On Sat, 23 Nov 2013 23:47:12 -0600, Leon lcb11211@swbelldotnet
The back of the cabinets have face frames also. The back face frames
however are assembled with lap joints that join with the rabbets on the
inside edges. The center back stiles are part of the back face frame
and it too has rabbets. The rabbets are 1/2" deep and 1/2" wide. The
back panels fit in to the rabbets from the back side.

No need to send me a Sketchup file, I understand perfectly. But, your
explanation leads me to a few more questions. Are the back face frames
for support, visualization, a combination of both or maybe something
else?

And, how are you fastening the back panels? If the back face frames
are 3/4" initially, removing a rabbet of 1/2" leaves only 1/4". I'm
guessing some type of glazier points or something similar?

Thanks.

On 11/24/2013 12:00 AM, Gunner Asch wrote:
On Sat, 23 Nov 2013 23:33:15 -0500, "Mike Marlow"
wrote:

Gunner Asch wrote:


Ayup...aerospace requires 50 millions or half 10ths all the time.

Which is damned hard to do with machines that hold +/- 2 tenths


One might think it is impossible to do with repeatability and assurance.

Hardly impossible. It happens many thousands..hundreds of thousands
of parts a day.

So - I am curious - what is it that aerospace requires that is 50
"millions"? I worked in that space for a while and I never saw any
tolerances like that - but that does not say much. I believe that even the
space shuttle does not demand tolerances that close - but I really do not
know.

Jet engine parts, microwave wave guides, thousands of things. Most of
which I was not cleared to know what they were when I ran into them..
An awful lot of optical stuff is that or more.

Shrug. And a lot of that stuff I figured would be good at
+0/- .001...but..the specs...

As the truism goes...the more zeros you add to the right of the
decimal point...you multiply the cost by a factor of 5-10


Half a thou? (NOBODY says 50 millionths!)
Integrated circuit transistor sizes run less than 200 nanometers. (for
CAD tolerance, not wood working, ok? Sheesh!)


Mike, as to getting to orbit, the precision required is nowhere near
that tight. It's actually fairly sloppy for a successful orbit. SPEED
it the key player there, not trajectory. 20,000 MPH straight down the
east bound lane of I-30 will do just fine. It won't be a circular
orbit, but you won't be back any time soon.

On Sat, 23 Nov 2013 23:01:06 -0600, Gordon Shumway
wrote:

On Sat, 23 Nov 2013 23:33:15 -0500, "Mike Marlow"
wrote:

Gunner Asch wrote:


Ayup...aerospace requires 50 millions or half 10ths all the time.

Which is damned hard to do with machines that hold +/- 2 tenths


One might think it is impossible to do with repeatability and assurance.

So - I am curious - what is it that aerospace requires that is 50
"millions"? I worked in that space for a while and I never saw any
tolerances like that - but that does not say much. I believe that even the
space shuttle does not demand tolerances that close - but I really do not
know.

Knowing nothing about aerospace I am willing to hazard a guess. I
presume the space shuttle does not require tolerances anywhere near
MILLIONTHS of an inch but I presume the shuttle's trajectory
calculations would. I imagine that a rounding error would be the
difference between a successful orbit or crashing into Homer Simpson's
house in Springfield.

A lot of it has to do with rates of expansion and contraction between
different metals. If a part that has a hard alloy piston contracts
more than the piston does when its -250F (outer space)....its nice to
know that the critter isnt going to bind up after its in orbit...so
fits are carefully calculated.

Notice the old SR-71 leaked fuel like a freaking sieve when it was on
the ground..but after the fuselage heated up in flight..all the cracks
closed up nicely and the fuel leaks stopped. Hence the SR-71 needed to
be refueled after takeoff run..then it would go like a sombitch around
the planet before needing another refueling.

Gunner


__
"A human being should be able to change a diaper, plan an invasion,
butcher a hog, conn a ship, design a building, write a sonnet,
balance accounts, build a wall, set a bone, comfort the dying,
take orders, give orders, cooperate, act alone, solve equations,
analyze a new problem, pitch manure, program a computer,
cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects."
- Heinlein

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On Sun, 24 Nov 2013 00:20:47 -0600, Richard
wrote:

On 11/24/2013 12:00 AM, Gunner Asch wrote:
On Sat, 23 Nov 2013 23:33:15 -0500, "Mike Marlow"
wrote:

Gunner Asch wrote:


Ayup...aerospace requires 50 millions or half 10ths all the time.

Which is damned hard to do with machines that hold +/- 2 tenths


One might think it is impossible to do with repeatability and assurance.

Hardly impossible. It happens many thousands..hundreds of thousands
of parts a day.

So - I am curious - what is it that aerospace requires that is 50
"millions"? I worked in that space for a while and I never saw any
tolerances like that - but that does not say much. I believe that even the
space shuttle does not demand tolerances that close - but I really do not
know.

