twitter: rec.crafts.metalworking - 26 new messages in 11 topics

rec.crafts.metalworking
http://groups.google.com/group/rec.crafts.metalworking?hl=en

rec.crafts.metalworking@googlegroups.com

Today's topics:

==============================================================================
TOPIC: Java -100% buzzword compliant was Education vs Schooling was Glenn Beck
on Who da Commies Is
http://groups.google.com/group/rec.crafts.metalworking/t/90e27bac800d700a?hl=en
==============================================================================

== 1 of 4 ==
Date: Sat, Jan 9 2010 12:26 pm
From: pyotr filipivich

Let the Record show that "Buerste" <buerste@wowway.com> on or about
Fri, 8 Jan 2010 05:39:17 -0500 did write/type or cause to appear in
rec.crafts.metalworking the following:
>"pyotr filipivich" <phamp@mindspring.com> wrote
>> There's a difference between education and schooling. The left is
>> enamored of certificates - of schooling - not of the education. And
>> thanks to fifty years of "free money" for college, we have people
>> schooled far above their ability to comprehend the information. The
>> "hard sciences" weed them out with various courses, but in the soft
>> liberal arts, it is possible to just echo back the teacher's
>> prejudices, become buzzword compliant, and get a degree.

[snip]
>
>Very well said! I love the "buzzword compliant", it says it all.

I love that line. I heard it when attending some of the hoopla
surrounding the rollout of Java. "It is the first language which is
100% buzzword compliant." Much mirth from the assembled nerds.

-
pyotr filipivich
We will drink no whiskey before its nine.
It's eight fifty eight. Close enough!

== 2 of 4 ==
Date: Sat, Jan 9 2010 12:32 pm
From: pyotr filipivich

Let the Record show that "Buerste" <buerste@wowway.com> on or about
Fri, 8 Jan 2010 19:08:12 -0500 did write/type or cause to appear in
rec.crafts.metalworking the following:
>On the other hand, the phenomenal technology available has eliminated a lot
>of the need for the seat-of-the-pants engineering type guys. The software
>available today and the quick prototyping eliminates so much of the human
>expertise. I use Solidworks and my parts and mechanisms don't get built
>until I'm on version four or so. I can test (and break) stuff in the
>software and then the metal version usually works as predicted. We don't
>repair odds and ends things anymore, we buy them off the shelf. The
>availability and price of components is so much cheaper than
>troubleshooting. My mechanics are more parts changers now. There is the
>danger of a person being so far removed from the actual physical process
>that they haven't a clue what hands-on "feel" can mean to the process.

Friend is an engineer. He has a feel for the calculations, what
the numbers ought to be. So when his drafters bring a set of numbers
which don't make sense, he is able to say "Just because they came out
of the computer doesn't make them sacred!"

I keep in mind that the moon shot was largely done with slide
rules and 3 digits of precision. Downside of the "cheap" computers
is that we can run calculations we don't need, to produce graphs which
have no meaning, but look good to the marketing department.

-
pyotr filipivich
We will drink no whiskey before its nine.
It's eight fifty eight. Close enough!

== 3 of 4 ==
Date: Sat, Jan 9 2010 12:59 pm
From: pyotr filipivich

Let the Record show that Andrew VK3BFA <VK3BFA@wia.org.au> on or about
Fri, 8 Jan 2010 19:12:25 -0800 (PST) did write/type or cause to appear
in rec.crafts.metalworking the following:
>
>CAD - yes, can do lots of things, including stress analysis - so you
>can design a part that will do X cycles, then break. (This, combined
>with the Warranty Expiry Chip is pretty commonplace, its a significant
>gripe topic in this group <g>)
>I am learning manual machining, because I need to make unobtainable
>replacement mechanical parts, mainly for electronic gear. (the plastic
>bits break) Would only ever need to make a few, so CNC is not
>warranted for me.

I recall reading of a shop that had not a single CNC machine in
the place. But it had lots of experienced machinists, who could take
a broken part, a sketch on a cocktail napkin, even complete drawings
(!) and make the needed part - RFN! And they charged the big bucks,
but they would have the part complete,long before the CNC guys got
their first draft of the program written. Now, that was back in the
1980s, I've no idea how CNC compares then to now, but ... sometimes,
you don't need fancy drawing.

>I go to trade school with an apprentice group - they are eager to get
>to the CNC sections as thats what they use at work, cant see the need
>for manual machining.

When we started the CNC section, I announced "best to think of the
CNC machine as a very fast, eager and idiot apprentice, who will do
exactly what you said to do. Exactly what you said - not what you
meant." (I'd been a programmer in a previous life.)
>
>So - will we get to the stage where industry is totally dependent on a
>few companies, making thousands of parts on their CNC machines? - (its
>already happened, I think) - I would argue that if you cant operate a
>manual machine, and thus have a "feel" for what the CNC machine is
>trying to do, then you're taking a big risk. Crashing a CNC machine is
>usually big bikkies, and is often done by someone who "forgot" some
>simple parameter.

