Identifying a binocular thread
news.tplex.com.au
When I told my dad that I'd bought a lathe to keep me
amused in my declining years, he immediately came
up with a bunch of jobs to keep me busy, and one of
these is currently causing me hassles...
He has broken one of the little eye sockets on a set
of binoculars (circa 1970 as best I can recall) and I'm
trying to duplicate the remaining good one.
The inside thread on this piece has a minor diameter
of 26.12 mm as best I can tell, and the pitch is close
to 0.4 mm. I don't have access to the male thread on
the binocs...
Now 0.4 mm is a valid metric pitch, or it could be a
64 tpi imperial thread, but I can't make the diameter
come out as anything particularly meaningful in either
system of units...
Any ideas on what it might be?
I thought that, if I could get an idea of what the thread
should be, I could cut a male thread as a test, and if
the socket threads on it OK I should be able to make
the replacement with the corresponding internal
thread...
Cheers, Dieter.
Steve Strickland
<die...@tplex.com.au> wrote:
In one of the 3 volume set of Amateur Telescope Making by Ingalls
(Scientific American) is an extensive article by a fellow who worked for
the Navy repairing and rebuilding binoculars during WW2. It covers the
lathe setups for rethreading these things as well as a lot of additional
binocular work. It's excellent and inclusive. Sorry, but I can't recall
which volume contained it.
Steve
--
Steve Strickland, Puzzlecraft
st...@puzzlecraft.com
www.puzzlecraft.com
Nick Hull
> The inside thread on this piece has a minor diameter
> of 26.12 mm as best I can tell, and the pitch is close
> to 0.4 mm. I don't have access to the male thread on
> the binocs...
>
> Now 0.4 mm is a valid metric pitch, or it could be a
> 64 tpi imperial thread, but I can't make the diameter
> come out as anything particularly meaningful in either
> system of units...
The thread engagement is so short the pitch does not have to be exact. It
wqould help a LOT if you could get access to the male thread and measure
it with a wire gauge. A lot of these threads were made to wierd
diameters.
--
Free men own guns - slaves don't
http://www.geocities.com/nickhull99
BEAR
Save yourself a lot of grief go out and buy him an nice new Tasco binocular,
the new stuff has so much better optics than the old stuff it's no contest.
Imho.
_-_-bear
--
_-_-bearlabs
http://www.bearlabsUSA.com
- Silver Lightning Interconnects -
jj wade
thread yourself M26 X .4. The .4 part is pretty typical.
"news.tplex.com.au" <die...@tplex.com.au> wrote in message
news:3d3e4c6a$1...@duster.adelaide.on.net...
jj wade
little looking up and the the height of a v for a .4 thread is .35, add that
to your 26.12 and you come to just about 26.5, also a common metric thread
used in optics, so my new and improved guess is a M26.5 X .4 thread.
"jj wade" <produc...@mindspring.com> wrote in message
news:RKA%8.20178$uh7.4637@sccrnsc03...
Ted Edwards
microscopes and telescopes. How sure are you of your 0.4mm?
Ted
PLAlbrecht
"Save yourself a lot of grief go out and buy him an nice new Tasco binocular,
the new stuff has so much better optics than the old stuff it's no contest.
Imho."
What a hoot. For as long as I can remember, this brand has been called
"Trashco." They're Wal-Mart binoculars. Everything they make is Wal-Mart
quality.
Trashco, Bushnell, and the other usual dime-store brands are just about as bad
as any reasonable person would expect.
Pete
Bob May
equivalent new binocs. I do optical work occasionally and those old binocs
were pretty decent. WW2 era binocs will run circles around the new stuff -
they really knew how to do optics by that time and the quality and quality
control were excellent. The Trashco and so forth are doing a price point
and one of the things is that they are for daylight use only. Use them
under dim conditions and the optical quality of them really shows up as
poor. They are light tho.
As to the threading, make a set of threads on a rod and see how good a job
you did. If the binocs are American or older British, the thread standard
will be english while some of the other sources can either be english or
metric. If you only do two or three turns, you can do a lot of adapting of
the threads without problems.