Jet engine parts, microwave wave guides, thousands of things. Most of
which I was not cleared to know what they were when I ran into them..
An awful lot of optical stuff is that or more.

Shrug. And a lot of that stuff I figured would be good at
+0/- .001...but..the specs...

As the truism goes...the more zeros you add to the right of the
decimal point...you multiply the cost by a factor of 5-10


Half a thou? (NOBODY says 50 millionths!)

Half a thou isnt 50 millionths. Its only 5 tenths.
Half a tenth..is 50 millionths.


Integrated circuit transistor sizes run less than 200 nanometers. (for
CAD tolerance, not wood working, ok? Sheesh!)


Mike, as to getting to orbit, the precision required is nowhere near
that tight. It's actually fairly sloppy for a successful orbit. SPEED
it the key player there, not trajectory. 20,000 MPH straight down the
east bound lane of I-30 will do just fine. It won't be a circular
orbit, but you won't be back any time soon.

__
"A human being should be able to change a diaper, plan an invasion,
butcher a hog, conn a ship, design a building, write a sonnet,
balance accounts, build a wall, set a bone, comfort the dying,
take orders, give orders, cooperate, act alone, solve equations,
analyze a new problem, pitch manure, program a computer,
cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects."
- Heinlein

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On Saturday, 23 November 2013 21:17:28 UTC, Leon wrote:

While we are bragging,

http://www.flickr.com/photos/lcb1121...7630857421932/

And with the exception of a couple of older pieces I have built all of
these in the last three years and after I converted to Sketchup.
AFWIW all joint details were drawn in Sketchup.


Hi Leon,

What is this:

http://www.flickr.com/photos/lcb1121...7630857421932/

??

I assume it's something to do with sewing due to the cotton reel, but
my tiny mind can't imagine what the whole thing would be for (which isn't
a shock, really!)

Cheers.

On Sun, 24 Nov 2013 04:55:04 -0800 (PST), wrote:
http://www.flickr.com/photos/lcb1121...7630857421932/
I assume it's something to do with sewing due to the cotton reel, but
my tiny mind can't imagine what the whole thing would be for (which isn't
a shock, really!)

I believe it's a quilting machine.

On Sunday, 24 November 2013 12:59:04 UTC, wrote:

I believe it's a quilting machine.

Yeah, you know, after sending that question, and with dismal predictability, I saw the other posting about it!

Cheers!

"Mike Marlow" wrote in message
...
Gunner Asch wrote:
Ayup...aerospace requires 50 millions or half 10ths all the time.
Which is damned hard to do with machines that hold +/- 2 tenths

One might think it is impossible to do with repeatability and
assurance.

So - I am curious - what is it that aerospace requires that is 50
"millions"? I worked in that space for a while and I never saw any
tolerances like that - but that does not say much. I believe that
even the space shuttle does not demand tolerances that close - but I
really do not know.
-Mike-


What is the tolerance for hydraulic spool valves?

Jim Wilkins wrote:
"Mike Marlow" wrote in message
...
Gunner Asch wrote:
Ayup...aerospace requires 50 millions or half 10ths all the time.
Which is damned hard to do with machines that hold +/- 2 tenths

One might think it is impossible to do with repeatability and
assurance.

So - I am curious - what is it that aerospace requires that is 50
"millions"? I worked in that space for a while and I never saw any
tolerances like that - but that does not say much. I believe that
even the space shuttle does not demand tolerances that close - but I
really do not know.
-Mike-


What is the tolerance for hydraulic spool valves?

You forced me to look that one up. A quick look seems to indicate that
tolerances are around 5 ten thousanths of an inch.

--

-Mike-

"Mike Marlow" wrote in message
...
Jim Wilkins wrote:

What is the tolerance for hydraulic spool valves?

You forced me to look that one up. A quick look seems to indicate
that tolerances are around 5 ten thousanths of an inch.
-Mike-

I did too. The last post claims .000025" to .000040" clearance for
aircraft valves.
http://www.practicalmachinist.com/vb...arance-232520/

jsw

"Jim Wilkins" fired this volley in news:l6suie$fts
:

What is the tolerance for hydraulic spool valves?

A few tenths, usually. And then, only that close when they pay really
close attention to the coefficients of expansion of the spool and the
frame.

Remember that there has to be enough room between parts to develop a film
of lubricating (and sealing) oil, or they don't work.

