Tempering a bell.

[wow]

I just got a very old tall case clock in which someone replaced the big bell with a new iron bell. The bell is about 6 inches around and about two inches high. It is about 3/16 inch thick. It sounds terrible. Dead! No ring. Gray in color. Seems very soft. My question:
Has anyone ever attempted to temper such a bell? Will tempering it make it ring? How would you temper it? Thoughts?
Will

 

[J. A. Olson]

Check for cracks in the bell, even the smallest crack will kill the sound.
Some coil gong wires have been annealed with heat from small torches or cigarette lighters. I don't know of anything like that being tried with bells and yielding successful results.

 

[Mike Phelan]

I'm with Justin on this - if a bell doesn't ring, it's cracked.

 

[wow]

It is not cracked. I have no use for it as-is. I have three other bells that are a bit smaller and all ring well. All look like they have been tempered at some point. I think I’ll find someone in my area who has a forge and get them to heat it red hot and then drop it into cold water. What do you think?

 

[J. A. Olson]

The cracks referred to can be microscopic, meaning you may not see them from a typical viewpoint. You'd have to put the bell under a microscope to see where any cracks may be developing. If those microscopic cracks develop further, they will eventually become more visible and apparent.

Anything's worth a try if it hasn't improved with other techniques.

 

[Jim DuBois]

Even cast iron will ring if not cracked. And cracks, just as others have already suggested, can be microscopic. I have a bell right now that shows no cracks but does not ring. It is cracked, just because I can't find it means nothing. A few months ago I dropped a non-ringing bell on my concrete floor and suddenly had a bell in 3 parts.

If the crack is found it can be braised/silver soldered at the crack and ringing is restored. I have done that successfully once or twice. Usually, just finding another uncracked bell works best and with a lot less frustration.

 

[novicetimekeeper]

Big Ben, the hour bell on the Great clock of Westminster, has a crack and rings fine. Perhaps because it is so big.
This bell looks like it was on a posted frame movement originally, where it would be struck on the inside. A smaller bell would be more original.

 

[wow]

Well, I have been convinced. I will check closer for a crack. It almost sounds like it is made of lead. My grandson is a good welder. May be a project for him. I’ll report back. Thanks, guys.
Will

 

[Jim DuBois]

and our liberty bell is also cracked. But the crack is "stopped" with bolts so it still rings.

 

[wow]

Big Ben, the hour bell on the Great clock of Westminster, has a crack and rings fine. Perhaps because it is so big.
This bell looks like it was on a posted frame movement originally, where it would be struck on the inside. A smaller bell would be more original.

I have several bells about four inches around that ring fine but the mounting post is cast and cannot be bent and I don’t want to re-mount it in a different place. The hammer tail is very stiff cast iron and may break if I try to bend it. It needs the bigger bell. I’ll find one if I can’t fix this one.

 

[novicetimekeeper]

both the bell stand and the hammer will be wrought iron.

 

[wow]

I found something else. The hammer tail has a stop on it that is not doing its job. It is worn and does not stop the hammer tail before it hits the brass horizontal post above it. The bell still sounds bad when struck with a steel object but I will need to adjust that tail so the head strikes the bell only and bounces off. Right now the tail stops on the post. Both problems need to be addressed. Will report back.

 

[novicetimekeeper]

I found something else. The hammer tail has a stop on it that is not doing its job. It is worn and does not stop the hammer tail before it hits the brass horizontal post above it. The bell still sounds bad when struck with a steel object but I will need to adjust that tail so the head strikes the bell only and bounces off. Right now the tail stops on the post. Both problems need to be addressed. Will report back.

The hammer is currently resting on the bell, which isn't right. It should start with a gap, bounce off the stop, and strike the bell, then go back. The shaft of the hammer is cracked where it has been bent back to accommodate the larger bell.

 

[R. Croswell]

………… I think I’ll find someone in my area who has a forge and get them to heat it red hot and then drop it into cold water. What do you think?

if it isn’t already cracked, it probably will be.

The hammer is currently resting on the bell, which isn't right. It should start with a gap, bounce off the stop, and strike the bell, then go back. The shaft of the hammer is cracked where it has been bent back to accommodate the larger bell.

Definitely a problem, maybe THE problem.

 

[Willie X]

Oh come on ... I wanta see what a red hot cast iron bell does when you drop it in th water. Willie X

 

[wow]

In the photo it is resting on the bell. The bell is not perfectly round and I had just turned it so the hammer would touch it. I have turned it back to the point where there is tiny space between the hammer and the bell. Still clunks. I have removed the bell and mounted it on a rod in a vice and it still clunks. It’s the bell that is bad because I mounted another bell on the clock and it rang well. I can’t see a crack. So off to the forge. Will let you know.

 

[gvasale]

Is the bell sitting on a leather washer and is there another leather washer under the nut?