--
Bob May
Global WARMING???
What I want to know is when I can start growing wheat in Greenland again!
PLAlbrecht
under dim conditions and the optical quality of them really shows up as
poor.
Right. Star test for example.
It looks like Trashco has been bought out by Bushnell.
Pete
Gunner
True..not up to the current quality of Nikon, Minolta (my favorite for
the money), Svarwski, etc.
But even Tasco/Bushnell are still miles ahead of the old binocs from 30
yrs ago. And quite cost effective.
Gunner
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Marv Soloff
If you can find them, Russian binox are a very good buy at Walmart/Tasco
prices. Unfortunately, they still have that fish oil smell.
Regards,
Marv
PLAlbrecht
mso...@worldnet.att.net writes:
<< If you can find them, Russian binox are a very good buy at Walmart/Tasco
prices. >>
Yes, so I've heard. Cost-no-object type military surplus. Same with night
vision devices etc.
Pete
Peter Wiley
I have some Bushnell binocs and they're not bad in dim light; good
enough to pick up rabbits at dusk, for example. Better than cheap
Tasco's that's for sure; had a Tasco scope on the rifle that couldn't
pick up rabbits I could see in the binocs so I replaced it with a
Leupold. None of these are close to my Karl Zeiss rubber armoured
binocs, though. OTOH, the Zeiss glasses cost 10X the Bushnells, and
weigh a ton.
Great for bird watching in dim light on the ship, tho.
Peter Wiley
jj wade
"Ted Edwards" <Te...@telus.net> wrote in message
news:3D3EB1...@telus.net...
Norman Yarvin
PLAlbrecht <plalb...@aol.com> wrote:
>>Use them
>>under dim conditions and the optical quality of them really shows up as
>>poor.
>
>Right. Star test for example.
That's mostly for telescopes; ordinary binoculars are too low-powered to
really need it. And when they say "all surfaces coated", they usually
mean it, and that means the light transmission will be okay, unless they
did that cheap marketing trick of coating the objective lenses with a
highly visible reddish ("amber") coating to attract idiots who think that
anything new and flashy must be good.
But even once you get past the cheap marketing tricks, there is an
enormous problem with cheap binoculars: the two halves don't point in the
same direction. You can look through them, and they look bright enough
(unless you fell for ones that only have the outer surfaces
anti-reflection coated) and sharp enough, but something seems odd: the
images from the two eyepieces are hard or impossible to merge together,
and looking through them for long is unpleasant.
The Scientific American Amateur Scientist CD-ROM that we discussed here a
while ago has a spec for how closely binoculars should be aligned:
"The formulas in Donald H. Jacobs' Fundamentals of Optical
Engineering give a tolerance for non-parallelism in 7X
binoculars of only 3.75 minutes of arc for convergence and 1.3
minutes for divergence horizontally and/or vertically."
(For those who got the CD-ROM, it's file amsci01/1954/07/1954-07-fs.html.
For those who didn't, it's now half the price we paid, at:
http://shop1.outpost.com/product/2857334
)
Now 3.75 minutes of arc is about 0.001 radian. That's one part in a
thousand... and it's the looser of the two error bounds! And the
binoculars need to be aligned not just in one position, but in each and
every position as the two halves swing apart to adjust for the distance
between your eyes. This takes precision metalworking; you're not going
to get it for $35, or even $50 -- even though you can get a tolerable
monocular for $15.
--
Norman Yarvin norman...@snet.net
news.tplex.com.au
> At one time 40tpi was a common "instrument" thread. I've seen it on
> microscopes and telescopes. How sure are you of your 0.4mm?
It's pretty rough - I took several sets of measurements (by scraping a
pin across the threads and counting the clicks, and then measuring
the total length of thread as well as I could with a digital vernier.
I know that's pretty agricultural, but I was looking to get an initial size
estimate so I could turn up a trial outside thread and then adjust my
assumption based on the fit I got.