There's an old (perhaps true) mythos about when Royce/Rolls first
introduced an automatic transmission. They were adamant about making it
to much tighter tolerances than "consumer" trannies, because they
demanded the utmost in 'quality'. Then they discovered that the valve
body and shuttles HAD to be sloppy in order to work at all. G

Lloyd

On 11/24/2013 8:15 AM, Lloyd E. Sponenburgh wrote:

There's an old (perhaps true) mythos about when Royce/Rolls first
introduced an automatic transmission. They were adamant about making it
to much tighter tolerances than "consumer" trannies, because they
demanded the utmost in 'quality'. Then they discovered that the valve
body and shuttles HAD to be sloppy in order to work at all. G

John Browning's 1911 .45ACP:

With too tight tolerances, the pistol is unreliable in combat conditions
due to mud, dirt, dust and the debris of a combat environment, and the
guaranteed likelihood of not being able to keep it clean and lubricated
on a regular basis.

That built in sloppiness sacrificed accuracy for reliability, but made
for an excellent tradeoff for a weapon used mostly in close quarters.

--
eWoodShop: www.eWoodShop.com
Wood Shop: www.e-WoodShop.net
google.com/+KarlCaillouet
http://www.custommade.com/by/ewoodshop/
KarlCaillouet@ (the obvious)

On 11/24/2013 12:45 AM, Gunner Asch wrote:
On Sun, 24 Nov 2013 00:20:47 -0600, Richard
wrote:

On 11/24/2013 12:00 AM, Gunner Asch wrote:
On Sat, 23 Nov 2013 23:33:15 -0500, "Mike Marlow"
wrote:

Gunner Asch wrote:


Ayup...aerospace requires 50 millions or half 10ths all the time.

Which is damned hard to do with machines that hold +/- 2 tenths


One might think it is impossible to do with repeatability and assurance.

Hardly impossible. It happens many thousands..hundreds of thousands
of parts a day.

So - I am curious - what is it that aerospace requires that is 50
"millions"? I worked in that space for a while and I never saw any
tolerances like that - but that does not say much. I believe that even the
space shuttle does not demand tolerances that close - but I really do not
know.

Jet engine parts, microwave wave guides, thousands of things. Most of
which I was not cleared to know what they were when I ran into them..
An awful lot of optical stuff is that or more.

Shrug. And a lot of that stuff I figured would be good at
+0/- .001...but..the specs...

As the truism goes...the more zeros you add to the right of the
decimal point...you multiply the cost by a factor of 5-10


Half a thou? (NOBODY says 50 millionths!)

Half a thou isnt 50 millionths. Its only 5 tenths.
Half a tenth..is 50 millionths.

I really hate to get in to this with all of you exactimundo types with
all your close tolerances but "Half a thou is not 5 tenths"

..001 / 2 =.0005 not .5

and half a tenth is not 50 millionths,

..1 / 2 =.25

Or maybe you guys are using a different kind of math....

On 11/24/2013 8:15 AM, Lloyd E. Sponenburgh wrote:
"Jim Wilkins" fired this volley in news:l6suie$fts
:

What is the tolerance for hydraulic spool valves?

A few tenths, usually. And then, only that close when they pay really
close attention to the coefficients of expansion of the spool and the
frame.

Remember that there has to be enough room between parts to develop a film
of lubricating (and sealing) oil, or they don't work.

There's an old (perhaps true) mythos about when Royce/Rolls first
introduced an automatic transmission. They were adamant about making it
to much tighter tolerances than "consumer" trannies, because they
demanded the utmost in 'quality'. Then they discovered that the valve
body and shuttles HAD to be sloppy in order to work at all. G

Lloyd


Many years ago my shop foreman, that at one time lived in England and
worked for Rolls, claimed that the engines used no head gaskets, the
heads were bolted straight onto the blocks.

On 11/24/2013 12:15 AM, wrote:
On Sat, 23 Nov 2013 23:47:12 -0600, Leon lcb11211@swbelldotnet
The back of the cabinets have face frames also. The back face frames
however are assembled with lap joints that join with the rabbets on the
inside edges. The center back stiles are part of the back face frame
and it too has rabbets. The rabbets are 1/2" deep and 1/2" wide. The
back panels fit in to the rabbets from the back side.

No need to send me a Sketchup file, I understand perfectly. But, your
explanation leads me to a few more questions. Are the back face frames
for support, visualization, a combination of both or maybe something
else?

The back frames are for all of the above. They make the piece into more
of a piece of furniture than simply a cabinet with a face frame, which
is how a lot of furniture is built. Having a back face frames gives the
sides symmetry and allows me to add other touches should I need to
decorate the sides more. And they add a lot of support and strength to
the backs of the cabinet. If there is a wide adjustable shelf the back
center stiles along with the front center stiles give me an additional
spot to add adjustable support pins. Marys bookcases are approximately
10' wide total. IIRC the center section is about 48" wide and the tall
outer cases are 36" wide. The goal with Mary's bookcases was to build
cases that she could load up with books and not see any sag in the
shelves. Mission accomplished.





And, how are you fastening the back panels? If the back face frames
are 3/4" initially, removing a rabbet of 1/2" leaves only 1/4". I'm
guessing some type of glazier points or something similar?


