[TheForge] Another Long rambley YAK

[Bruce Freeman]

Frosty,
 
My math is limited too.  Nobody's isn't!  The trick is to use what math
you know to the greatest advantage.
 
The more math I study, the more I realize that it is not a be-all or
end-all.  In fact, it has only occurred to me in the past decade or so
that we're only taught ABOUT mathematical expressions that someone has
found uses and solutions for.  Mathematicians look for solutions to
expressions nobody has yet to find a use for.  Somehow, what gets swept
under the rug is the vast array of expressions that would be very useful
to solve, but which nobody can solve.
 
Because of these, numerical methods were invented.  As I commented
before, these are methods of cheating.  You set up an expressions, you
find you can't solve it "mathematically", so you find a solution set by
plugging in numbers.  With computers, this is quite practical.  You
don't even have to plug the numbers in randomly - you can use a simplex
(or other) optimization to help choose possibilities, which really
speeds things up.  These are elementary concepts.  If you can understand
basic geometry, you can understand simplex optimization.
 
I repeat:  I'd be proud to reinvent the Scotch Yoke too.  Anyone should
be.  I rediscovered the theorems of Boolean Algebra when I was in high
school.  (They're counterintuitive theorems, BTW.)  I was quite proud of
that.  I wasn't the first - Boole was (I presume) - but I still made the
effort and achieved the end.
 
And your approach to proplems, like pipe mitering, is commendable.  The
other week, a friend had a practical problem "in trigonometry" that he
asked me to help him with.  I solved it using trig, then found neither
of us had a scientific calculator OR trig tables handy.  So I redefined
it as a graphical problem, and he ended up getting his solution that
way.  Hey!  A solution is a solution.  It's not "better" if it comes
from math.
 
The funny part is that when I do have the mathematics to solve a
problem, I still rarely solve it in one try.  I sketch out the geometry
(typically of a mechanism), label lengths and angles, study it, write
out a few equations, get muddled up, throw it out, and redraw it ...
maybe three to eight times.  In the process I sometimes revise the
"nomenclature" (formulas are EASIER with factors like "A, B, and C" than
with factors like "F1, F2, Fmax, and Fmin").  I stumble over things like
I reported before - I just couldn't solve for the intersection of two
circles not both on the same axis.  (Maybe it's not possible?  Who
knows?)  But by dint of repeated trying, I ususally come up with a
solution set, even if I have to use numerical methods.
 
-change of subject-
 
It's funny the perspective we get on the world.  You see weldors
everywhere you go.  Now that I'm associated with blacksmiths, I see a
lot of weldors too.  But I also see where I came from - I NEVER knew any
weldors, and knew nothing about welding.  Even now welding is only a
little tempting to me.  Yes, I could do some nice things with it, but I
can often achieve those ends by other means.
 
I'm reminded of the precept, "If your only tool is a hammer, every
problem looks like a nail."  In this case, we have a large number of
people who can't conceive of building a machine without welding.  No
problem.  Any machine I design could easily be modified to be fabricated
with using welding.  Maybe the result would even be better.  But go look
at a drop hammer or Oliver hammer built mostly of WOOD and tell me that
serious machines must be assembled by welding!
 
But make no mistake - the Grasshopper is a welded fabrication.  True,
when Cameron Stoker built his he did MORE welding than we did, but he
sacrificed some flexibility (to disassemble and repair) that I built in
to the design.  AND the Grasshopper does require at least a drill press
to construct.
 
It's the Weightless Hammer that is not welded.  I can think of only
maybe a dozen places where weldes COULD be used on that, and don't see
that they would produce any better machine than the bolted
construction.
 
The reasons there aren't Grasshoppers (aside from the little brown and
green ones) all over the place are simple:  (1) The design STILL isn't
finalized, (2) I do not (and won't) tour the country like Clay Spencer,
running treadle hammer-fabrication workshops.  I have no doubt that if I
held a workshop to build Grasshoppers, I'd fill it quickly.  But the
fabrication isn't the fascination to me...
 
