[TheForge] Re: Little Giant / pulley / rpm / ???

[Mike Spencer]

Bruce wrote:

> You sound disgruntled.

You meh say dat.

> ... "Snow is beautiful!"...

Yes, it is.  I spotted a ruffed grouse doing its courting display,
ruff up, tail feathers spread, only the second time in my life I've
managed to see one of these perfectly camouflaged birds do this. It
was only because of the snow that he was visible.  I feel bad for the
poor, pathetic guy. "Yow!  Hey, ladies!  Time for hanky-panky, time to
nest, start a family!  Here I am!"  Only the snow is still 4' deep
over everything a grouse holds dear except the edible buds on my apple
trees. (Growl)

> I guess I can't blame you for being mildly annoyed by 4 feet of
> snow.

Indeed.  A little spring snow storm is nothing out of the ordinary
here.  But *not* 12" on top of 2 or 3 feet already laying on.

> There on pp 450ff (of the 12th Ed., 1943 -- years before I was
> born!) are formulas for al sorts of springs.

Oh, good. Although my copy is newer (1971), it has 45 pages of stuff
on springs plus more under "shafting" re torsional loads.  So far, I'm
good with f = kx although now I wonder if loads on a LG spring might
qualify as "shock" loads (vs. "static"), accounting for the rather
hefty size of an LG (or similar hammer) spring.

> And you're dating yourself with the MacHinery reference.  I doubt
> anyone under 40 has even heard that one.

Yeah, yeah, well, I'm older than your M'sHbk, so there.  I'm older
than Old Bert Shaw was when he got me interested in smithing in the
first place.  Up until recently, I was fairly hip vs. the "kids": 6
working computers, Linux etc. Now, with no cell phone, no tablet, no
Farcebook or Twitter or gmail or U-tube but still dial-up internet, I
confess that I'm a relic.  And the average age of a tool in my shop
is... what?  Maybe 75 years, all those nice new^h^h^h newish power
tools notwithstanding?

> I will NOT recommend HF anvils for any serious blacksmith.  But
> these are for demos in which a novice might be working -- and
> dinging up the face.

My *very* *first* blow struck at the anvil: I was hanging around Bert
Shaw's shop in Leverett, Mass.  He points at the sledge hammer so I
pick it up.  He pulls something out of the fire, lays it on the anvil
and says, "Hit it".  So I did, only I missed the workpiece completely
and made a ding in the edge of the anvil.  And froze up, like a deer
in the headlights, thinking that I might have to run for my life.  But
Bert say, "Hit it, HIT IT!"  So I did, didn't miss again.

Pretty soon, Bert puts the iron back in the fire, takes his nasty,
twisty little cigar out of his mouth, spits on the floor and says,
"Don't worry if you can't hit twice in the same place.  Some days, I
can't hit *once* in the same place."  I surmise that I've been a
blacksmith ever since. :-)

Post-Script for Bruce:

> ...dead-blow anvil...

I had an argument with one of the instructors at MIT when I was doing
demos there.  Isaac Newton said momentum is conserved.  Who am I to
argue with Newton (genuflect)?  But if you drop, say, a steel ball into
a tub of wet clay, it stops.  There is no motion, thus no v, so no mv.

Makes perfect sense in terms of energy: the energy (whatever that is,
exactly :-) is converted to heat, maybe a little to gravitational
potential energy by pushing some of the clay up, and so on. So I'm
good with conservation of energy because you can have energy that
doesn't depend on velocity.  But my MIT guy just insisted that
momentum is conserved.

How is that dealt with in practical engineering?  Surely you don't do
some gnarly thing with the mass of the earth and a 10 to the minus
bignum change in its velocity.  Or do we just tell Newton (and my MIT
guy) to stuff it?

Just a little distraction for you while you rest up from your
workshop.


- Mike

-- 
Michael Spencer                  Nova Scotia, Canada       .~. 
                                                           /V\ 
mspencer at tallships.ca                                     /( )\
http://home.tallships.ca/mspencer/                        ^^-^^