The back face frame rabbets are actually 1/4" deep not 1/2" as I
misstated above. They are 1/2" wide. And the back face frames like the
front face frames receive the top, side, and bottom panels with 1/4"
deep by 3/4" wide dado's and grooves. I typically use a 5/8" inch #6
pan head screw to attach the backs for easily removal. Sometimes a
mirror is call for instead of a solid panel.

Bottom and top panels fit into dado's at the bottom and top of the side
panels.

Dry fit prior to gluing the cabinets will stand up on their own.





Thanks.

On Sat, 23 Nov 2013 23:01:06 -0600, Gordon Shumway
wrote:

On Sat, 23 Nov 2013 23:33:15 -0500, "Mike Marlow"
wrote:

Gunner Asch wrote:


Ayup...aerospace requires 50 millions or half 10ths all the time.

Which is damned hard to do with machines that hold +/- 2 tenths


One might think it is impossible to do with repeatability and assurance.

So - I am curious - what is it that aerospace requires that is 50
"millions"? I worked in that space for a while and I never saw any
tolerances like that - but that does not say much. I believe that even the
space shuttle does not demand tolerances that close - but I really do not
know.

Likely jet engine parts but certainly not the galley cabinets.

Knowing nothing about aerospace I am willing to hazard a guess. I
presume the space shuttle does not require tolerances anywhere near
MILLIONTHS of an inch but I presume the shuttle's trajectory
calculations would. I imagine that a rounding error would be the
difference between a successful orbit or crashing into Homer Simpson's
house in Springfield.

Perhaps if the shuttle couldn't alter its trajectory (but orbital
mechanics aren't known to that precision, anyway - three body
problem). However, it does (did) have engines intended to make such
corrections.

On 11/24/2013 6:55 AM, wrote:
On Saturday, 23 November 2013 21:17:28 UTC, Leon wrote:

While we are bragging,

http://www.flickr.com/photos/lcb1121...7630857421932/

And with the exception of a couple of older pieces I have built all of
these in the last three years and after I converted to Sketchup.
AFWIW all joint details were drawn in Sketchup.


Hi Leon,

What is this:

http://www.flickr.com/photos/lcb1121...7630857421932/

??

I assume it's something to do with sewing due to the cotton reel, but
my tiny mind can't imagine what the whole thing would be for (which isn't
a shock, really!)

Cheers.



That is a dedicated sewing machine that is know as a Long Arm Sewing
Machine. It's sole purpose is to attach the top, inner padded layer,
and bottom parts of a quilt together.

The three sections of the quilt pieces are rolled up on to the front two
poles then through the needle and foot of the machine then behind and up
the back bottom pole and would up on the back upper take up pole.

The machine rolls back and forth on the tracks, 11' wide, and it moves
forward approximately 12~14". With this X,Y movement the operator can
sew a freehand or laser guided pattern through all layers of the quilt
left to right or right to left 12~14 deep at a time. Once a pass is
made the sewn portion of the quilt is roll up on the upper back take up
real and a new row of sewing begins.

On Sunday, 24 November 2013 16:53:25 UTC, Leon wrote:

That is a dedicated sewing machine that is know as a Long Arm Sewing
Machine. It's sole purpose is to attach the top, inner padded layer,
and bottom parts of a quilt together.

The three sections of the quilt pieces are rolled up on to the front two
poles then through the needle and foot of the machine then behind and up
the back bottom pole and would up on the back upper take up pole.

The machine rolls back and forth on the tracks, 11' wide, and it moves
forward approximately 12~14". With this X,Y movement the operator can
sew a freehand or laser guided pattern through all layers of the quilt
left to right or right to left 12~14 deep at a time. Once a pass is
made the sewn portion of the quilt is roll up on the upper back take up
real and a new row of sewing begins.


Thanks for the explanation Leon, much appreciated. I'd wondered how they
do that sort of thing!

Leon lcb11211@swbelldotnet fired this volley in news:6sCdncLoho-
:

Or maybe you guys are using a different kind of math....

Or MAYBE we work to such small tolerances that "tenths" in machining jargon
means "tenth of a thousanth".

Lloyd

Leon lcb11211@swbelldotnet fired this volley in news:j-
:

Many years ago my shop foreman, that at one time lived in England and
worked for Rolls, claimed that the engines used no head gaskets, the
heads were bolted straight onto the blocks.

My Deutz tractor is the same way. Precise construction. The heads are
made with a shallow taper joint, and they bolt directly onto the cylinders
(air-cooled, so the cylinders bolt TO the block, rather than being a part
of it).

Lloyd

"Lloyd E. Sponenburgh" lloydspinsidemindspring.com fired this volley in
. 3.70:

thousanth".

or thousandth... duh.
L

"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message
. 3.70...
Leon lcb11211@swbelldotnet fired this volley in news:6sCdncLoho-
:

Or maybe you guys are using a different kind of math....

