Blades that ring or sing or chime - why?

[Hurrul]

Greetings -

I am not a maker, but my questions seem to need the knowledge of a knife maker. I could not find anything searching around BF or the net - I don't know the proper language to search with and likely that is limiting my effectiveness.

Why do some blades have an audible tone when used or when struck with a finger nail?

Not all my blades produce a ringing or chiming quality, but a handful do:

Several Japanese kitchen knives made by: 3 Takada (all laminate steel, stainless clad with non stainless core), Kanahide (mono steel, stainless) - these are a higher hardness around 61+ RC or so.

But, I have a larger chopper type blade in 5160 that has a noticeable tone, yet hardened around 57+ RC or so. However, I have other larger 5160 chopper blades that have no audible ring.

Does this tonal characteristic come from the heat treat/quench/temper process? or from another part of the knife construction? like the handle install if the handle has had weight reduction type work like drilled holes or voids cut into it?

Do only certain steels do this when heat treated properly?

Or a combination of details - heat treatment process, type of primary grind, steel stock thickness, handle work, steel type....?

Is this a sign of proper heat treatment processes? a sign of hardness?

Thank you for reading and for your time.

Scott

 

[Randy3000]

I am pretty sure it is just harmonics and standing wave vibrations. Like a tuning fork. I suppose any solid uniform piece of metal has fundamental frequencies it will sing at. Whenever i walk into my work building i can hit the handrail a few times with my hand and get it going and people 30 feet away can hear the singing.

 

[Hurrul]

I am pretty sure it is just harmonics and standing wave vibrations. Like a tuning fork. I suppose any solid uniform piece of metal has fundamental frequencies it will sing at. Whenever i walk into my work building i can hit the handrail a few times with my hand and get it going and people 30 feet away can hear the singing.

Thanks R Randy3000 .

 

[skillgannon]

I have noticed that it does it when the blade and handles are well bonded.

 

[daizee]

It also depends on where you're holding it vs. where you're striking it. That affects the harmonics too.

 

[Stacy E. Apelt - Bladesmith]

When I was a kid, all coins except pennies and nickels were silver. You could filip one in the air with your thumb and hear it ring. Same for spinning it on a tabletop. When they switched to clad coins, the ring went away.

 

[mike-E]

When I was a kid, all coins except pennies and nickels were silver. You could filip one in the air with your thumb and hear it ring. Same for spinning it on a tabletop. When they switched to clad coins, the ring went away.

Every once in a blue moon I'll get handed change and by just the jingling sound I'll know there is a silver coin in the bunch.