I measured 6 "clicks" over an average distance of 2.42 mm which is
0.40333... mm or 62.97 tpi.
I suppose, though, that my estimate could be 10% or more out. Still,
40 tpi would be pushing it...
Cheers, Dieter.
news.tplex.com.au
> sorry reread the thread and noticed it was an Id you measured, I did a
> little looking up and the the height of a v for a .4 thread is .35, add
that
> to your 26.12 and you come to just about 26.5, also a common metric thread
> used in optics, so my new and improved guess is a M26.5 X .4 thread.
Ah, that's interesting. I'd also (as a very rough estimate) added 0.40 to
26.12 to get 26.52, but the idea that 26.5 might be a standard diameter
had seemed sufficiently implausible that I'd rejected it. Converting to an
imperial gave me an inch plus odd amount, so I also though that was a
bit unlikely. Hence my request for what it might plausibly be.
I'll try threading up some steel to M26.5 X 0.40 and see if it goes on.
I'm aware that the binox are probably not worth the trouble, and my dad
was really just after some bits of plastic with an oversize hole in them
that he could glue in place, but hey, I want to show of some of the tricks
I've been learning at night class!
Many thanks for confirming that M26.5 X 0.40 is plausible and not just
the punchline to a joke!
Cheers, Dieter.
PLAlbrecht
binoculars need to be aligned not just in one position, but in each and
every position as the two halves swing apart to adjust for the distance
between your eyes. This takes precision metalworking; you're not going
to get it for $35, or even $50 -- even though you can get a tolerable
monocular for $15.
Norman, sorry to say your advice came to late to help Marty Feldman...
:-)
(Good points on exactly how you get what you pay for).
Pete
Gary Coffman
>I have some Bushnell binocs and they're not bad in dim light; good
>enough to pick up rabbits at dusk, for example. Better than cheap
>Tasco's that's for sure; had a Tasco scope on the rifle that couldn't
>pick up rabbits I could see in the binocs so I replaced it with a
>Leupold. None of these are close to my Karl Zeiss rubber armoured
>binocs, though. OTOH, the Zeiss glasses cost 10X the Bushnells, and
>weigh a ton.
I haven't found any Tasco branded binocs that I like. But Bushnell does
make at least one good binocular. Their Custom Compact is really quite
good. I had a chance to trial them against a number of brand name high
end compacts, and they fared very well.
For their size, they are quite bright and sharp. The focusing mechanism
is smooth and precise, and falls naturally to hand. They work well with
eyeglasses too. I can use them for long periods without eye fatigue.
To me, that's a key test of a binocular.
They're also rugged enough to have survived a dozen years of hard
field use. I've had brand name riflescopes that failed under conditions
that the Bushnells shrugged off.
Gary
Steve Strickland
<norman...@snet.net> wrote:
In the Scientific American book I cited earlier it was noted that
virtually no commercial binocular was made to the highest precision. One
of the main problems was making the two optical paths parallel through the
entire rotation. The machining procedure for correcting this is given.
The star test is a good one for detecting astigmatism caused by misaligned
or tilted primary optics and also for testing for non-perfect prism
geometry. The technique for polishing the prisms to the correct geometry
is given in the article as well as the optical alignment procedures.
Forming a perfectly round set of diffraction rings with the correct energy
distribution while viewing a bright point source of light both inside and
outside of focus is a quite sensitive test. Virtually no commercial
binoculars will pass it. However, American and Japanese WW2 naval
binoculars are known to be amongst the very best ever made. These were
mostly versions that had been rebuilt in the naval optical shops. Both
navies had seriously dedicated experts.
All of the commercial binoculars today would benefit from a careful
binocular tuneup.
Steve Rayner
Big Bear. I bought a pair of 11 X 80 binoculars from a vendor for a bit over
$100 US. It says Celestial Innovations on them, who knows who made them!
They are good! At the star party, several people compared them with high end
products. My cheapos let more light through, and have just as sharp an
image. They have independent focusing like the old Navy binoculars.
