Muffling a ringing anvil

Jewelry Discussion
1

Here’s a question for you metalsmiths. In my forging class, we muffle
the ringing produced by working on the anvil by attaching a strong
magnet on the side of the anvil near where you are hammering. It
really really works, but I can’t figure out why. Is the magnetic
field preventing the metal atoms from vibrating and producing sound?
Or is something else going on?

Thanks!
Emie Stewart

2

Nope it is just that the magnet is loosely coupled to the anvil and
it is like putting your hand on a ringing bell, the energy of the
vibrating surface is transferred to the coupled item which acts to
dampen the vibration.

3

Hi Emie;

In my forging class, we muffle the ringing produced by working on
the anvil by attaching a strong magnet on the side of the anvil

I’ve seen this done before. I doubt it has anything to do with
magnetism. As you know, if you have a crack in a bell, it won’t ring,
at least not well. With the cracked bell, the vibration of the two
sides of the crack hitting each other sets up a counter vibration
that deadens the bell. Same happens with the magnet, which makes a
less than complete contact with the anvil, as the magnet vibrates
against the side of the anvil, setting up another frequency of
vibration. I know someone with a better knowlege of physics could
explain this better, and I hope they will.

David L. Huffman

4 
In my forging class, we muffle the ringing produced by working on
the anvil by attaching a strong magnet on the side of the anvil
near where you are hammering. It really really works, but I can't
figure out why. Is the magnetic field preventing the metal atoms
from vibrating and producing sound? Or is something else going on?

An interesting tip. I never heard of this, and will have to give it
a try. In a retail shop forging a shank is often not appreciated by
the staff be cause of the penetrating sound.

5 
Is the magnetic field preventing the metal atoms from vibrating and
producing sound? Or is something else going on?

No, planet Earth is the biggest magnet that we are attached to; and
it cannot stop atoms vibrations. The ringing of an anvil has to do
with acoustic wave phenomena.

When hammer strikes an anvil, it sets up an acoustic wave, which
travels up and down along axis of symmetry of the anvil, very
similar to a guitar strings (or any other string instrument). By
attaching a magnet, you creating an acoustic wave trap. Because
magnet connection with the anvil is loose, the wave dissipates a lot
of energy on crossing from anvil to magnet. The magnet becomes an
acoustic dampener.

Another thing that is going on is because mass of the magnet is very
small compared to mass of the anvil, the magnet will vibrate at
frequency of anvil times mass ratio. if mass of anvil is 100 times of
mass of magnet and anvil vibrates at 2000 Hz, the magnet frequency
will be 2000 * 100 = 200000 Hz, which is way above human hearing
range.

leonid surpin

6

Yesterday I did an experiment here at the shop, attaching different
size magnets to the heavy ring mandrels, and then forging ring
shanks. We noticed no reduction or even slight changes in the
"ringing". Maybe such noise reduction is only possible when doing
this with much heavier anvils, but it did not have any effect at all
on the mandrels that get the most use here, and generate the most
complaints from sale staff!

7

You can stop a ringing anvil by sticking a wad of soft wax or
plasticine clay under the horn…

Andy

8 
Is the magnetic field preventing the metal atoms

I guess I’d heard about this long ago… But you know how you go
out looking for something, and you find somthing else…

http://www.iforgeiron.com/

For all you metal pounders and would be pounders out there…

9

I have encased my anvil in a block of 2x4’s with plywood-and-screws
around that. The latter are extremely strong and so far it holds up
well. Since the wood comes right up against the metal surface of the
anvil, the sound is muffled. It is designed for dropping a 40 pound
metal weight onto the anvil to smash stones in the backyard.

Maybe somebody can tell me how to solve the sound problem when I set
up a ball mill with jaw crusher and cone crusher in the basement,
haha.

10 
Yesterday I did an experiment here at the shop, attaching
different size magnets to the heavy ring mandrels, and then forging
ring shanks. We noticed no reduction or even slight changes in the
"ringing".

Since mandrels are held by hand, they are already muffed. The source
of noise is bench, things on bench, and etc. Ringing means just that

  • ringing!

Leonid Surpin

11

Blacksmiths will sometimes loop a section of steel chain around the
waist of their anvil to muffle the ringing, but the lower
frequencies are still there to be endured.

J Collier
Metalsmith

12

Setting an anvil on a sand base will stop it from ringing. Here’s
what I did with my 125# blacksmith anvil.

I started with an old water pressure tank, 16" dia., cut in half so
it was 22" tall.

Filled it most of the way with sand.

Formed a frame that was the shape of the base of the anvil out of
steel stock 3/16" thick x 4" wide (these dimesions are not critical,
it’s just what I had on hand. This frame keeps the anvil from
shifting on the sand.

Buried the frame in the center of the sand so the top was about 1
1/2" below the top of the tank.

Added sand to the inside of the frame so it was 1" from the top. Set
the anvil in the frame and added sand around the frame level with
top of frame.

Hit anvil - no ring.

13

A GOOD magnet stuck to the bottom of the tail or side of anvil will
also quiet it down.

Bill Roberts