Why did the Hammer Bend?

Shortly after the murder as part of investigating the type of wounds the suspected hammer may have inflicted – with regards to sizes and shapes – Captain Frans Maritz conducted some tests on pig’s heads.

After a few blows, which Captain Jannie Bester administered, the suspected hammer bent. The defence exploited this as proof that the hammer would not have been strong enough to have been used in the attack on Inge. Is this a fair deduction?

The hammer bent when it was used to strike a pig’s head with full force, whilst the head lay on an immovable steel table. The blow (with a straight down action line) was planted onto a very thick part of the pig’s skull.

Also, the force acting on a hammer is inversely proportional to the distance over which the hammer travels from its initial impact velocity to zero. Thus, assuming it takes a hammer 3 mm to stop on a pig’s head and 9 mm on the victim’s head, then the force acting on the hammer hitting the pig’s head is 3 times more. The force acting on a hammer hitting a pig’s head was in all probability much higher than it would have been hitting the victim’s head, which was resting on a cushion, received most blows to its sides, and which could rotate and move around on impact.

(Please note, the structure of the hammer did not bend or break, only a part of the bottle opener side bent inward.)

Although a pig’s head is generally assumed to be suitable for such testing, it is a fact that the skull of a pig is more robust and thicker. Because its head hangs and is not upright like a human’s, they also have more muscles running onto the skull. It is safe to assume that a pig skull will offer more resistance to a hammer blow than a similar strength blow on a human’s head.

The above clip is a short extract from the tests, and shows the type of blows administered. As can be seen, extremely hard blows were administered in a straight down action line onto a very thick part of the skull. The pig’s head was resting on an immoveable steel table and held in position by someone. The head could not move around on impact.

Inge’s head was resting on a cushion. During the first few blows it may have been in the air, able to move on impact.

Even if we consider everything being equal (strength of blows and skull properties) the blows on the pig’s skull would have exerted more force and resulting strain on the hammer, since the head could not absorb the load as well as Inge’s head on the cushion did. Inge’s head could press down into the cushion and considering that most blows were inflicted on the side of the head, it could rotate around on impact, dissipating much of the load.

The fact that the hammer bent on a pig’s skull certainly is no proof that the hammer would have bent on Inge’s head as well.

No blood on the hammer?