Yep. And no amount of checking, double checking, and signing off
by leads will protect you from the too solid goof.

I recall a short story, where the"kid" was not doing well on the
standard tests. But The Powers that Be came to him, after he came in
third in the regional finals. He explained that his school had the
Jones model, not the Brown model, and how was he to trouble shoot a
Brown model if he wasn't trained on it? And the suit from the Powers
That Be, pointed out that both Jones and Brown had been individuals
with a talent for working outside the box. Would you like a chance to
join that group?

I remember, right fresh from drafting classes, making a scale
drawing of some furniture I needed to make. Ever try to draw a 3/4
inch (16mm) thick board - six feet (2m) long? To scale? On a
standard letter sized piece of paper? Dad then told me a story of
his youth, as a young Forester, trying to design a replacement bridge
after the spring break up had washed out the old one. He couldn't
figure out how to get one "right". Then the woodrat - the guy who
taught Paul Bunyon - cobbles a crib of logs together, skids it off the
ramp into the creek, Splash - it settles, upright, and you can put a
bridge over the creek. Not square to the road, but "It's done, and it
only has to last until next spring break up."
How precise does it need to be?
-
pyotr filipivich
We will drink no whiskey before its nine.
It's eight fifty eight. Close enough!

== 4 of 4 ==
Date: Sat, Jan 9 2010 12:59 pm
From: pyotr filipivich

And is it always the same 10%?

>You had learnt a lot more, and in
>that pile is the stuff you need. You had no idea at the time what 10%
>you would need. And education? - yes, theres idiots with higher
>degrees, same as theirs idiots with guns and idiots driving cars.
>Thats no reason to ban guns, or cars, or education - its not a
>strictly black and white equation, thats just being stupid.

Sometimes, schooling will teach you what you could learn on the
job. But in much less time.
-
pyotr filipivich
We will drink no whiskey before its nine.
It's eight fifty eight. Close enough!

==============================================================================
TOPIC: Craft? No. Metal? Yes.
http://groups.google.com/group/rec.crafts.metalworking/t/7c60ed228ae39c97?hl=en
==============================================================================

== 1 of 4 ==
Date: Sat, Jan 9 2010 12:42 pm
From: "Bob La Londe"

http://www.yumabassman.com/gallery/details.php?image_id=68

== 2 of 4 ==
Date: Sat, Jan 9 2010 12:59 pm
From: "Bob La Londe"

"Bob La Londe" <none@none.com> wrote in message
news:nT52n.3813$Sk4.564@newsfe10.iad...
> http://www.yumabassman.com/gallery/details.php?image_id=68

== 3 of 4 ==
Date: Sat, Jan 9 2010 1:18 pm
From: Tim Wescott

On Sat, 09 Jan 2010 13:42:58 -0700, Bob La Londe wrote:

> http://www.yumabassman.com/gallery/details.php?image_id=68

Looks like metal to me.

--
www.wescottdesign.com

== 4 of 4 ==
Date: Sat, Jan 9 2010 1:18 pm
From: Tim Wescott

On Sat, 09 Jan 2010 13:59:53 -0700, Bob La Londe wrote:

> "Bob La Londe" <none@none.com> wrote in message
> news:nT52n.3813$Sk4.564@newsfe10.iad...
>> http://www.yumabassman.com/gallery/details.php?image_id=68

Meanie.

--
www.wescottdesign.com

==============================================================================
TOPIC: Time to get tougher
http://groups.google.com/group/rec.crafts.metalworking/t/857dcab3153330a8?hl=en
==============================================================================

== 1 of 2 ==
Date: Sat, Jan 9 2010 12:47 pm
From: Retief

On Sat, 9 Jan 2010 15:19:36 -0500, "Ed Huntress"
<huntres23@optonline.net> wrote:

>So, what's your answer?

Poor Ed, he has gotten so desperate that he now evades the answer,
when it is presented to him.

He apparently believes that if he keeps producing posts in different
subthreads that he can conceal his errors. Pathetic.

Now run along little boy. It's obvious that you neither have the
desire to learn, nor the capability to be taught.
Retief

== 2 of 2 ==
Date: Sat, Jan 9 2010 1:26 pm
From: "Ed Huntress"