Or MAYBE we work to such small tolerances that "tenths" in machining
jargon
means "tenth of a thousanth".

Lloyd

"Tenth" could be 1/10 of an inch, foot, mile, or in this case Mil:
http://www.thefreedictionary.com/mil
"a unit of length equal to one thousandth of an inch"

A mil (or mill) is also 1/1000 of a dollar:
http://en.wikipedia.org/wiki/Mill_(currency)
"Additionally, in finance the term is spelled "mil".

Under "Fiction" notice that Japanese isn't the only language with a
word for 10,000.

jsw

On 11/24/2013 11:49 AM, Lloyd E. Sponenburgh wrote:
Leon lcb11211@swbelldotnet fired this volley in news:6sCdncLoho-
:

Or maybe you guys are using a different kind of math....

Or MAYBE we work to such small tolerances that "tenths" in machining jargon
means "tenth of a thousanth".

Lloyd



that would splain it

wrote:

Likely jet engine parts but certainly not the galley cabinets.


I'm still wondering about even the jet engine parts. Maybe those parts that
are laser cut, but I just cannot imagine machined parts to those tolerances.
I could be wrong as I said in the beginning, but if I am, I'm suitably
impressed.



Perhaps if the shuttle couldn't alter its trajectory (but orbital
mechanics aren't known to that precision, anyway - three body
problem). However, it does (did) have engines intended to make such
corrections.

And my experience with guided missles - which is very significant, makes me
believe they do not attempt to make corrections to this degree, even with
the shuttle. Hell, a gust of wind during flight would screw those
tolerances up by orders of magnatude.

--

-Mike-

On 11/24/2013 12:45 AM, Gunner Asch wrote:
On Sun, 24 Nov 2013 00:20:47 -0600,
wrote:

On 11/24/2013 12:00 AM, Gunner Asch wrote:
On Sat, 23 Nov 2013 23:33:15 -0500, "Mike Marlow"
wrote:

Gunner Asch wrote:


Ayup...aerospace requires 50 millions or half 10ths all the time.

Which is damned hard to do with machines that hold +/- 2 tenths


One might think it is impossible to do with repeatability and assurance.

Hardly impossible. It happens many thousands..hundreds of thousands
of parts a day.

So - I am curious - what is it that aerospace requires that is 50
"millions"? I worked in that space for a while and I never saw any
tolerances like that - but that does not say much. I believe that even the
space shuttle does not demand tolerances that close - but I really do not
know.

Jet engine parts, microwave wave guides, thousands of things. Most of
which I was not cleared to know what they were when I ran into them..
An awful lot of optical stuff is that or more.

Shrug. And a lot of that stuff I figured would be good at
+0/- .001...but..the specs...

As the truism goes...the more zeros you add to the right of the
decimal point...you multiply the cost by a factor of 5-10


Half a thou? (NOBODY says 50 millionths!)

Half a thou isnt 50 millionths. Its only 5 tenths.
Half a tenth..is 50 millionths.


Half a TENTH.
I woke up in the middle of the night and realized I wrote that wrong.

"Mike Marlow" fired this volley in
:


I'm still wondering about even the jet engine parts. Maybe those
parts that are laser cut, but I just cannot imagine machined parts to
those tolerances. I could be wrong as I said in the beginning, but if
I am, I'm suitably impressed.

Not for nothin', but precision bearings are machined to 10 microinches all
the time -- and they're CHEAP!

Lloyd

On Sun, 24 Nov 2013 11:49:56 -0600, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Leon lcb11211@swbelldotnet fired this volley in news:6sCdncLoho-
:

Or maybe you guys are using a different kind of math....

Or MAYBE we work to such small tolerances that "tenths" in machining jargon
means "tenth of a thousanth".

Lloyd

Ayup.

..0001 = 1/10th of a thousandth of an inch
..00005 = 50 millionths

Ive micrometers that measure that closely. After that..I need a CMM
to properly measure parts.

Gunner

__
"A human being should be able to change a diaper, plan an invasion,
butcher a hog, conn a ship, design a building, write a sonnet,
balance accounts, build a wall, set a bone, comfort the dying,
take orders, give orders, cooperate, act alone, solve equations,
analyze a new problem, pitch manure, program a computer,
cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects."
- Heinlein

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On Sun, 24 Nov 2013 13:07:07 -0500, "Jim Wilkins"
wrote:


"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message
.3.70...
Leon lcb11211@swbelldotnet fired this volley in news:6sCdncLoho-
:

Or maybe you guys are using a different kind of math....

Or MAYBE we work to such small tolerances that "tenths" in machining
jargon
means "tenth of a thousanth".

