13 replies to this topic

[TimB]

Forgive the simplicity of my question, but just in case there may be some wisdom available that I can use...

Occationaly, once in a while, I miss the red target with my 3# cross pien and hit the anvil, which causes the hammer to rebound at great velocity toward my face. So far I have controlled it in time, and not whacked myself, but it catches me by suprise every time I do it, and I dread the day I react too slow and make the connection. I use a mild steel, homemade anvil, knuckle height, and was wondering if a real anvil responds that way with such dramatic rebound, or if there's other bad habits this may be indicative of.

[Fe-Wood]

All I can say is SLOW DOWN! If your hitting that hard and missing, you need to slow down the pace until you get GOOD hits every time! Watch Brian B's one heat tong video and you will see what I mean. He uses a very measured and accurate rhythm and lets the hammer do the work. It took me a long time to realize its not how many times you hit it, its how few and how well you hit it that counts. My 2 cents

[John B]

TimB, on 12 March 2010 - 02:37 AM, said:

Forgive the simplicity of my question, but just in case there may be some wisdom available that I can use...

Occationaly, once in a while, I miss the red target with my 3# cross pien and hit the anvil, which causes the hammer to rebound at great velocity toward my face. So far I have controlled it in time, and not whacked myself, but it catches me by suprise every time I do it, and I dread the day I react too slow and make the connection. I use a mild steel, homemade anvil, knuckle height, and was wondering if a real anvil responds that way with such dramatic rebound, or if there's other bad habits this may be indicative of.

Check you stance, If you get a rebound, it should go over your shoulder, not to your head, Just turn away slightly,

Try to watch an experienced 'smith, but don't concentrate on what they are hitting, look at their position relative to the anvil,their stance, spread of the feet, the arm and wrist action, the grip, how they control the blows, the type of blows, their general attitude

Try different methods incorporating what you have seen, and assess how it works for you, then develop your own style

[CurlyGeorge]

Tim, Your anvil isn't the problem. A regular anvil will also send a hammer back up just as fast. Like was said above, slow down on the number of hits until you learn better hammer control and change your stance. Go to some demos and watch other smiths and/or watch some of the videos that some of the guys have posted on IFI. Don't be "gun shy". Just concentrate on the basics until you get them down. Keep on hammering and good luck.

[NRunals]

John B's advice about watching an experienced smith work is really good. When I first started out my elbow would get really sore, so I watched a bunch of videos of talented/experienced smiths and realized what I was doing wrong. Like he says make sure to look at their body position.

[thecelticforge]

Also, I have found that my "accidents" almost always happen when I am sick or tired. I have not yet dared try forging drunk, but, that I know better to do.

[ThomasPowers]

Why is your face so close? Should your anvil be higher so you don't "lean over" as much?

And a hardened face anvil is *much* worse in the rebound department---it will send it back faster and higher!

[Glenn]

The proper term for the time interval from the hammer fact to the forehead is a nadasecond.

*Nadasecond, somewhere between instantaneous and too small to measure. The time it takes for a hammer missing the metal and hitting the anvil to travel the distance between the anvil and your forehead. In many cases a nadasecond is less then the reaction time of the fellow holding the hammer, resulting in the hammer hitting him in the head.

Proper anvil height is confirmed by putting a piece of wood on the anvil face and observing the hammer marks. Crescent at 12 o'clock means the anvil is too low, crescent at 6 o'clock means the anvil is too high, crescents at 3 and 9 o'clock mean the anvil is not level or the hammer is held at an angle.

Stand at the anvil with the hammer resting on the target point of the work. Now move to one side or the other until the shoulder, elbow, wrist, and hammer (hammer handle and hammer head) are all in one plane (straight line). The rebound of the hammer will follow this straight line when it launches from the anvil. Notice that your head is not in this line of travel, your vision is not blocked by the hammer, and you can actually see when and where the hammer strikes the metal.

Another reference about planting cross peens in foreheads can be found here.

[TimB]

ThomasPowers, on 12 March 2010 - 01:16 PM, said:

Why is your face so close? Should your anvil be higher so you don't "lean over" as much?

Actually, I'm not leaning over at all, but the question itself suggests to me that you lock your elbow at the end of your swing??? Not that the elbow would be hyper extended, but that the muscle tension of the triceps would still be engaged in follow through at the moment of impact, requiring the wrist to absorb any rebound?