"William Wixon" <wwixon@frontiernet.net> wrote in message
news:PN42n.3564$5m.1888@newsfe12.iad...
>
> "Ed Huntress" <huntres23@optonline.net> wrote in message
> news:4b48b83c$0$4995$607ed4bc@cv.net...
>>
>
>
> -snip-
>
>>
>> Don't feel bad. I've seen this question come up online, and in personal
>> discussions, for over 20 years. None of the four-flushers who make
>> statements like yours can ever answer that question. That's because, once
>> the Founders' actual words are shown to them, along with a comment or two
>> from real historians, they realize that someone fed them a line and they
>> believed it, without taking the time to look for themselves.
>>
>> Just so you have it firmly in your mind now, I'll refresh your memory
>> about the words of Madison and Jefferson on the subject:
>>
>> "...A REPUBLIC, by which I mean a government in which the scheme of
>> representation takes place... -- Madison, Federalist 10
>>
>> "It is, that in a DEMOCRACY, the people meet and exercise the government
>> in person; in a REPUBLIC, they assemble and administer it by their
>> representatives and agents." -- Madison, Federalist 14
>>
>> "On this view of the import of the term REPUBLIC, instead of saying, as
>> has been said, -- that it may mean anything or nothing --, we may say
>> with truth and meaning, that governments are more or less REPUBLICAN, as
>> they have more or less of the element of popular election and control in
>> their composition..." -- Jefferson, letter to John Taylor, 1816
>>
>> "Action by the citizens in person, in affairs within their reach and
>> competence, and in all others by representatives, chosen immediately, and
>> removable by themselves, constitutes the essence of a REPUBLIC." --
>> Jefferson, letter to Dupont de Nemours, 1816
>>
>>
>> Keep those handy. They may help you look like less of a butthead at some
>> time in the future.
>>
>> --
>> Ed Huntress
>>
>
> your post made me think i wish we had like 6 public television stations
> instead of only one. my first thought was "why do we only have one public
> television station and why in the world are they constantly struggling to
> survive?!" and then i was like "oh, because people would bitch about
> having to pay taxes to fund it." your post made me wish there'd be a
> public television station running a college level political science course
> (and 5 others running other "citizenship" courses), like, on a loop,
> continuously. if anyone wanted to they could stop by and watch, for as
> long as they could stand it. run the loop constantly even if NOBODY
> watches it just so that information could be out there freely available
> for anyone who might stumble across it and take up an interest in it.
> how come we don't have 6 public television stations in this country!? how
> many other commercial channels are out there? 600?
>
> b.w.

<g> I don't know how many there are. PBS has enough trouble just getting
funding for one -- plus the bigger network stations that get funding for
their own programs.

It would be nice to have more non-commercial stuff like Frontline and Nova,
but even some of the best commercial TV is Ok. I don't have time for it, so
I don't know. Wes watches a lot of C-Span. That's *really* going for
original material. Hats off to him.

Regarding how I come up with things like the Madison quotes and so on, it's
a long story. It has to do with once being humiliated into recognizing what
I needed to do by my college academic advisor, George Will. He had a way of
withering undergraduates into a kind of soft putty, and you wanted to flow
out the door; under it, if necessary. <g>

Anyway, it changed my life.

--
Ed Huntress

==============================================================================
TOPIC: Kinda on-topic: Shoes for Metal Roofs
http://groups.google.com/group/rec.crafts.metalworking/t/fc18d5322feea788?hl=en
==============================================================================

== 1 of 5 ==
Date: Sat, Jan 9 2010 12:48 pm
From: Tim Wescott

On Sat, 09 Jan 2010 15:08:41 -0500, Brian Lawson wrote:

> On Sat, 09 Jan 2010 13:17:02 -0600, Tim Wescott <tim@seemywebsite.com>
> wrote:
>
>>So, every roof on the property is now metal. Our house roof is the
>>raised metal-tab stuff, and when it gets the least bit wet it's slicker
>>than snot -- to the point where we've already had a family member fall
>>off and injure himself (not badly, but still a good warning).
>>
>>My New Balance tenny runners don't grip it when it's wet, I can just
>>barely keep traction by sitting down on it in jeans -- and denim usually
>>grips metal roofs pretty well.
>>
>>So, are there any trick shoes, or shoe attachements, that one can wear
>>to keep from falling and breaking one's neck? Any of them that don't
>>cost an arm and a leg, yet still really work?
>>
>>TIA
>
>
> Hey Tim,
>
> Not real sure why you want to wander around on the roof, but "deck
> shoes" for yachting have a pretty neat tread. They work pretty well on
> wet fibreglas/gel-coat. Try West Marine store or similar.
>
Basic maintenance, keeping the fir needles (fir needle tea is mildly
acidic, and corrosive), fixing the old leaky ones, etc.

Why else?

--
www.wescottdesign.com

== 2 of 5 ==
Date: Sat, Jan 9 2010 12:49 pm
From: Tim Wescott

On Sat, 09 Jan 2010 14:13:46 -0600, Pete C. wrote:

> Tim Wescott wrote:
>>
>> So, every roof on the property is now metal. Our house roof is the
>> raised metal-tab stuff, and when it gets the least bit wet it's slicker
>> than snot -- to the point where we've already had a family member fall
>> off and injure himself (not badly, but still a good warning).
>>
>> My New Balance tenny runners don't grip it when it's wet, I can just
>> barely keep traction by sitting down on it in jeans -- and denim
>> usually grips metal roofs pretty well.
>>
>> So, are there any trick shoes, or shoe attachements, that one can wear
>> to keep from falling and breaking one's neck? Any of them that don't
>> cost an arm and a leg, yet still really work?
>>
>> TIA
>>
>> --
>> www.wescottdesign.com
>
> Something like rock climbing shoes might help, but really the proper
> thing is a fall protection package with appropriate harness, rope grab,
> rope and anchor brackets. They aren't particularly expensive and you
> should be able to buy a suitable kit at a ladder and scaffolding
> supplier.