Lloyd

"Tenth" could be 1/10 of an inch, foot, mile, or in this case Mil:
http://www.thefreedictionary.com/mil
"a unit of length equal to one thousandth of an inch"

It certainly could be. But..in machining..its got a very specific
meaning. .0001"


A mil (or mill) is also 1/1000 of a dollar:
http://en.wikipedia.org/wiki/Mill_(currency)
"Additionally, in finance the term is spelled "mil".

Under "Fiction" notice that Japanese isn't the only language with a
word for 10,000.

jsw


__
"A human being should be able to change a diaper, plan an invasion,
butcher a hog, conn a ship, design a building, write a sonnet,
balance accounts, build a wall, set a bone, comfort the dying,
take orders, give orders, cooperate, act alone, solve equations,
analyze a new problem, pitch manure, program a computer,
cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects."
- Heinlein

---
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On Sun, 24 Nov 2013 08:37:21 -0500, "Mike Marlow"
wrote:

Jim Wilkins wrote:
"Mike Marlow" wrote in message
...
Gunner Asch wrote:
Ayup...aerospace requires 50 millions or half 10ths all the time.
Which is damned hard to do with machines that hold +/- 2 tenths

One might think it is impossible to do with repeatability and
assurance.

So - I am curious - what is it that aerospace requires that is 50
"millions"? I worked in that space for a while and I never saw any
tolerances like that - but that does not say much. I believe that
even the space shuttle does not demand tolerances that close - but I
really do not know.
-Mike-


What is the tolerance for hydraulic spool valves?

You forced me to look that one up. A quick look seems to indicate that
tolerances are around 5 ten thousanths of an inch.

..0005?

5 tenths in other words. And those are common as dirt.


__
"A human being should be able to change a diaper, plan an invasion,
butcher a hog, conn a ship, design a building, write a sonnet,
balance accounts, build a wall, set a bone, comfort the dying,
take orders, give orders, cooperate, act alone, solve equations,
analyze a new problem, pitch manure, program a computer,
cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects."
- Heinlein

---
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On Sun, 24 Nov 2013 09:05:11 -0500, "Jim Wilkins"
wrote:

"Mike Marlow" wrote in message
...
Jim Wilkins wrote:

What is the tolerance for hydraulic spool valves?

You forced me to look that one up. A quick look seems to indicate
that tolerances are around 5 ten thousanths of an inch.
-Mike-

I did too. The last post claims .000025" to .000040" clearance for
aircraft valves.
http://www.practicalmachinist.com/vb...arance-232520/

jsw

ayup.

Gunner

__
"A human being should be able to change a diaper, plan an invasion,
butcher a hog, conn a ship, design a building, write a sonnet,
balance accounts, build a wall, set a bone, comfort the dying,
take orders, give orders, cooperate, act alone, solve equations,
analyze a new problem, pitch manure, program a computer,
cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects."
- Heinlein

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"Lloyd E. Sponenburgh" wrote:

"Mike Marlow" fired this volley in
:


I'm still wondering about even the jet engine parts. Maybe those
parts that are laser cut, but I just cannot imagine machined parts to
those tolerances. I could be wrong as I said in the beginning, but if
I am, I'm suitably impressed.

Not for nothin', but precision bearings are machined to 10 microinches all
the time -- and they're CHEAP!


How many people reading this have ever done any sort
of work close to that precision?

This is what you claimed.
"We work to tenths of thou"

jim fired this volley in news:FpGdnZc-
:

How many people reading this have ever done any sort
of work close to that precision?

With a short, stiff cutter and slow feeds, I can work to half a tenth all
day. Certainly, that's not 10 micro-inches, but I can buy $7.00 bearings
from McMaster that meet that spec.

I can't, because of the age and condition of my machines. But my CAD and
CAM work to those tolerances and below.

Somebody said in this thread that some CAD worked to an internal
precision of 0.0001"... hell... my cheapest CAM software works to seven
digits! G

Ten micro-inches is not an amazing feat with new (but fairly specialized)
equipment.

Lloyd

"Lloyd E. Sponenburgh" wrote:

jim fired this volley in news:FpGdnZc-
:

How many people reading this have ever done any sort
of work close to that precision?

With a short, stiff cutter and slow feeds, I can work to half a tenth all
day.

I can work to a tenth with floppy piece of sandpaper, but that
is a little different than creating a CAD model and then
manufacturing the part to within a tenth of the model dimensions.


Certainly, that's not 10 micro-inches, but I can buy $7.00 bearings
from McMaster that meet that spec.

And how many of the 'we who work to a tenth'
could make that bearing?


I can't, because of the age and condition of my machines. But my CAD and
CAM work to those tolerances and below.

So can Sketchup. It uses floating point data which means it
can describe geometry about 1 million times more precise than
anything you could make.


