dsparks

When I first saw this topic in Fine Woodworking I was tempted to air my experience, but 'lazy' won out.
Now, I would like to add my comments to the 'Hammer Strike' debate.
Whwn I was just going-into-teenager my father worked for a local hauling company, driving large trucks. The money wasn't all that great and so he took advantage of any opportunity to scrounge things that would have been wasted. One of the things he brought home was rough 2x6 and 2x8 lumber that had braced new vehicles in the railroad cars to prevent their moving about. Many of the boards were strapped at the ends to others, held in by spikes. After getting them home it was a job removing the metal strapping & the spikes. One of the ways to remove the spikes was to drive the claws of a hammer under the head of the spikes to get that initial purchase.
I was doing this one day using 2 clawhammers. striking them face to face, when I recieved a rather severe eye injury. I though at first that an end of the strap had flicked up & hit me, but after waiting 3 days in the hallways of the local hospital after x-rays, I was sent to the University of Alberta Hospital where more expert medical was available.
They saw that there was a chip of metal embedded in my retina, and tried to do something about removing it, but the pressure in the injured eye was so great they couldn't penetrate into the eye itself. Considering that this was in the fall of 1957, I was probably lucky they didn't remove the eye.
So I was left with a chunk of steel embedded in my retina for many years. In about 1990 my GP wanted an x-ray of my sinuses because I had several bouts of an infection. When he saw the bright white spot on the x-ray he immediately wanted to see me. After explaining what and why it was, he ordered some sophistocated tests, as the iron leaching into the interior fluid would eventually destroy the retina's capability. Five years later the same tests revealed that there was a noticeable deterioration in the retina's capability, so he sent me to a eye specialist to arrange the surgery. At the same time, that eye was devloping a cataract, so another surgeon joined the fray & both were done at the same time.
The metal chunk had embedded itself in the retina, severing the nerve to about %40 of my vision. The chunk broke up into several particles as she tried to grab it, so she ended up suctioning out a lot of the fluid to get it all, more than half of it. I then had the curious sensation of watching my eye refill itself over about 2 months or so. Only after the level reached above the pupil could I see objects with any clarity.
I still have that chunk of hammer. It was about 0.5mm by 0.3mm by about 0.1mm thick. It had gone completely through the lower white of my eye, through all the gel/fluid in the interior and had lodged itself in the retina at the back of the eye, severing a lot of nerves. It missed the main optic nerve 'bundle' in that eye by about 5mm.
I have always wondered what it's actual velocity was.

dsparks