 

[wow]

Is the bell sitting on a leather washer and is there another leather washer under the nut?

I’ve tried it on leather and on steel and it still clunks. If it is hairline cracked I can’t find it. I am searching for a local forge. Tempering it cannot make it worse. Right now it is useless.

 

[R. Croswell]

I’ve tried it on leather and on steel and it still clunks. If it is hairline cracked I can’t find it. I am searching for a local forge. Tempering it cannot make it worse. Right now it is useless.

You might be able to take it to an engine rebuilder or well equipped machine shop and have it magnafluxed which is a way they locate “invisible“ cracks in engine castings.

RC

 

[wow]

Never thought of that, RC. Thanks.

 

[TQ60]

You can try a rag with some paint or dye.

Scrub the bell surface and a Crack will scrape in the paint sometimes.

 

[Chris.K]

As TQ60 said, get some dye that glows under UV light. Put it in a spray bottle and coat the bell then look under black light for cracks or "spider-webbing" which is a casting flaw, be sure to check both sides. Plus you can use the dye in the future for looking at case marking and such. Chris..

 

[Jim DuBois]

or maybe just replace the bell with a good one? They are not expensive, they are around, and it will cost far more to mess with the failed bell than it will cost to replace it.

 

[bkerr]

Any good weld supply will have the cleaner, dye and penetrate. Will cost you about $30.00. I just repaired a cast bronze bell for a small French carriage clock. Someone tried solder, really lead for sound! So I cleaned that all off and used silver braze 45% and it worked well.

 

[wow]

or maybe just replace the bell with a good one? They are not expensive, they are around, and it will cost far more to mess with the failed bell than it will cost to replace it.

View attachment 765151

You are 100% right, Jim. I’m just interested in seeing if tempering will make a difference. If it is cracked, though, I know it won’t. Gonna check for cracks as suggested above first and if it is not cracked, gonna try tempering just for fun.

 

[Bernhard J.]

Before all that, perhaps take a watchmaker hammer and hit the bell lightly at different places, near the rim and stepwise further inwards. I have made the experience that the sound of a bell may differ considerably, depending on where it is hit.

 

[Bernhard J.]

Before all that, perhaps take a watchmaker hammer and hit the bell lightly at different places, near the rim and stepwise further inwards. I have made the experience that the sound of a bell may differ considerably, depending on where it is hit.

 

[wow]

Before all that, perhaps take a watchmaker hammer and hit the bell lightly at different places, near the rim and stepwise further inwards. I have made the experience that the sound of a bell may differ considerably, depending on where it is hit.

Thanks, Bernhard. I have tried that and it sounds the same everywhere. DEAD!

 

[R. Croswell]

You are 100% right, Jim. I’m just interested in seeing if tempering will make a difference. If it is cracked, though, I know it won’t. Gonna check for cracks as suggested above first and if it is not cracked, gonna try tempering just for fun.

Will be interesting to see what happens. I may be wrong, but I've never heard of tempering cast iron (cursed iron). My money says if it doesn't bust while being heated, it will as soon as it hits that cold water.

 

[wow]

Will be interesting to see what happens. I may be wrong, but I've never heard of tempering cast iron (cursed iron). My money says if it doesn't bust while being heated, it will as soon as it hits that cold water.

You’re probably right, RC. I was thinking the same thing but what’s to loose? It’s dead as-is

 

[Jim DuBois]

Not to be pointed, but bells are not tempered in their manufacturing process. Tempering by definition is heating a ferrous metal, usually steel, to a high temperature, usually above 1830 degrees, and then quenching it in oil or water or in some case air cooling.

Cracks that occur when they are not properly cooled when made, or from impurities in the original material or just simple casting flaws. They may, and often do fail when first cooled. Verdan states that as many as 2/3rds of their cast bells fail and have to be recast. Of course, those are bigger than the bells we are speaking of here. It would be safe to bet the subject bell in this thread will most likely fail further when heated and if it does not, dropping it hot in water will do the job.

While cast iron can be hardened and then tempered, it is doubtful that we can do it with the methods we have in our shops. From the manual "Tempering is usually performed at temperatures as high as 950 °C (1,740 °F) for up to 20 hours. The tempering is followed by slow-cooling through the lower critical temperature, over a period that may last from 50 to over 100 hours"

 

[wow]

Well, Jim, I am learning a lot here. I was always taught that you just need to get it red hot and drop it in cold water. That’s how I have always done it to make small click springs springier.
?

 

[Jim DuBois]

Well, Jim, I am learning a lot here. I was always taught that you just need to get it red hot and drop it in cold water. That’s how I have always done it to make small click springs springier.
?

cast iron is more than a bit different than the iron and steel we normally deal with. Look it up and draw your own conclusions.