I've considered that, even if it isn't manly (the roofers that put on our
roof just brag about broken bones). How do you anchor them when the roof
you're on is the highest thing around?

--
www.wescottdesign.com

== 3 of 5 ==
Date: Sat, Jan 9 2010 1:16 pm
From: "Pete C."

Tim Wescott wrote:
>
> On Sat, 09 Jan 2010 14:13:46 -0600, Pete C. wrote:
>
> > Tim Wescott wrote:
> >>
> >> So, every roof on the property is now metal. Our house roof is the
> >> raised metal-tab stuff, and when it gets the least bit wet it's slicker
> >> than snot -- to the point where we've already had a family member fall
> >> off and injure himself (not badly, but still a good warning).
> >>
> >> My New Balance tenny runners don't grip it when it's wet, I can just
> >> barely keep traction by sitting down on it in jeans -- and denim
> >> usually grips metal roofs pretty well.
> >>
> >> So, are there any trick shoes, or shoe attachements, that one can wear
> >> to keep from falling and breaking one's neck? Any of them that don't
> >> cost an arm and a leg, yet still really work?
> >>
> >> TIA
> >>
> >> --
> >> www.wescottdesign.com
> >
> > Something like rock climbing shoes might help, but really the proper
> > thing is a fall protection package with appropriate harness, rope grab,
> > rope and anchor brackets. They aren't particularly expensive and you
> > should be able to buy a suitable kit at a ladder and scaffolding
> > supplier.
>
> I've considered that, even if it isn't manly (the roofers that put on our
> roof just brag about broken bones). How do you anchor them when the roof
> you're on is the highest thing around?
>
> --
> www.wescottdesign.com

There are ridge anchors available, both temporary ones intended to be
screwed in place, as well nice stainless ones intended for permanent
installation.

Of course the first up and last down can be unprotected, but you are
also not carrying tools at that point and can be extra cautious.

== 4 of 5 ==
Date: Sat, Jan 9 2010 1:25 pm
From: "Pete C."

Tim Wescott wrote:
>
> On Sat, 09 Jan 2010 15:08:41 -0500, Brian Lawson wrote:
>
> > On Sat, 09 Jan 2010 13:17:02 -0600, Tim Wescott <tim@seemywebsite.com>
> > wrote:
> >
> >>So, every roof on the property is now metal. Our house roof is the
> >>raised metal-tab stuff, and when it gets the least bit wet it's slicker
> >>than snot -- to the point where we've already had a family member fall
> >>off and injure himself (not badly, but still a good warning).
> >>
> >>My New Balance tenny runners don't grip it when it's wet, I can just
> >>barely keep traction by sitting down on it in jeans -- and denim usually
> >>grips metal roofs pretty well.
> >>
> >>So, are there any trick shoes, or shoe attachements, that one can wear
> >>to keep from falling and breaking one's neck? Any of them that don't
> >>cost an arm and a leg, yet still really work?
> >>
> >>TIA
> >
> >
> > Hey Tim,
> >
> > Not real sure why you want to wander around on the roof, but "deck
> > shoes" for yachting have a pretty neat tread. They work pretty well on
> > wet fibreglas/gel-coat. Try West Marine store or similar.
> >
> Basic maintenance, keeping the fir needles (fir needle tea is mildly
> acidic, and corrosive), fixing the old leaky ones, etc.
>
> Why else?
>
> --
> www.wescottdesign.com

A pressure washer with an extension pole and 180 angle head ought to
take care of cleaning from ground level.

== 5 of 5 ==
Date: Sat, Jan 9 2010 2:14 pm
From: "Ed Huntress"

"Pete C." <aux3.DOH.4@snet.net> wrote in message
news:4b48f126$0$17777$ec3e2dad@unlimited.usenetmonster.com...
>
> Tim Wescott wrote:
>>
>> On Sat, 09 Jan 2010 14:13:46 -0600, Pete C. wrote:
>>
>> > Tim Wescott wrote:
>> >>
>> >> So, every roof on the property is now metal. Our house roof is the
>> >> raised metal-tab stuff, and when it gets the least bit wet it's
>> >> slicker
>> >> than snot -- to the point where we've already had a family member fall
>> >> off and injure himself (not badly, but still a good warning).
>> >>
>> >> My New Balance tenny runners don't grip it when it's wet, I can just
>> >> barely keep traction by sitting down on it in jeans -- and denim
>> >> usually grips metal roofs pretty well.
>> >>
>> >> So, are there any trick shoes, or shoe attachements, that one can wear
>> >> to keep from falling and breaking one's neck? Any of them that don't
>> >> cost an arm and a leg, yet still really work?
>> >>
>> >> TIA
>> >>
>> >> --
>> >> www.wescottdesign.com
>> >
>> > Something like rock climbing shoes might help, but really the proper
>> > thing is a fall protection package with appropriate harness, rope grab,
>> > rope and anchor brackets. They aren't particularly expensive and you
>> > should be able to buy a suitable kit at a ladder and scaffolding
>> > supplier.
>>
>> I've considered that, even if it isn't manly (the roofers that put on our
>> roof just brag about broken bones). How do you anchor them when the roof
>> you're on is the highest thing around?
>>
>> --
>> www.wescottdesign.com
>
> There are ridge anchors available, both temporary ones intended to be
> screwed in place, as well nice stainless ones intended for permanent
> installation.
>
> Of course the first up and last down can be unprotected, but you are
> also not carrying tools at that point and can be extra cautious.

