"Baron" wrote in message
news:4f5a6cc6$0$17348$882e7ee2@usenet-

stuff snipped

I want to point out that most face shields are NOT designed for
serious
impact. They are intended to be worn over safety glasses. They can
handle
light to moderate impact but, as one poster reported, the whole shield
flew
off his head when impacted. If the trajectory of the wood was different,
there might have been a more serious result.

All excellent points. It's probably important to remember that for most
people I know, (and is seems at least a few posters here) it's wearing
nothing at all or foolishly depending on regular eyeglasses. A face shield
was a big step up for me. Based on what I read, I'm not the only one who
took some "convincing" to go out and get one. Part of the great value of
newsgroups like AHR is to speed the spread of good ideas. I'll bet at least
a few posters have face shields on the list for the next hardware store
visit. (-:

I remember working with a metal shaper (marked "War Department") in high
school. It was a huge, belt driven ram sort of device that pushes a tool
bit over the metal stock, moving slightly each time. The ram head was sort
of the size and shape of the creature's head in the Aliens movies.

The normal bite of each stroke way less than 1/8" but if you failed to
securely tighten the height adjustment, the shaper head would take one
properly sized cut when the ram moved forward. Then, the ram pulled back
and the stock table jogged to the left to expose new material to cut.
Normally, the tool bit and holder would clear the work on the back stroke,
the table would shift and the ram and tool bit would come forward at the
same height to take another "slice."

If the height adjustment was too loose, it would often hold for the first
stroke, but then the vibration of the backstroke would loosen the whole tool
bit assembly and it would drop down to the bottom stop. Way below the
surface of the work and the vise that held it. Then, the whole ram head
swing forward and would smash into the vise table about two or three inches
below where it should be. It rang like a bell, the floor shook, the belt
stopped and people jumped right out of their skins. No face shield, just
pretty crappy over-the glasses, elastic band goggles.

That huge ram sounded just like a bad car crash when it hit the table hard.
No one was ever hurt that I know of, but it was the event of the day in
metalworking. IIRC (and IMNRC - this was 50 years ago) most metal shop
injuries came about by guys screwing around with the long coils of (I used
to know this word) metal that came off the lathes as they cut. They were
hot, they were razor sharp and sometimes if you didn't clear them they would
wrap around the spinning work and whip you but good. Foundry on the other
hand was famous for foot injuries (those sand filled molds are HEAVY!) and
hernias.

For whatever reason, they stopped actually casting things in the green sands
of the 8th floor foundry with its huge glass ceiling, the panels operated
from 40 feet below by wheels and chains. I believe it was built in 1908
when Brooklyn Tech was the center for training in all things industrial. I
heard they stopped pouring metal because kids were making very accurate
castings of guns. I suspect the mere thought of high school boys
jackassing molten metal around in NYC was just too much for the school
adminstrator's hearts. (This was long before it was *forced* to go co-ed.)
AFAIK, they kept teaching foundry for years but without molten metal. Kind
of misses the point!

We had projects that continued through each grade. In four years I learned
to free hand draw a spanner wrench, then make mechanical drawings of it,
then make a wood pattern for it and finally casting the wood pattern in
metal. Then we would machine the rough spanner wrench casting in metal shop
and heat treat it in metallurgy class where we also tested hardeness and
other qualities.

While it was more fun than calculus, most of the shop classes eventually
turned out to be equally useless in my work career. The best part about it
was learning how to take a project from beginning to end. That turned out
to be a useful skill in managing large software projects. That and a book
by what was then Touche-Ross, a big accounting firm. Ever come across a
single book that explains all the inside tricks of a trade? It was a
compendium of everything they had learned putting huge corporate systems
together on mainframes. Ironically, the same problems plague large
mainframe and small PC networked systems.

--
Bobby G.