, anyway?

Subject: RE: church bell. 2nd installment
From: Highlandman
Date: 27 Jul 05 - 12:33 PM

A bushing is a cylindrical piece with a hole through the middle, like a short piece of pipe. Used basically for making a large hole smaller, sometimes for repair purposes and sometimes to line a soft material with a harder one for wear resistance. Et cetera. In this case the bronze bushing probably was to make a worn out hole a bit smaller and also to act as an anti-friction material. Should last longer than the original before wearing to an unreasonable amount of sloppiness.
Hope that helps.
-HM

Subject: RE: church bell. 2nd installment
From: JohnB
Date: 27 Jul 05 - 12:36 PM

So you had to go and weld it, shame, shame, shame. There are still enough Blacksmiths around to do a proper repair, which personaly (not just being a Blacksmith) I would have gone for on an 1870ish restoration.
Anyhow, a bushing is basically a length of tube, being bronze it will wear out faster than the iron parts which it is rubbing on (this is termed a "sacraficial bushing") So when you check the clapper in ten years or so, you just knock out the worn bushing and replace it with a new one, with no structural damage to the steel parts.
I hope you will be singing one of the Cornish Bellringing songs on Friday.
Good Luck, JohnB

Subject: RE: church bell. 2nd installment
From: MMario
Date: 27 Jul 05 - 12:40 PM

we expect reports on the renewed musicality of your bell.

Subject: RE: church bell. 2nd installment
From: Highlandman
Date: 27 Jul 05 - 12:54 PM

John B is right in the sense that the bronze bushing is replaceable and will wear faster than the steel bolt. But different metals (bronze on steel) will have less friction and usually less wear than if the hole and the bolt were made of the same material.
But no one will care about this sort of thing by Friday evening, when they hear the bell again, will they? :-)
All the best
-HM

Subject: RE: church bell. 2nd installment
From: The Fooles Troupe
Date: 27 Jul 05 - 07:08 PM

"Sacrifical Bushing" ???!!!! Hmmmmmmmmm..... sorry - that's off this topic.... ;-)

Subject: RE: church bell. 2nd installment
From: Peace
Date: 27 Jul 05 - 07:14 PM

JohnB: There is a sloop named after you.

Subject: RE: church bell. 2nd installment
From: The Fooles Troupe
Date: 27 Jul 05 - 07:44 PM

That's the one they caught the next day - but who remembers the one that got away? :-)

Subject: RE: church bell. 2nd installment
From: GUEST,leeneia
Date: 28 Jul 05 - 10:34 AM

I didn't know they were going to get it welded it so fast. The proof of the ringing is in the listening, so we shall see how it sounds on Friday. Will be have the musical "bong" which my mechanic desires? We shall see.

I'll tell the church management to put in the maintenance books that the bushing needs to be check every few years. Step one of this process is finding someone who can handle the height up there.

Subject: RE: church bell. 2nd installment
From: MMario
Date: 28 Jul 05 - 10:35 AM

Mind the friction - don't want a burning bushing

Subject: RE: church bell. 2nd installment
From: JohnInKansas
Date: 28 Jul 05 - 10:42 PM

There are lots of different "bronze bushings" available, but assuming a knowledgeable choice of an appropriate one, and a proper installation, it's a rather glib assumption that "the bushing will wear out faster."

The original arrangement apparently was an iron/steel bolt in an iron hole. When two ferrous metals rub against each other, especially when they rub slowly, there is always some friction welding (at micro level) that tends to tear loose tiny particles. These particles usually "rust" or otherwise chemically combine with whatever crud is present to make abrasive particles - often much harder than the parent materials - that then continue to produce additional wear in the joint. Wear on either side of the joint - bolt or bore - produces an "out of fit" condition that can accelerate the wear.