I intend to get some of the safety gear described in this thread, but I keep
putting it off. Meantime, I throw a long length (around 75 feet) of 5/8"
nylon line over the ridge of the house, tying the standing end off to a tree
in one case, or to a masonry porch column if I'm working on the back.

Then I tie a bowline-on-a-bight into the line at an appropriate distance. If
I have to move much, I re-tie the knot.

It's inconvenient and it's not 100%, but a fall from my two-story roof, at
my age, would change my life in a bad way if it didn't kill me. I'm willing
to take the extra time.

--
Ed Huntress

==============================================================================
TOPIC: Serious press fit
http://groups.google.com/group/rec.crafts.metalworking/t/d1a444f85cb0de51?hl=en
==============================================================================

== 1 of 1 ==
Date: Sat, Jan 9 2010 1:18 pm
From: Joseph Gwinn

In article <4b48cfd8$0$22515$607ed4bc@cv.net>,
"Ed Huntress" <huntres23@optonline.net> wrote:

> "Joseph Gwinn" <joegwinn@comcast.net> wrote in message
> news:joegwinn-00490A.11422809012010@news.giganews.com...
> > In article <4b47f8ef$0$31278$607ed4bc@cv.net>,
> > "Ed Huntress" <huntres23@optonline.net> wrote:
> >
> >> "JR North" <junkjasonrnorth@bigfoot.com> wrote in message
> >> news:8vsfk5dlafq8o8uc0qmvi59gkv96petpp9@4ax.com...
> >> > The stupidity of this design is mind-boggling. Import engines,
> >> > especially Toyota, all have slip-on dampeners, with a couple 10's
> >> > clearance. There is absolutely no need to have a press fit, except to
> >> > demonstrate their inability to machine the crank and dampener to such
> >> > close tolerance.
> >> > JR
> >> > Dweller in the cellar
> >>
> >> How do Toyota and others fix those dampeners to their shafts?
> >>
> >> One advantage of a press fit, especially for such heavily loaded joints
> >> as
> >> those between a flywheel and the shaft of a piston engine, is that there
> >> is
> >> no keyway to weaken the shaft and to produce a stress raiser in both
> >> mating
> >> parts. It's frustrating for those of us who like to repair things, but
> >> the
> >> big issue today, as we've all noticed, is not ease of repair. I wanted to
> >> strangle the nearest Korean last week when I had to replace a headlamp in
> >> my
> >> Hyundai, in a place that looked like it was intentionally designed to
> >> tear
> >> up your knuckles and to give you cramps in your fingers. <g>
> >
> > Your hands are too big, I bet.
>
> They're not very big, but they're a lot bigger than those of the average
> Asian woman, I suspect.
>
> They don't have nearly enough joints to do the job, either. I think you need
> about five in each finger, and they have to bend in all axes.

I've heard that they are very flexible.

Joe Gwinn

> BTW, I can change a bulb in the left headlamp in roughly 2 minutes. In the
> right headlamp, it's a half-hour plus. And I need bent-tip needle-nose
> pliers to release the spring clamp. I've had to replace the right bulb
> twice, and my blood pressure probably jumped 20 points each time.
>
> >
> > War story: In the early 1970s, a penurious friend asked me to repair
> > the lightmeter on her old Nikon (F1?). The repair was easy - just
> > solder the wire back onto the meter, and lace the wire down with waxed
> > dental floss so it wouldn't flop and break.
> >
> > Then I tried to put the camera back together. No dice - fingers too
> > large. This brought to mind those advertising shots of the assembly
> > area, with ranks of benches each with a five-foot-nothing woman at work.
> > Their thumbs might be the size of my pinky. Laughed, took camera back
> > apart, lengthened the wires, and then was able to reassemble the camera.
> >
> > Joe Gwinn
>
> There's usually a solution. Sometimes it requires re-design. <g>

==============================================================================
TOPIC: Odd Q on machine stability
http://groups.google.com/group/rec.crafts.metalworking/t/68a493440a840bfb?hl=en
==============================================================================

