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Hammer technique - physiology ?


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The attached photos show hammer handles with a saw kerf in the upper third. This allows the hammer handle to flex, absorbing the shock of the blow. Before attaching the head, a gasket sheet from the auto store is inserted within the kerf through the head and for one inch of the exposed handle, in order to keep the kerf from closing. One can drill a small hole at the base of the kerf to retard any splitting of the wood. The handle, up to the head, is soaked in linseed oil for one week in order to add more flexibility.

One can retrofit a hammer with handle by using a cut-off blade on an angle grinder to create the kerf.

It was Beau Hickory who presented this handle adaptation at the 1980 ABANA Conference. Francis Whitaker also claimed provenance.

I shall be composing an article on this handle for ABANA Hammer's Blow.

Hammer Saw Kerf - 1.jpg

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On 12/28/2019 at 7:17 AM, miro said:

hat lead me to my question:

Is there a good description of good arm / body technique / stance that will prevent injury from repetitive actions? Are there execises that help build up strength in muscles,/ tendons/ ligaments when I'm not at the  forge?

Hi Miro.

The answer to your question is well addressed by Jenny (Jlpservices)  in her answer above. 

Most important thing to remember is that we are all different. Hight, weight, fitness level, age all play a role and what works for me will not necessarily work for you. 

In my days of gymnastics competition we observed that those that started training and were naturally built like a tank, did much worse than those who had a slim complection and worked up to the fitness level required through specific training. 

Forging is an uneven and anaerobic exercise. Repetitive movement, shock and vibration add to potential injury. 

Small hammer and small stock to begin with, and as far as exercise, I keep in shape with a bar and rings hanging under my veranda. My neighbours think I am a lunatic hanging upside down at age 70, but ... who cares right? :)

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Marc, that really is the way to go.  Few understand the use it or lose it kind of detail.  

I thought I was immune to it. 13 years off has shown me different.  I'm 3 years out of retirement and I'm still having to get back in shape..  I start getting there by the end of demo season and just starting to feel I am getting back some forging ability and prowess, but then I go back to forging once a month and it fades away again. 

I can explain it. I can even show someone how to do it..  But it is not at a professional blacksmith level.  New year is coming though. :)

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Here you go, 

69F08CF0-C4CA-443B-9408-B15BA137DED3.jpeg

6F0C6D62-E1AE-45F1-9452-F13D3A9CA124.jpeg

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This is basically the same tried and true way of measuring axe handles. Hand or hatchet handles from palm to inner elbow, 3/4 or forest axe from palm to armpit and felling axes from palm of hand to center of chest with arm splayed out. Feeling axes and full sledge handles (those for very heavy work on low anvils) should be the same.

now I will admit that the little sledge gets used a lot for non smithing things like driving form stakes and such as it’s very handy.  

As you can see I have fairly long arms

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thanks Charles..  It's funny.. I thought your sledge handles lengths would be right in that range.. I would think for most forging people that length is the length.. 

I went and measured my old sledge hammer handles yesterday and they were all between 20 and 22" From 6lbs up to 18lbs.. 

The general purpose sledge hammers had stock handles and lengths.  but the double faced forging sledges all have the shorter handles. 

Our handle lengths for the rounding handle and my forging handle lengths are pretty close.  I have moved a little bit longer on the forging handles on the lighter hammers. 

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Hammer handle length for one handed forging hammers is one area that the beginner and the occasional blacksmith must keep an eye on. 

In order to move more hot steel it is a temptation to increase handle length. This comes at a cost. During the upstroke, the longer the handle the harder it is on the extensors in the forearm. A short handle Hofi style is easier to turn up with a wrist movement. If the arm is not strong and fit, a longer handle will result in pain.  

Of course this can be overcome by holding the hammer in the center of the handle to allow it to swing/rotate in your hand freely, ergo the advice not to cling to the hammer. But the temptation to grab it by the end of the handle and give it all you have is always there. :)

Best thing for a person starting is to use small hammers on small stock, and avoid striking hammers if you value the integrity of your back. 

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You can always choke up on longer handles, but you can’t move back on shorter ones. Short handles are for driving chisels (thus the short handle on stone masons hammers) wile longer ones are for generating more driving force. A 1-1/2 to 2# hammer with a longer handle is versatile and useful, Smith’s with heavier hammers tend tord shorter handles, but would still use a longer one. Another issue is handle size and shape, a to large handle is harder to hold on to and will exacerbate the death grip. My hand hammers are all about 1x1-1/4” flat sided ovals in crossesction with 1/2 the handle length as usable grip. I usually have 2” give or take sticking out of my hand but for the first few heavy blows I back up all the way and reach for the sky. 

I typically shape shoes with a 2# rounding hammer but generally smith with a set of 3# hammers. I do have 1-1/2-4%# hand hammers...

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Interesting you say that Charles. I used relatively shorter handles on cross peen hammers 2 to 4 lb, slightly longer on 22-28 oz ball peen and recently switched to longer handle and rounding hammer also 2 to 4 pounds. Yes you can go half way on the long handle. I find that going back to short Hofi hammers needs a bit adjusting back to and what seemed to be the way to go, is now an annoyance. For me anyway.