Bruce
 


>>> frosty@customcpu.com 11/20/2003 5:58:54 AM >>>

Hmmmm. I don't know if Role Model is exactly how I'd put it. <grin>

It's a matter of perspective, I'm fully aware I don't have a market on
ideas, techniques, nor much of anything so I try to cultivate as many
different perspectives as I can. Playing cards arranged in neat rows
can
look like an inpenetrable brick wall from the wrong perspective.

I too tend to "overthink" projects. However I've, on average, been very
well
served by putting as much work as possible into the front end of a
project.
Usually once I start cutting material I don't hit the 90/90 rule. (The
first
half of a project takes 90% of the time and money and the last half
takes
the other 90% of the time and money)

Probably my biggest weakness (Go ahead &E take a shot <grin>) is math,
it
has to be pretty rudimentary or I'm screwed. I know there have been
several
times I haven't been able to describe something on the list, let alone
defend it because of my lack of math. Things I know from hands on
experience
to be true are none the less indefensible if I can't adequately
describe
them. Oh well.

My compensation on the other hand is visualization; I see mechanisms,
structures, stress, etc. in my minds eye. For example, the first
drawings of
the Grasshopper mechanism you posted were all I needed to build one.
To
design one however I needed to model it, in part on paper and in part
with
sticks. The "weightless" return is very easy for me to "see" as well.

Another example is the scotch yoke I reinvented. Far from being ashamed
I'm
pretty proud of coming up with the idea. What has me slapping my head
though
is how much time I spent reinventing the thing instead of just reading
about
it and adapting it to what I need. <sigh>

Another prime example of not being able to do the math not slowing me
down
much is mitering pipe. I have wrap arounds and sometimes even look at
the
marks for mitering. However I don't use them, I first (straight) cut
the
pipe at the angle I want, then lay it against the other pipe and mark
the
trim cut with dividers. It takes some practice and wastes a little bit
of
pipe (the radius of the pipe being trimmed) but it's fast and
accurate.

Anyway, you and I do things very differently; we have different
training,
professions, philosophies, etc. and hence perspectives. Different
perspectives are important to me, I'd rather attempt a difficult
project
with someone who disagrees than one who agrees with me. There're more
options available, more to learn.

Here's a good example of our different perspectives. To my eye your
design
of the Grasshopper is more complicated than necessary. The reason in
large
part is your "no weld" philosophy. It's my experience more people own
a
welder than a drill press. More importantly, more people can weld than
layout and drill holes accurately .

I wouldn't attempt a Grasshopper linkage without a drill press due to
it's
low tolerance nature. However building the entire hammer to close
tolerance
as a bolt together unit is too daunting for most folk, I certainly
wouldn't
given an alternative

I don't make any claim for superiority of method except for ease of
construction (in this case). I sincerely believe there'd be
grasshopper
hammers all over the place if you offered plans for a welded design.

Frosty
------------------------
If it ain't forged
it ain't real.
Wrought iron is.
The FrostWorks

Meadow Lakes, AK.


----- Original Message -----
From: "Bruce Freeman" <FREEMAB@pt.fdah.com>
To: <theforge@mailman.qth.net>
Sent: Tuesday, November 18, 2003 7:45 AM
Subject: [TheForge] Another Long rambley YAK


> Wow!  Now I'm a role model!  It's scarey!
>

>
> The other thing I do is to study things mathematically.  I think too
> many people shy away from doing calculations because they're "too
hard."
>  Yes, they're hard, but your brain can work through them.  Modern
> software helps a lot too, mainly by allowing you to test multiple
cases,
> one after another.  Even if not programmed in any sophistocated way,
> this sort of calculation is powerful in its ultimate effect.
>

>
> Actually, reinventing the Scotch Yoke is nothing to be ashamed of.
> Mortified by, perhaps, but not ashamed of!
>

>
> When I finally come up with a final design and prototype for the new
TH
> design, I expect there will be more people interested - people like
me
> who will never need or want a power hammer, but who really could use
a
> striker every once in a while.  I'm aiming for many the same features
of
> the GH, but lightweight and cheap to construct WITHOUT welding.
>
> Bruce
> NJ
>

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