== 1 of 3 ==
Date: Sat, Jan 9 2010 1:56 pm
From: Jim Wilkins

On Jan 9, 2:27 pm, "Existential Angst" <UNfit...@UNoptonline.net>
wrote:
> ...
> Suppose a machine -- cnc or manual -- was placed on a very light but very
> rigid base, which was then suspended in the air by 4 or so guy wires from
> overhead beams....
> How would that affect its performance, accuracy, etc.?
> Iny thoughts?
> EA

Air-supported tables like these are the standard in optics labs, and
we put our wafer probes and microscopes on them at Unitrode:
http://www.newport.com/Optical-Tables-and-Vibration-Control/137658/1033/catalog.aspx

The large leg in each corner contains a rolling diaphram air cylinder
controlled by a position regulator that does a pretty good job of
keeping the table level, much better than springs would. They work
very well until you need to torque larger fasteners, then they bob and
rock like a diving float.

jsw

== 2 of 3 ==
Date: Sat, Jan 9 2010 3:02 pm
From: Kirk Gordon

Existential Angst wrote:
> Awl --
>
> Several times mention has been made of dancing machines, and the importance
> of firm anchoring, level-ness, etc.
>
> Suppose a machine -- cnc or manual -- was placed on a very light but very
> rigid base, which was then suspended in the air by 4 or so guy wires from
> overhead beams.
> So the machine would be level and un-twisted because of this light rigid
> base, but it would be free to swing.
>
> How would that affect its performance, accuracy, etc.?
>
> I would hazard to say that there would be no ill effects at all, cuz of
> well, Newton'n'shit.....
> Heh, if there were springs in the guy wires, sure would help with building
> vibration, wouldnit?
>
> But, I was wrong once before, and it could happen again.....
>
> Iny thoughts?
>

Dood!

Einstein was good at "thought experiments". You're not. And Newton
is gonna kick yer ass in five or six different dimensions if you ever
try this for real.

First, there's that stuff about how a body at rest tends to remain
at rest unless acted upon by drugs or alchohol or something. That does
NOT refer to the whole body, if said body is made of parts that can move
with respect to each other. What it refers to is the center of the
body's inertial mass. So when you hit the rapid button and make the
machine's table move to the left, everything else about the machine is
going to move a bit to the right, so the center of mass stays where it
was. And if you move the saddle away from you, the rest of the machine
will come toward you. Etc. And that's gonna be a problem.

If the guy wires were all taught and balanced and everything before
you moved the table, they're not going to be that way after you move it.
The platform and machine body are now in a different place, having
moved to compensate for the change in mass distribution when you jogged
X. So the tension on the wires is now unequal. And, gravity being what
it is, the whole machine and base will start another bit of movement,
swinging pendulum style toward a new location where the tension in the
wires is equalized again. And that swing won't go away till friction
eats it, which can take a very long time. And every new axis motion
will add to the swing. And add to it. And ADD to it. And so on.

If you attempt to move Z the wires will either loosen a bit (Z-
motion) or tighten a bit (Z+), for the same Newtonian reasons. And,
since wires (or anything else, if you stress it enough) are elastic,
they'll just naturally want to "rebound" a bit when the motion stops.
So in addition to swinging back and forth from XY motions, your poor
dizzy Fadal will now be bouncing up and down, platform and all. And
don't even THINK about adding springs!

Worse, none of the moving parts of your Fadal is likely to have its
own center of mass on a line that goes through the center of mass of the
whole machine. That means the forces described above will form
"couples", which will cause rotation. When the table moves left or
right, the machine won't just pendulum swing in the other direction.
It'll also try to twist itself around it's center of mass. Viewed from
the operator's position, it'll twist clockwise if you move left, and ccw
if you move right, or vise versa, depending on whether the X mass is
located above or below the main mass center. Same problem when you move
Y or Z (top of machine twists toward you or away from you). This causes
even more distress for the poor guy wires, which will now be out of
balance in god knows how many ways, and will need to hang on while the
whole machine does some MORE pendulum/gravity swinging to equalize
everything all over again.

And before you know it, you and your poor machine will be swinging
back and forth like a 10,000 pound tether ball, twisting in at least
three axes simultaneously, and screaming like a kid on one of those
insane multi-dimensional amusement park rides that's specifically
engineered to make people lose their lunches from both ends at once.

And then, since you asked, there's the small problem of vibration.
And here's the relevant question: If you were a machine tool, and if
you had a whole bunch of nasty little compression waves running all over
the inside of your body, and if you really REALLY wanted those waves to
go away, becaue they hurt, and itch, and make your eyes water, and more,
what would you most like to grab hold of for stability?

A. Some long, skinny, flexible, stretchy pieces of cable?

B. A big-ass chunk of concrete, conveniently attached to the entire
earth, with all its zillion trillion gazzillion tons of rock and iron
and stuff?

If you guessed A, you'd better own a good helmet and a generous
supply of barf bags.

Nuff said. Have fun!