Somebody said in this thread that some CAD worked to an internal
precision of 0.0001"... hell... my cheapest CAM software works to seven
digits! G

One would hope so for most calculations. However it is kind of
pointless to pump out G-code that is lot more precise than the
machine tool positioning capability.


Ten micro-inches is not an amazing feat with new (but fairly specialized)
equipment.

People have been making things flat or round to that level of
precision for ages.


Lloyd

jim fired this volley in
:

People have been making things flat or round to that level of
precision for ages.


Yup... I can make a piece of glass flat to about three angstroms by hand.

But your comments to the negative don't bear on the discussion. The
discussion never was "how many of 'us' could do it"; But is it a
realizable and realistic degree of precision?

Yes, it is... even with the sort of equipment I use (albeit newer and in
better condition).

I'm not working with a table-top Tormach, and do this professionally.
But even a lot of amateurs have older high-end industrial equipment. It
sells for scrap value, if one is willing to do the work to rescue it and
upgrade the electronics.

I just had an 'amateur/recreational' machinist friend buy a full-up Fanuc
slant-bed turning center with 4th axis, 12' bar feeder, and live tooling
(+ATC)... With a little TLC and good insert tooling, that machine will do
sub-tenths work -- in his garage!

Lloyd

Lloyd

Richard wrote:
On 11/24/2013 12:45 AM, Gunner Asch wrote:
On Sun, 24 Nov 2013 00:20:47 -0600,
wrote:

On 11/24/2013 12:00 AM, Gunner Asch wrote:
On Sat, 23 Nov 2013 23:33:15 -0500, "Mike Marlow"
wrote:

Gunner Asch wrote:


Ayup...aerospace requires 50 millions or half 10ths all the time.

Which is damned hard to do with machines that hold +/- 2 tenths


One might think it is impossible to do with repeatability and
assurance.

Hardly impossible. It happens many thousands..hundreds of
thousands of parts a day.

So - I am curious - what is it that aerospace requires that is 50
"millions"? I worked in that space for a while and I never saw
any tolerances like that - but that does not say much. I believe
that even the space shuttle does not demand tolerances that close
- but I really do not know.

Jet engine parts, microwave wave guides, thousands of things. Most of
which I was not cleared to know what they were when I ran
into them.. An awful lot of optical stuff is that or more.

Shrug. And a lot of that stuff I figured would be good at
+0/- .001...but..the specs...

As the truism goes...the more zeros you add to the right of the
decimal point...you multiply the cost by a factor of 5-10


Half a thou? (NOBODY says 50 millionths!)

Half a thou isnt 50 millionths. Its only 5 tenths.
Half a tenth..is 50 millionths.


Half a TENTH.
I woke up in the middle of the night and realized I wrote that wrong.

Not sure what you were trying to correct Richard. Look at it again - you
still have it wrong.

--

-Mike-

On Sun, 24 Nov 2013 13:22:22 -0600, Richard
wrote:

On 11/24/2013 12:45 AM, Gunner Asch wrote:
On Sun, 24 Nov 2013 00:20:47 -0600,
wrote:

On 11/24/2013 12:00 AM, Gunner Asch wrote:
On Sat, 23 Nov 2013 23:33:15 -0500, "Mike Marlow"
wrote:

Gunner Asch wrote:


Ayup...aerospace requires 50 millions or half 10ths all the time.

Which is damned hard to do with machines that hold +/- 2 tenths


One might think it is impossible to do with repeatability and assurance.

Hardly impossible. It happens many thousands..hundreds of thousands
of parts a day.

So - I am curious - what is it that aerospace requires that is 50
"millions"? I worked in that space for a while and I never saw any
tolerances like that - but that does not say much. I believe that even the
space shuttle does not demand tolerances that close - but I really do not
know.

Jet engine parts, microwave wave guides, thousands of things. Most of
which I was not cleared to know what they were when I ran into them..
An awful lot of optical stuff is that or more.

Shrug. And a lot of that stuff I figured would be good at
+0/- .001...but..the specs...

As the truism goes...the more zeros you add to the right of the
decimal point...you multiply the cost by a factor of 5-10


Half a thou? (NOBODY says 50 millionths!)

Half a thou isnt 50 millionths. Its only 5 tenths.
Half a tenth..is 50 millionths.


Half a TENTH.
I woke up in the middle of the night and realized I wrote that wrong.

(Grin)


__
"A human being should be able to change a diaper, plan an invasion,
butcher a hog, conn a ship, design a building, write a sonnet,
balance accounts, build a wall, set a bone, comfort the dying,
take orders, give orders, cooperate, act alone, solve equations,
analyze a new problem, pitch manure, program a computer,
cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects."
- Heinlein

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On Sun, 24 Nov 2013 14:14:00 -0500, "Mike Marlow"
wrote:

wrote:

Likely jet engine parts but certainly not the galley cabinets.