We do change and adapt, but my point was more to the original question of how to avoid injury. Shoulder and forearm strengthening exercises are paramount.

 By the way, I had a 40 years old shoulder injury that did not want to heal. tried physiotherapy, osteopath, acupuncture  and other methods to no avail. Only this year I discovered an exercise physiologist who fixed it in a few month twice a week sessions of active exercises. The key is active as opposed to passively expecting someone else to do it for you :)

I would probably embarrass myself trying to make a horseshoe at the speed you guys do it let alone fit it. 

 

 

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Marc you make good points for a beginner..    Longer handles vs shorter ones..     With this said.. There is nothing wrong with a shorter handle, just as there is nothing wrong with a longer handl.

As I mentioned earlier there is a huge difference between what I can swing comfortably even at my level of shape (which I consider myself out of shape, but can swing the 4lbs all day long 6-8hrs non stop).. but still consider myself not in forging shape and I don't choke up.. 

With this said I do change hammers a bunch for general forge work for what ever hammer will offer me the blow or hammer strike I want.   

The key here is again common sense and do what feels responsive.. 

Again, I think this thread is geared towards beginners so again.. common sense and not moving up in weight or to long in handle length..   

Ok, since this was brought up it is a good point to look at also.. 

handle length as a function of wrist over taxing. Or getting a tired wrist..    A tired wrist is a sure sign the hammer handle is to long and or the hammer is to heavy.   Or both. 

When I move up to the 6lb I have no problem starting out and as I get tired I choke up on it till I get to tired and just switch to the smaller hammer.. the 6lbs hammer is still swung like a regular hammer..  (this would be tough on most peoples wrists).  And goes back to the moving up slowly in hammer size till the hammer is just swung without notice. 

where this changes in how the hammer is  swung is once I get past 6lbs.. then I move the hammer in more of a straight line from the elbow and shoulder and limit the stress on the wrist, nearly punching with the hammer vs swinging it.  Basically or nearly straight up and down vs in an arc.   This allows for a good hit but nearly takes all of the wrist stress out of it.. 

Wrists are pretty small and really unsupported even compared to the elbow or shoulder and increasing leverage through an over weighted hammer or to long a handle which is basically the same thing. 

 

Marc fitting or making a shoe is a specialized task vs general forge work. 

30 years ago, I did not know one farrier that was good at making anything but a shoe..  Now there are many farriers who love to forge for fun so it's a different ball game.. 

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ha ha, your description of one hand swinging a large hammer is spot on. I had to do it a few times and all I had at hand was a 5kg sledge. what is that 10, 11 pounds? Boy was that not the way to go. Ok I smashed what I was doing well and good but ... don't try this at home

I don't get wrist pain, more tennis elbow if I am careless with weight and handle grip ... but you're a spring chicken compared to me :)

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I have several hammers but my main two are a 2.2 lb. cross peen and a 1lb. ball pein. I do the rough/ heavy forging with the cross peen. Then the detail/ finish forging with the smaller one. I haven't measured them, but they both range in the 12" to 14" lengths. I tend to hold them just below the middle of the handle towards the end. If it's small, fine detail, I may choke up a little, but not much. I had one that had a short handle and at first it felt good. But now, I don't like it and I never use it. My preferences are still changing, but I do like a longer handle now. I'm short, so those handles are actually longer than the distance of the head in my hand to my elbow. Since I've hurt my wrist before, I try and keep it loose and relaxed. 

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CGL,

You do not have abandon using your short handle hammer.

Solution,

(drum roll please,  maestro!),

Fashion a new handle that better suits your hammering style.

I.F.I. has numerous threads that discuss making and installing hammer handles.

Regards,

SLAG.

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Charles, I wish I had that full body farriers swing! It's great to watch. SLAG, touche', you are right. I've actually made a couple handles myself. But that hammer sort of got relegated to being handed to someone when they need a hammer for whatever when they can't find theirs. At least it still has a useful life ;)

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It's one of the nice things about producing the videos..  It shows some stuff..   When I am forging for a while.. I mean when I am forging every day.. By the 3rd day I start to migrate into my natural swing rhythm and movement..  My hammer stroke is not from the elbow but from the whole arm and body in a circular, driving the hammer into the metal kind of motion. 

I like Hofi's take on it, but have never been one to implement his swing or lack of.   I also can not use his type of hammer.. I smash my pinky as I have a tendency to work over the anvil and very much inline and close to it. 

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54 minutes ago, jlpservicesinc said:

See your all ready a hammering fool. One of the best forms of conditioning.   Do you switch hands so both will become able to forge with? 

Absolutely I do.  Easier to switch hands than move my whole body to get the right direction.  Left hand has less power but good accuracy.  I build retaining walls and paver patios mostly. No one can set base faster than me so I do it all while running the crew.  We are one of the most recommended hardscape crews in Spokane 

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