== 3 of 3 ==
Date: Sat, Jan 9 2010 3:03 pm
From: "DoN. Nichols"

On 2010-01-09, Jim Wilkins <kb1dal@gmail.com> wrote:
> On Jan 9, 2:27�pm, "Existential Angst" <UNfit...@UNoptonline.net>
> wrote:
>> ...
>> Suppose a machine -- cnc or manual -- was placed on a very light but very
>> rigid base, which was then suspended in the air by 4 or so guy wires from
>> overhead beams....
>> How would that affect its performance, accuracy, etc.?
>> Iny thoughts?
>> EA
>
> Air-supported tables like these are the standard in optics labs, and
> we put our wafer probes and microscopes on them at Unitrode:
> http://www.newport.com/Optical-Tables-and-Vibration-Control/137658/1033/catalog.aspx

I remember those well. We had them in our laser labs.

> The large leg in each corner contains a rolling diaphram air cylinder
> controlled by a position regulator that does a pretty good job of
> keeping the table level, much better than springs would. They work
> very well until you need to torque larger fasteners, then they bob and
> rock like a diving float.

Also -- watching as you put something heavy on one corner, and
after it stabilizes, take it off and watch again.

Enjoy,
DoN.

--
Email: <dnichols@d-and-d.com> | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

==============================================================================
TOPIC: USDA Climate Zone Changes 1990 to 2006
http://groups.google.com/group/rec.crafts.metalworking/t/2c644d95a02f628e?hl=en
==============================================================================

== 1 of 1 ==
Date: Sat, Jan 9 2010 1:58 pm
From: columbiaaccidentinvestigation

On Jan 9, 12:07 pm, "IC" <I...@good.guy> wrote:
> On Sat, 9 Jan 2010 10:50:27 -0800 (PST), columbiaaccidentinvestigation
>
> <columbiaaccidentinvestigat...@yahoo.com> wrote:
> >[snip]
>
> >oh man, the typical mantra of the right, but people like you won't
> >admit that the private sector cannot provide an adequate safety net
> >for the less fortunate in our society, and instead you need to hide
> >behind bs posts like above.
>
> I read this by accident, and learned something,
> I didn't know this flake was a leftist, like all the goofy
> hard core democrats and socialists who think "the
> government has lots of money, and can pay for all
> the needs of the needy".
>
> It is ok by me if they do, but with the present
> system almost everyplace in the world they can't
> do it without sucking the life blood of economic
> activity out of the financial and private sectors.
>
> The general public is waking up and many
> demonstrations are going on, the people that
> have brains see that taxation and borrowing
> is like flying a plane into a hillside, something
> needs to be done, only nobody seems to know
> what to do, maybe somebody will read the last
> message I just posted.
>
> cai can kiss-off.

Thats a pathetic presentation of somebody elses views, funny how a
reactionary like you needs to use lame assertions to prop up your
argument, now run along.

http://feedingamerica.org/foodbank-results.aspx
Food Bank ResultsFood Bank Locator
Locate the Feeding America food bank that serves your local community.

NOVEMBER 18, 2009 More Households Request Food Aid
http://online.wsj.com/article/SB125839283643150795.html

http://www2.counton2.com/cbd/news/local/article/organization_offers_help_to_those_in_need/92439/
Homeless shelter has $45K budget shortfall after double the number of
people are in need

==============================================================================
TOPIC: Wes, 6913 lathe
http://groups.google.com/group/rec.crafts.metalworking/t/ee6f9f685251a34d?hl=en
==============================================================================

== 1 of 1 ==
Date: Sat, Jan 9 2010 1:58 pm
From: Wes

On Fri, 08 Jan 2010 17:00:55 -0600, Ignoramus8952
<ignoramus8952@NOSPAM.8952.invalid> wrote:

>> Iggy, sorry, forgot the mirror tonight. I also owe you a measurement on the 4 1/2T to 5C
>> adaptor. I'll do it tomorrow.
>>
>
>Wes, no problem, I did not want to make trouble, just to find out if
>you already know.
>
>i

I checked the motor data plate. 1800 rpm.

On that adaptor, I measured mine, the one I pointed you to matches his
numbers within the limitations of measuring with calipers.

Wes

==============================================================================
TOPIC: 0.3 IPM
http://groups.google.com/group/rec.crafts.metalworking/t/f7ca0615bd481b5e?hl=en
==============================================================================

== 1 of 3 ==
Date: Sat, Jan 9 2010 1:59 pm
From: "Bob La Londe"

At 0.3 IPM feed rate I am in the process of rough cutting a block down by
about 1.5 inches.

http://www.yumabassman.com/gallery/details.php?image_id=69

I have been fascinated with a table surface level vise for my mini mill to
maximize cutting depth on some projects. I have been in the process of
cutting down the jaws of a broken cross slide vise to provide the jaws on my
table vise. The first jaw I machined off one pass at a time with an end
mill. I was able to take off about .007 per pass with a 1/4" tin coated end
mill. That took about 2 days. A stupid amount of time. I came up with
this idea to rough cut the thing to within .1. Its on the third cut now and
Its been less than 30 minutes.