One theme I'm hearing though too, is body position relative to the anvil. Should the hammer fall on the anvil directly in front of my belt buckle, or directly in front of the hip (or where the hand would be if it was hanging limp from my shoulder)?

Edit: Ok, read further on the subject and I'm thinking I get it. Thanks guys

[Frosty]

Okay, I have a couple bits to add so I'll take em one at a time.

First is called the plane of rotation and why you should stay out of them. The streak of mud on a bicyclist's back is a perfect example, the mud being slung off the tire will fly outwards in the plane of rotation. A hammer rebounding off an anvil from a missed blow will travel in the plane of rotation defined by your swing. This is why you should learn to swing the hammer out of line with your head!

As has been said, a hardened anvil will impart greater rebound energy to the hammer making it faster and more dangerous.

You're encountering what happens when you add power to a system. The more power in a system the more critical and the more difficult control become. For a gross example consider a golf cart, about 4-5HP and no problem controlling it at all. Right? Compare it to a good old fashioned hopped up muscle car sporting about 500 ponies, keeping THAT under control can be a serious challenge. No?

So, those are the reasons to slow down, use a lighter hammer and practice till you have good control. I'm just now regaining some of my former control at the anvil as I recover from the brain injuries I survived last September. Happily I'm getting em back faster than I deserve but I'm still not as good as I was just a few months ago.

In response to your last question. NO! Never lock your elbow, wrist or any other body part in contact with a hammer on an anvil! Do NOT make any part of your anatomy absorb the impact. Hole the hammer is a loose grip, just tight enough it doesn't fly off on it's own. (See plane of rotation above!)I use what I call a "fencer's grip" on my hammers, holding the slab handles between my thumb and index(?) finger. The hammer pivots in my hand till just before impact when I give my fist a quick brief clench bringing the handle and hammer into a more common position with my hand. This does a couple things: First it greatly increases the power in my blows by adding a 4th joint, each joint in your arm, and hand is a force multiplier so adding one multiplies the energy you put into the hammer. The second is the loose grip does NOT transmit impact energies back into my hand and saves me fatigue and injuries.

Frosty the Lucky.

[blazerbud]

TimB, on 12 March 2010 - 08:31 PM, said:

Actually, I'm not leaning over at all, but the question itself suggests to me that you lock your elbow at the end of your swing??? Not that the elbow would be hyper extended, but that the muscle tension of the triceps would still be engaged in follow through at the moment of impact, requiring the wrist to absorb any rebound?

One theme I'm hearing though too, is body position relative to the anvil. Should the hammer fall on the anvil directly in front of my belt buckle, or directly in front of the hip (or where the hand would be if it was hanging limp from my shoulder)?

Edit: Ok, read further on the subject and I'm thinking I get it. Thanks guys

No, you don't want your arm to be trying to hold down the hammer at the end of the blow. You never want any body part absorbing the energy, you want to transfer all energy into the work and make your life as easy as possible. You are describing the wrong kind of striking. Stricking in the manner in which you describe is similar to how a nail is hammered into wood. There is no rebound and the wood absorbs the shock. However, in forgework, You have to stay loose. Your hammer weighs enough to cause tendon and ligament problems if you are fighting it. You have to allow the hammer to rebound with a steady rythm. Muscles are used to bring the hammer down and very little effort is required to pick it back up if any. And as you are in a rythm, when you want harder hits, make them harder or bring it up further before your down stroke. The steel that you are forging absorbs most of the rebound.

In the case of a mis-hit and a huge rebound. Your arm and hammer should fly back up just as you describe, but the hammer and your arm should not be coming anywhere close to your head or face, unless what you are doing is sighting over your hammer as if it where a gun, which is a no no. Your hammer comes back up to the same point where it started from, so don't start from in front of your face.

You should have the ability to fix improper posture quickly, and develop a feel for where the hammer is. It should become an extension of your body and the face of the hammer should become more accurate than Bruce Li's fist. In which case you are not paying attention to body movement, but only to where you want to touch the hammer face on your work.$

[Ed Steinkirchner]

i have a pair of safety glasses that would show haw even a few ounces of ballpeen could really cause some damage on rebound! you should look at Uri Hofi's hammer technique, it would help with your problem, but i think it was in the blueprints it might be found somewhere else though. hope you get it figured out.
Ed Steinkirchner

[Phil Krankowski]

There is a DVD.

http://www.iforgeiro...14329-hofi-dvd/

Phil

[Fe-Wood]

Here is a link to a you tub clip-