An appropriate bronze bushing should prevent this kind of fretting damage. The bronze against steel rubbing won't generate abrasives like iron on iron. Many fairly common "bronze bushings" are of sintered material - lots of tiny grains packed and fused together - that provides some space for impregnating "dry lubricants" that can greatly extend the life of a slow-motion joint of this kind. A variety of lubricants are available, with teflon being one that's common now.

Especially if it's a sintered bronze, any particles that are generated by bell motions will mostly embedded into the bronze so that they don't roll around in the joint and cause additional wear.

Just because it looks simple, doesn't mean it's not a sophisticated and effective device. At one time, the guy who used them had to know a lot to get a good joint, but now the "off the shelf" parts have all the goodies built in.

John

Subject: RE: church bell. 2nd installment
From: GUEST,leeneia
Date: 28 Jul 05 - 11:24 PM

Thanks for the info. If the bushing doesn't have dry lubricant, where would I get some? I'm familiar with Teflon tape for plumbing jobs. Would that be the same kind? We probably have some in the basement?

Subject: RE: church bell. 2nd installment
From: The Fooles Troupe
Date: 28 Jul 05 - 11:35 PM

One of the older simpler cheap dry lubricants was graphite powder that used to come in a little plastic 'puffer pack' - often used for locks.

Subject: RE: church bell. 2nd installment
From: JohnInKansas
Date: 29 Jul 05 - 01:22 AM

If the bushing didn't come pre-impregnated with the lube, it can't be added later, although the joint can be maybe be "greased." Not to worry too much about that, since the bronze itself is fairly "lubricious" in contact with an iron/steel bolt/shaft.

If the bushing wasn't prelubed, it could be a fair idea to have someone climb up and slop some grease on occasionally; but I wouldn't see this as a necessary activity. It would be a good notion - just as routine maintainance - to have someone do at least a "visual" on the condition of the whole bell on maybe an annual basis - at the same time that they check for loose shingles and such. If they're so inclined they could take an oilcan up and give it a squirt or two. Common auto engine oil (30W or so) or gear oil (90W?) would probably be as good as anything.

If you have to add a lube after the fact, an automotive chassis grease (Lithium base probably) would be a fair choice for an intitial slobber when the bell goes up, since it's made to get into the cracks and is intended to work in low speed joints and to stay in place.

I'd be inclined to trust the guy that picked the bushing. He may have "lubed" it when he installed it, but if he didn't it probably doesn't need it - or he would have told you what to do.

The replacement of the bolt, incidentally, was probably a wise choice. The durability of a low speed bushed bearing depends on both parts, journal and shaft, being round and well matched in size. The old bolt can be "archived" as a paperweight in the display case where the relics are kept - properly labelled for future generations and entered into the archive documents, of course.

John

Subject: RE: church bell. 2nd installment
From: open mike
Date: 29 Jul 05 - 02:16 AM

this reminds me of a hilarious skit by Johnny Carson and Jack Webb..
about a robbery...(a caper) discovered by cleaning woman Clara Clifford
the copper clappers were kept in the closet.
the suspect who copped them was Claude Cooper
He was from Cleveland--a kleptomanaic..

this 1968 gem about the Acme School Bell Company
was sent to me attached to e-mail just a while ago.
it is side splitting as opposed to wrist slitting.

Subject: RE: church bell. 2nd installment
From: GUEST,leeneia
Date: 29 Jul 05 - 12:25 PM

I think you're right John. I bet the metalworkers have already taken care of the lubrication issue. I'll just ask and make sure.

open mike - judging from its alliteration, I suspect the skit dates from the period of Beowulf. The Beowulf poet was crazy about alliteration too.

Subject: RE: church bell. 2nd installment
From: MMario
Date: 29 Jul 05 - 12:29 PM

I'm gonna have to wait until Monday to hear how the bell sounds! Dang, dang, dang!

Subject: RE: church bell. 2nd installment
From: The Fooles Troupe
Date: 29 Jul 05 - 06:26 PM

Yes, We're all in suspenders till then...