Reading through an couple month's-old Popular Mechanics magazine this morning, I saw a titanium hammer for which they did a little highlight blurb.

They claimed that because it was lighter, one could swing it faster, thus providing greater striking force.

My sketchy memory of the precise terminology of science/physics tells me that mass X velocity = force.

So doesn't that make a lighter hammer moving at a faster speed strike with a force equal to that of a heavier hammer at a slower speed, assuming that the arm swinging the hammers has a constant "strength"?

A car weighing 2000 lbs hitting a wall at 60 mph will hit with the same force as a car weighing 4000 lbs hitting a wall at 30 mph, no?

Since the speed at which the hammer can swing is determined by the strength of the arm swinging it, the arm strength is a constant. Thus a lighter hammer swinging faster has the same force as a heavier hammer swinging slower, right?

PM is a pretty good magazine, but it is a shame that misinterpretations of physical laws make their way into print in this manner.

I kinda think the writer of the article/blurb just took what the description of the tool on the tools website said and repeated it without identifying the innacuracy of the statement. The website said essentially the same thing, just phrased a little differently.

Is my memory/understanding of the laws of physics correct or is the titanium hammer really more "powerful"??

The site was Framing_Hammer_Titanium

"Lightweight TiTech Titanium swings faster for greater power at point of impact with less stress and arm fatigue. Steel caps can be changed for versitility and longer hammer life. Replacement caps come with shock absorbing pad, free floating hex pin and hex key."

 

Actually.....it's Mass x Velocity*squared*, so the speed is more important that you might think.
Lighter weight sure has to help your 'tennis elbow' by the end of the day. I swung a 32oz. Estwing for years as a kid.

I've seen a lot of titanium hammers on job sites recently. Some guys swear by them, others swear at them.

The Stiletto and the Deathstick seem to be the ones.

 

I think PM & ArdWrkn are right, a higher speed of a lightweight striking tool will yield more
force. I've seen this explained on a woodheating list I'm on where people sometimes talk
about methods of manually splitting firewood, here's a cut-n-paste I just dug out of the
archives:

 

Thank you for the clarification ctubutis.

You're correct on the formula..... I should have written it as X/2.

 

I've always though that a heavier hammer hits harder, but then I don't do much in the way of framing.

 

Guess I've been going about this all wrong - using a 20 oz framing hammer for big nails, and a 12 oz hammer for finish nails. So, all I had to do was swing the 12 oz faster and i could drive 16d nails with it. Sure didn't know that!

Anyway, while on the subject, when I use a sledge (BIG) hammer, say breaking up concrete, I don't swing it. I just lift it high and let it fall. Must be doing that wrong too.

 

cool.
Good to know that a magazine with the rep of PM wasn't blowing smoke.

 

Wow, this is a messed up thread, though ctubutis touched on a few good points.

F=ma F is force, m is mass, a is acceleration
KE=(mv^2)/2 KE is kinetic energy, m is mass, v is velocity

The force delivered is related to the impulse--which is the time of deceleration during impact, which will result in a high (negative) value of a (deceleration is negative acceleration).

As to the car example, a 2000 lb car going 60 MPH crashing into a wall will deliver more ENERGY to the wall than a car going 30 MPH that weighs 4000 lb. Force is totally unknown, as that would depends on the crumple zones of the vehicles and how much the wall gives way, but could be figured out with experimentation or more info. Momentum is the same for both vehicles, as momentum is mass x velocity.

As for whether or not to use a heavy or light hammers, let me ask you this: why would baseball players cork their bats?

I also know a builder who is in his 50's and has always used a ~13 oz hammer to frame his houses--won't use a larger hammer or a pneumatic nailer.

Jason

 

Would be interesting to see him drive some of those 6" spiral pole barn nails . the kind that go paaannng - pinnnnng -pinng -ping each time you hit it. (Just make sure you hit it square, because you sure as He$$ can't pull it out).

 

It's a ploy to sell $150 hammers.

Try and pound a steel stake into the ground (work) with a 12OZ Titanium hammer. It'll take You 30-40 swings to get it down 10". Now, arm Yourself with a 6 LB hammer. It'll take You 8-10 swings to do the same work.

Which is more fatiguing?

That is debatable.

 

There's not much debate to the three laws of Newtonian physics.

You're not delivering the swing of your arm to the nail but the kinetic energy imparted by 1/2 the mass and velocity of the head of the hammer.

A 16d sinker is not even close to 13oz...

If the 'steel stake' weighs more than the entire hammer it's like a car trying to move a bridge abutment.

 

Just found this thread by accident. Interesting. I've framed houses for almost ten years. I got a titanium hammer a couple of years ago. Started with the wood handled stiletto but kept breaking the handle. Mostly use it for siding and stuff now. I then bought the solid titanium one (the t-bone), what an awesome hammer. I tried all different makes and weights of hammers over the years nothing compares. I can drive nails just as well or better with the titanium hammer. My elbow loves it. Take it from someone in the business it works. Its no gimmick. Most guys I know who tell you its no better than their 22 oz estwing are just to cheap to buy one. If you do alot of framing its worth every penny.

Just on a side note, I think that the length of the handle has an effect on head speed of the hammer. Longer = higher speed. On the six pound sledge example mentioned earlier if you cut the handle shorter it would take you way more swings.

 

So what does that hammer weigh? A 22 oz titanium hammer will act just like a 22 oz steel hammer......

 

15oz....
Amazon.com: Stiletto TB15MC TiBone 15-Ounce Titanium Milled-Face Hammer: Home Improvement

 

I think this might be one of the 'devil is in the details ' issues.

Yes, force is related to velocity squared. But, you can't make a hammer too light, or you can't swing it fast enough. (This came to me right after somebody posted it)

I'm also wondering about rebound. The force works on both sides. If the hammer is too light, it will hit hard, but the bounce back force will also be large. Might actually cause the hammer to rebound before it moved the nail very far.

The titanium hammer might be a good balance - 15 oz is not exactly light. Also, it's presumably quite strong, so the shaft doesn't bend backwards on impact.