--
Steve Rayner.
"PLAlbrecht" <plalb...@aol.com> wrote in message
news:20020724212736...@mb-mr.aol.com...
Jeffry Johnston
: But Bushnell does make at least one good binocular.
I never found them! :)
At walmart I did find some china made stamped "RedField" that were
worth buying ~$90. Green lense coatings like the better scopes have.
: I can use them for long periods without eye fatigue.
: To me, that's a key test of a binocular.
: Gary
That's the most important test for sure but my first test is to check
focus from edge to edge of field against the center. The redfields
were excellent and all the rest were junk like toys from cracker jacks.
Even the higher priced ones they carry. :/
I like to cut my bi-noculars in half. I'm weird, you knew that right?
They fit the glove compartment and pocket better and what I found is a
half a bi-nocular is better than the full sized one you didn't bring. ;)
You want to fix the old ones and that's cool, hope it turns out to be
something you can show off. :) I would... cut them in half and use the
loose eye piece "backwards" like a jeweler's loop. The rest wouldn't go
to waste either, right? :)
Alvin in AZ
PLAlbrecht
Green???
>>I like to cut my bi-noculars in half.
Heathen. Suggest you donate un-needed eye to organ bank.
>>what I found is a
half a bi-nocular is better than the full sized one you didn't bring. ;)
(Psst... also sold as.. a MONOCULAR).
Pete
Ted Edwards
Father. These are pretty old so I can't say anything about their
quality today. I can *say* that these are amongst the nicest binoculars
I've ever used especially in a vehicle - boat, plane, car. I suspect a
large part of this later property is due to the wide angle.
Ted
Gary Coffman
>I haven't found any Tasco branded binocs that I like. But Bushnell does
>make at least one good binocular. Their Custom Compact is really quite
>good. I had a chance to trial them against a number of brand name high
>end compacts, and they fared very well.
A bit of web browsing shows that the Custom Compact is now marketed
under the Bausch & Lomb brand name, which Bushnell apparently now
owns.
Gary
news.tplex.com.au
> At one time 40tpi was a common "instrument" thread. I've seen it on
> microscopes and telescopes. How sure are you of your 0.4mm?
Well, I have to admit that I was seriously over-confident in my
previous statement - I "painted" the ridges of the thread with
a silver marker pen and then carefully examined the threads
and a thread guage under a strong magnifier. It looks like
the thread is a close match to 0.6 mm, not 0.4 mm, which of
course means that 40 tpi or 42 tpi might be a reasonable
match also - within 5% or so, which is certainly possible as I
have only four turns to work with.
It's seriously difficult to get a good measurement of an inside
thread this small, especially on black plastic and with ageing
eyes!
If it's 40, do you have a suggestion as to what the nominal
diameter might be?
Looks like I'll definitely have to cut one or more male test
pieces...
Cheers, Dieter.
Neil Ellwood
And a small telescope ( of equivalent power) is usually smaller.
--
Neil
Drop cat to reply
Pete Somebody
> If you can find them, Russian binox are a very good buy at
> Walmart/Tasco prices. Unfortunately, they still have that fish
> oil smell.
Wife got me an 8" Russian navy surplus compass in gimbals and an
oak box. The thing is built right (except it's got an O where
the E should be).
--
Pete Somebody http://artfulbodger.net/
Why use differential calculus when you can guess?
-- Dave Fogg
PLAlbrecht
oak box. The thing is built right (except it's got an O where
the E should be).
Possibly East German? Or made for German-speaking market? (Nord-Süd-West-Ost)
Because Russian for "north" begins with C, south with I, east with B, west with
3. (Or Cyrillic stuff that looks like that but which I can't otherwise type
in).
Pete
Pete Somebody
>> Wife got me an 8" Russian navy surplus compass in gimbals and
>> an oak box. The thing is built right (except it's got an O
>> where the E should be).
>
> Possibly East German? Or made for German-speaking market?
> (Nord-Sud-West-Ost)
>
> Because Russian for "north" begins with C....