My thought is I can cut all four sides, Split it with a hammer and chisel,
and then finish cut it with my end mill. The area where my t-bolts will go
is in the area being cut by the abrasive wheel. so I will not need to worry
about pockets from the broken area causing uneven clamping to the table. I
figured it it works, I will just cut a slight pocket with beveled edge in
that area to be safe.

Getting in a hurry cost me my first two abrasive wheel and a mandrel, but
they abrasive wheel is holding up amazingly well. This one has cut about .5
deep for 5 - 6 inches so far and looks to be less than 1/16 worn away.
Obviously a solid straight line of cut improves the life of these wheels
dramatically. I was planning on having to go to the store to buy more
wheel. Instead if I had been a little less aggressive with my first couple
I would have new wheels still to spare.

Yes Pete. I wrote a line of code to do each cut. Geez.

== 2 of 3 ==
Date: Sat, Jan 9 2010 2:25 pm
From: Jim Wilkins

On Jan 9, 4:59 pm, "Bob La Londe" <n...@none.com> wrote:
> At 0.3 IPM feed rate I am in the process of rough cutting a block down by
> about 1.5 inches.
> http://www.yumabassman.com/gallery/details.php?image_id=69
> I have been fascinated with a table surface level vise for my mini mill to
> maximize cutting depth on some projects. ...

http://www.miteebite.com/
http://www.use-enco.com/CGI/INSRIT?PARTPG=INLMKD&PMPXNO=949638&PMAKA=425-7403

jsw

== 3 of 3 ==
Date: Sat, Jan 9 2010 2:58 pm
From: "Bob La Londe"

"Jim Wilkins" <kb1dal@gmail.com> wrote in message
news:799f306a-9245-452a-b263-a77183095e9c@a21g2000yqc.googlegroups.com...
> On Jan 9, 4:59 pm, "Bob La Londe" <n...@none.com> wrote:
>> At 0.3 IPM feed rate I am in the process of rough cutting a block down by
>> about 1.5 inches.
>> http://www.yumabassman.com/gallery/details.php?image_id=69
>> I have been fascinated with a table surface level vise for my mini mill
>> to
>> maximize cutting depth on some projects. ...
>
> http://www.miteebite.com/
> http://www.use-enco.com/CGI/INSRIT?PARTPG=INLMKD&PMPXNO=949638&PMAKA=425-7403
>
> jsw

No! Dag Nab-it!!! I looked for something just right for months. Now that
I figured out how to make one and wasted thousands worth of dollars of time
I'm going to make one! LOL.

==============================================================================
TOPIC: OT: Idiots in the media...
http://groups.google.com/group/rec.crafts.metalworking/t/c4735f3d5e3a7aa7?hl=en
==============================================================================

== 1 of 1 ==
Date: Sat, Jan 9 2010 2:04 pm
From: Jim Wilkins

On Jan 9, 3:26 pm, pyotr filipivich <ph...@mindspring.com> wrote:
> Jim Wilkins <kb1...@gmail.com> napisal:

> >Once the youtube video has downloaded look for the large .flv file in /
> >Documents and Settings/ and copy it elsewhere. The VLC player can open
> >it.
>
> There is a downloadhelper add-on for firefox which will download
> the flv file and convert to wmv, or D/L the mp4 file.
>
> Weee!

This is supposed to save youtube videos, but it doesn't always work
for me:
http://keepvid.com/

jsw

==============================================================================
TOPIC: A little metal project
http://groups.google.com/group/rec.crafts.metalworking/t/3700e4ee54df5fc3?hl=en
==============================================================================

== 1 of 1 ==
Date: Sat, Jan 9 2010 3:01 pm
From: Jim Wilkins

On Jan 9, 3:03 pm, Brian Lawson <laws...@ciaccess.com> wrote:
> On Sat, 09 Jan 2010 10:04:25 -0500, Spehro Pefhany
> >On Fri, 08 Jan 2010 23:45:09 -0600, the renowned Don Foreman
>
> >>... > >>hysteretic switching current regulator ...220 uH inductor
> >>...MCP6022 opamp, MOSFET, Schottky diode, sense
> >>resistor and voltage reference.
>
> >...> >a flyback converter using a UC3843 (clone), with the usual TL431 2.5V
> >reference/optoisolator feedback, so changing the resistor ratio on the
> >TL431 would allow the voltage to be lowered to something like 3.5V. ...
> >Spehro Pefhany
>
> Hey you two,
>
> I know there's lots of OT stuff here on RCM, but it's ALMOST ALWAYS in
> ENGLISH !!!
> So how about sticking with the common language in this thread!?!?!?
>
> Heh heh heh.
>
> Brian Lawson,
> Bothwell, Ontario.

I mentioned earlier working for both MEs and EEs. They don't
understand each others' secret language and aren't always too happy
that I do.

jsw

==============================================================================

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Saturday, January 9, 2010

rec.crafts.metalworking - 26 new messages in 11 topics - digest

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