[TheForge] Fatal acccident

[jerry Frost]

Just do the arithmetic Bruce. Figure a 9" buffing wheel on a 3,450 RPM
motor. My math might be off I'm doing it in my head but I get about 8,130
feet per second surface speed, that's faster than most rifle bullets. What
part of a human chest is going to stop that? How much momentum does a 6 oz.
knife blade have moving at 8,130 ft/sec? I'm thinking it'd defeat plate
armor if it hit end first, either end. Don't think of it as a "thrown"
blade, think of it as one fired out of a gun.

People have been trying to figure out how to make a guard to prevent objects
from getting caught and thrown from wire wheels and buffers for centuries,
well better than one century anyway, nobody has come up with anything that
isn't more dangerous than no guard at all.

When you say prevent it from traveling 360* you're thinking 180* and that is
right back at you. The wheel covers almost guarantee anything that won't
stall the motor WILL come directly back at you. Usually aimed at your waste
but it doesn't make a whole lot of difference where something going that
fast hits you it's going to take it's pound of flesh if not your life.

There is only ONE thing I know of that CAN make wire wheels and buffs
reasonably safe and that's operator technique. STAY OUT OF THE PLANE OF
ROTATION! You guys have probably read me saying this till you're sick of it
but that's it, as safe as you can be using wheels. Heck grinders catch
things once in a while and throw them at the operator. Just don't be in the
way WHEN it happens. Learn to operate grinders, wire brushes, buffers, etc.
from the side, NEVER in front of the wheel. You've seen water or mud slung
off a bike wheel? THAT'S the plane of rotation just stand to the side or the
steel version of water spray might come to visit.

Something else for you blade guys to think about. You all know you can build
stresses in the blade grinding, you normalize or even anneal after grinding
before hardening and tempering to relieve stresses or risk a failure be it
outright breaking or cracking. Buffing imparts heat and high frequency
vibration to the steel and if there is a potential crack buffing can cause
it to appear. Nothing like a crack to grab a buffing wheel even if you're
doing everything right.

If you're not at least a LITTLE afraid of wire and buffing wheels you're not
paying attention or just not aware of what you're doing. You just can't let
fear effect how you operate machinery or it WILL get you. "You can't fear
the machine but you MUST respect it." My Father said that or a version so
many times I got sick of hearing it but no truer words were ever spoken.

I gotta sign off now, this topic is a THING of mine.

Jer

-----Original Message-----
From: TheForge [mailto:theforge-bounces at mailman.qth.net] On Behalf Of Bruce
.
Sent: Monday, November 17, 2014 11:24 AM
To: Blacksmithing List Sponsored by ABANA
Subject: Re: [TheForge] Fatal acccident

I was wondering about that.  A blade would have to be traveling upwards to
pass between the ribs and into the heart.

I could understand how a femoral artery could be severed by a thrown blade,
but the heart was a puzzler.

Maybe ABA or ABANA (which, of course, would translate to some individual
bladesmith) could come up with recommended practices for mounting and using
a buffer?  (I'd do it if it were within my ken.)  It might save a life.

Bruce
NJ

On Mon, Nov 17, 2014 at 3:02 PM, barry myers <blmyers647 at gmail.com> wrote:

> The problem with a lot of buffers is the mounting.  People mount them 
> back on the bench so that when the blade is ripped from your hand, it 
> strikes the bench and rebounds into you.  They need to be mounted so 
> that the wheel is proud from the bench (over air) and then put a 
> wooden box below to catch the blade.
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