Actually, I wondered about that. I know enough German to know
that East = Ost, but don't know any Russian. Can't think of any
reason why a Russian compass would have German markings ... hmm.
Nice compass in any case. Now I just need to build a boat to put
it in.
boris beizer
news:ahs179$rgj$1...@ceilidh.d-and-d.com...
> PLAlbrecht <plalb...@aol.com> wrote:
>
> Actually, I wondered about that. I know enough German to know
> that East = Ost, but don't know any Russian. Can't think of any
> reason why a Russian compass would have German markings ... hmm.
Possible explanation. When the Russians conquered (East) Germany at the end of
WWII, they took back to Russia everything that wasn't an integral part of a 10
ton concrete block -- and some of those too. Doorknobs, hinges, toilets, ships,
aircraft, and probably every marine compass in East Germany. I've got a WWII
US ships chronometer only a few years ago -- A compass in Russia from that era
isn't unlikely. For all you know, they could have stripped out the factory that
made the compasses and silk-screens for the dials were in German -- didn't have
the technology to make equally good ones in Russian?
> Nice compass in any case. Now I just need to build a boat to put it in.
That's if you're in to traditional compasses. I hate them things. I much
prefer my Suunto's with the built-in inclinometer -- or if I had power on
board, a modern flux gate compass. I helmed the Californian on one trip (big
traditional schooner). Had a totally traditional compass with a white light
instead of a red light. Couldn't steer by it worth a damn at night. One glance
at the compass and for the next ten minutes there was this greenish compass rose
up in the air, in whatever direction you looked.
Boris
--
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TEL: 215-572-5580
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Pete Somebody
> I've got a WWII US ships chronometer only a few years ago...
Wow. Now that would be worth having.
>> Nice compass in any case. Now I just need to build a boat to
>> put it in.
>
> That's if you're in to traditional compasses.
Just the thing for a steam launch. Old tech. As a practical
matter it won't actually see much use: it's not as if I'll be
cruising to Bermuda in the thing.
> Had a totally traditional compass with a white light instead of
> a red light.
That is silly. I knew a delivery captain who kept red nail
polish handy for fixing white binnacle lights. Inelegant, but it
worked.
boris beizer
> boris beizer <bbe...@sprintmail.com> wrote:
>
> > I've got a WWII US ships chronometer only a few years ago...
>
> Wow. Now that would be worth having.
More properly, a "boat" chronometer. "Mark I Boat Clock - Property of US
NAVY - # 7068, 1942" -- a gift from the son of a friend of mine. His father
liberated it from a big US Navy Landing craft. Still keeps excellent time -- if
I remember to wind it every 8 days or so. I have no idea what it is worth --
it will stay in the family for generations to come -- I hope.
> Just the thing for a steam launch.
Fits the period -- however, I doubt that many steam launches had compasses of
any kind.
> it's not as if I'll be cruising to Bermuda in the thing.
Certainly not in a steam launch.
> > Had a totally traditional compass with a white light instead of
> > a red light.
>
> That is silly. I knew a delivery captain who kept red nail
> polish handy for fixing white binnacle lights. Inelegant, but it worked.
Couldn't have done that if I wanted to -- they'd have heaved me overboard.
However, there was a really good upside to helming with that compass at night.
It forced me to learn to steer by a star -- which is really much better because
you have your eyes up and out front where they belong instead of below, glued to
the compass. Steering is smoother too. Sometimes traditional stuff has an
upside -- [METAL CONTENT]>>> as all us non-CNC machinists appreciate.
Jack Erbes
>More properly, a "boat" chronometer. "Mark I Boat Clock - Property of US
>NAVY - # 7068, 1942" -- a gift from the son of a friend of mine. His father
>liberated it from a big US Navy Landing craft. Still keeps excellent time -- if
>I remember to wind it every 8 days or so. I have no idea what it is worth --
>it will stay in the family for generations to come -- I hope.
Let me guess, it is in a waterproof, black phenolic case with a water
proof cover on the front that could be opened for winding or
adjusting. And it rings no bells.