I'm still wondering about even the jet engine parts. Maybe those parts that
are laser cut, but I just cannot imagine machined parts to those tolerances.
I could be wrong as I said in the beginning, but if I am, I'm suitably
impressed.



Perhaps if the shuttle couldn't alter its trajectory (but orbital
mechanics aren't known to that precision, anyway - three body
problem). However, it does (did) have engines intended to make such
corrections.

And my experience with guided missles - which is very significant, makes me
believe they do not attempt to make corrections to this degree, even with
the shuttle. Hell, a gust of wind during flight would screw those
tolerances up by orders of magnatude.

Guided missiles and rockets are two different things. Nuclear
missiles are "ballistic" (even they are steerable), rockets, not so
much. You can't orbit an object in a ballistic trajectory. They
*have* be able to correct their trajectory. Not only does/did the
Shuttle have aerodynamic surfaces and steerable main engines for
atmospheric corrections, it has/had OMS engines and thrusters fore,
and aft, for extra atmospheric corrections.

On Sun, 24 Nov 2013 15:16:24 -0600, jim
wrote:



"Lloyd E. Sponenburgh" wrote:

jim fired this volley in news:FpGdnZc-
:

How many people reading this have ever done any sort
of work close to that precision?

With a short, stiff cutter and slow feeds, I can work to half a tenth all
day.

I can work to a tenth with floppy piece of sandpaper, but that
is a little different than creating a CAD model and then
manufacturing the part to within a tenth of the model dimensions.


Certainly, that's not 10 micro-inches, but I can buy $7.00 bearings
from McMaster that meet that spec.

And how many of the 'we who work to a tenth'
could make that bearing?


I can't, because of the age and condition of my machines. But my CAD and
CAM work to those tolerances and below.

So can Sketchup. It uses floating point data which means it
can describe geometry about 1 million times more precise than
anything you could make.


Somebody said in this thread that some CAD worked to an internal
precision of 0.0001"... hell... my cheapest CAM software works to seven
digits! G

One would hope so for most calculations. However it is kind of
pointless to pump out G-code that is lot more precise than the
machine tool positioning capability.


Ten micro-inches is not an amazing feat with new (but fairly specialized)
equipment.

People have been making things flat or round to that level of
precision for ages.

Flat and round (spherical) are trivial problems and as you note it's
been done for ages, at least since the middle ages. Other shapes are
more difficult, as is size.

On Sun, 24 Nov 2013 17:10:43 -0500, "Mike Marlow"
wrote:

Richard wrote:
On 11/24/2013 12:45 AM, Gunner Asch wrote:
On Sun, 24 Nov 2013 00:20:47 -0600,
wrote:

On 11/24/2013 12:00 AM, Gunner Asch wrote:
On Sat, 23 Nov 2013 23:33:15 -0500, "Mike Marlow"
wrote:

Gunner Asch wrote:


Ayup...aerospace requires 50 millions or half 10ths all the time.

Which is damned hard to do with machines that hold +/- 2 tenths


One might think it is impossible to do with repeatability and
assurance.

Hardly impossible. It happens many thousands..hundreds of
thousands of parts a day.

So - I am curious - what is it that aerospace requires that is 50
"millions"? I worked in that space for a while and I never saw
any tolerances like that - but that does not say much. I believe
that even the space shuttle does not demand tolerances that close
- but I really do not know.

Jet engine parts, microwave wave guides, thousands of things. Most of
which I was not cleared to know what they were when I ran
into them.. An awful lot of optical stuff is that or more.

Shrug. And a lot of that stuff I figured would be good at
+0/- .001...but..the specs...

As the truism goes...the more zeros you add to the right of the
decimal point...you multiply the cost by a factor of 5-10


Half a thou? (NOBODY says 50 millionths!)

Half a thou isnt 50 millionths. Its only 5 tenths.
Half a tenth..is 50 millionths.


Half a TENTH.
I woke up in the middle of the night and realized I wrote that wrong.

Not sure what you were trying to correct Richard. Look at it again - you
still have it wrong.

Blink blink? Say what?

Half a tenth is 50 millionths.


__
"A human being should be able to change a diaper, plan an invasion,
butcher a hog, conn a ship, design a building, write a sonnet,
balance accounts, build a wall, set a bone, comfort the dying,
take orders, give orders, cooperate, act alone, solve equations,
analyze a new problem, pitch manure, program a computer,
cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects."
- Heinlein

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wrote:


People have been making things flat or round to that level of
precision for ages.

Flat and round (spherical) are trivial problems and as you note it's
been done for ages, at least since the middle ages.

And there isn't much advantage in having a
CAD model for those shapes.



Other shapes are
more difficult, as is size.

And it is doubtful there is anyone reading this who
is cutting complex shapes from CAD models with precision
held to tenths.