And heating something red hot and dropping it in water is not tempering, it is "hardening" Tempering follows hardening to specific temperatures based on the alloys being heat treated. Ferrous metals following hardening are often very brittle and need tempering to make the surface useful for its intended purposes.

Read more at https://dl.asminternational.org/han...Tempering-of-Steels-1?redirectedFrom=fulltext

 

[wow]

Here is a short video of what I’m dealing with.

 

[Raymond101]

Wow from your photos the bell has flaked on the surface.
Before going into heating and retempering. Polish the inside & out with a fine round drimel Polish ball .
Fix the bell on a long screw and rotate the bell in a slow drill/ lathe.
Polish from outer edge inwards .
And the same on the outside.
You can tap the bell as you go .
If better . U can tune to the desired pitch clean it first. If it still goes thud it's cracked or yo have the fasten screw too tight . A leather washer will improve any bell ..
Raymond
The bell in video the top bolt is not correct. Mount on a leather washer. Top & bottom of the thread . & polish it. It will ring like a bell . If not cracked.

 

[wisty]

Bells are normally tuned by machining the inside in specific places to get the tones and overtones needed. An example

But for proper bells you do need some serious kit

This one does bells up to 2 tons

 

[Raymond101]

I don't think that WOW's bell is that heavy.
Small bell can be tuned in several ways.
Cleaning. If made of steel can be planished with a small ball pain hammer on a sand bed .
There is a difference between a clock bell & church bell
Ie church bells are made of brass/bronze.
Wow's bell is cast waked out of a press .

 

[TEACLOCKS]

Take the bell off the clock and see if it will ring.
Hang it at the center.

 

[Willie X]

I don't think that hammer action is anywhere near what it's suposed to be. Is the hammer head solid steel?

I know it was mentioned but did you smack it (on the edge) with a 2 ounce jewelers hammer?

Willie X

 

[wow]

Take the bell off the clock and see if it will ring.
Hang it at the center.

I did that, Tea. I polished it and put leather below it and above it. Still dead. I have examined for hairline cracks and found none. I have made a contact and waiting to hear from a friend who has a friend who has a forge. Last resort before simply replacing it. I’m not stubborn??

 

[wow]

Other bells I have work great on the post. It’s the bell. Will report back.

I don't think that hammer action is anywhere near what it's suposed to be. Is the hammer head solid steel?

I know it was mentioned but did you smack it (on the edge) with a 2 ounce jewelers hammer?

Willie X

 

[novicetimekeeper]

If you have any tonic water, that fluoresces under UV.

 

[novicetimekeeper]

or maybe just replace the bell with a good one? They are not expensive, they are around, and it will cost far more to mess with the failed bell than it will cost to replace it.

View attachment 765151

Have you got one 3" diameter and 1.25" tall? I have a need for my new 5" hooded dial

 

[wow]

Have you got one 3" diameter and 1.25" tall? I have a need for my new 5" hooded dial

I may have that bell. If so, you are welcome to it. I’ll check tomorrow. Also, I do have an ultraviolet light and I’ll go get some tonic water and try it. I’ll let you know tomorrow.

 

[Jim DuBois]

Have you got one 3" diameter and 1.25" tall? I have a need for my new 5" hooded dial

Novice, I don't have anything quite that size. This is as close as I can come. A bit over 3" dia and too short. The good news about it is it is cast bell metal, not cast iron like many American bells are made of.

 

[Willie X]

wow,
You may be able to slip that bell over the jaws of a vise and open the jaws a bit to spread the bell. This should make the crack visible, or break it completely.
Willie

 

[gvasale]

Well, to muddy up the water...I work for a company that heat treats metals. Plenty of cast iron runs through here. Stress relieving or annealing are the usual processes for cast iron. I have never seen it water quenched or oil quenched. Temperature for annealing I think runs in the 1400° range, but I don't run those furnaces.
Temperature to temper steel has a range from perhaps 500° to 700°, but I don't do that either.

My job is to fill and empty baskets with parts, sandblast and paint parts for nitriding. And sometimes a few other things.

 

[R. Croswell]

wow,
You may be able to slip that bell over the jaws of a vise and open the jaws a bit to spread the bell. This should make the crack visible, or break it completely.
Willie

Cast iron doesn't like being bent. There is gray cast iron and white cast iron. My guess is that clock bell was probably cast from some pretty trashy scrap stock.

 

[Bernhard J.]

I’m not stubborn??

The bell apparently is stubborn

 

[Raymond101]

Wow if you are going to have it retempered when it's heated to 600 deg
It must not be quench in water . If it's cast iron or cast alloy . It will just shatter into many peices.
It's a really exciting to watch at a distance.
From the video it sounds that the metal has crystallized. And nothing will make it change back. Without melting it down completely and re molding it . . Ie RIP.