The landing craft was a boat (LCU, LCM, etc.), the thing that hauled
all the landing craft around was a ship (LST, LPD, LPH, etc.). The
time honored dictum was that it had to be commissioned and have a name
to be a ship. Unless, of course, it was a submarine and then it could
be called a boat anyway.
But one clearly irrefutable rule was that not just anybody could wind
or adjust the clock. If you were the Chief that had the little
winding key on your key chain for the clock in your work area, you
were one pretty important dude.
We Cryptologic Technicians had the equipment and were smart enough to
get our own time ticks (from WWV or RID) but the rest of them had to
call Radio Central.
Jack Erbes in Ellsworth, Maine, USA (jac...@midmaine.com)
(formerly ja...@vom.com, either email address will work for the foreseeable future)
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Pete Somebody
> I have no idea what it is worth -- it will stay in the family
> for generations to come -- I hope.
Yes, let's hope so. My grandfather's chronometer and barometer
are among our family's treasures, never to be let go.
>> Just the thing for a steam launch.
>
> Fits the period -- however, I doubt that many steam launches
> had compasses of any kind.
True. With the fogs and heavy thunderstorms where I live,
though, I won't go on the water without one.
> However, there was a really good upside to helming with that
> compass at night. It forced me to learn to steer by a star....
You might enjoy the book "We, The Navigators," by David Lewis.
It's about traditional Polynesian navigation, interesting for
historical and practical reasons. Much discussion of steering by
star and by wave. Lewis has written some good stuff. (ObMetal:
circumnavigated Antarctica in a steel boat.)
Nick Mueller
> Can't think of any reason why a Russian compass would have German markings
> ... hmm.
During the cold war and until the fall of "the wall" Russia (and
East-Germany) made many things*) that were sold in (for that time)
West-Germany. The only way to get hard currency.
*) from lathes to oszilloscopes over tv-sets to cameras and watches.
Nick
--
Never use force, just go and get a bigger hammer.
boris beizer
"Jack Erbes" <jac...@midmaine.com> wrote in message
news:i8p3kuorqbmau15gq...@4ax.com...
> On Fri, 26 Jul 2002 19:39:52 GMT, "boris beizer"
>
> proof cover on the front that could be opened for winding or
> adjusting. And it rings no bells.
Painted green, aluminum case, but otherwise 100% correct. I haven't replaced
the long gone rubber o-ring. Figure if my basement water level gets that high,
I'll have more important things to worry about than a wet clock.
> But one clearly irrefutable rule was that not just anybody could wind
> or adjust the clock. If you were the Chief that had the little
> winding key on your key chain for the clock in your work area, you
> were one pretty important dude.
I've looked high and low for a key and have not been able to find an authentic
US-NAVY key, or any other key that fits. I've made my own winder out of square
brass stock -- inelegant, but it works. If anybody has the key -- I'll be happy
to buy it. 0.135 (to fit a 1/8 shaft) will do it.
The business of only the chief or an officer winding the clock dates
back to first use of shipboard chronometers in the late 18th century. Probably
originated with the first Harrison #3 that went into service.
boris beizer
> boris beizer <bbe...@sprintmail.com> wrote:
>
>
> You might enjoy the book "We, The Navigators," by David Lewis.
> It's about traditional Polynesian navigation, interesting for
> historical and practical reasons. Much discussion of steering by
> star and by wave. Lewis has written some good stuff. (ObMetal:
> circumnavigated Antarctica in a steel boat.)
Read that one long ago. Also important and related, is the book "The Last
Navigator" by Steve Thomas (of This Old House fame). Corresponded with Steve
about his book. Steve apprenticed himself to Pialug -- who probably was the
last functional traditional navigator. It is a great navigation system, but
quite complex and probably impossible to master unless you start at age 4 or so.
Steve showed that a good Polynesian navigator using traditional methods was
generally as good a Western navigator using chronometer, sextant, and sight
reduction tables. There is, apparently, some bad blood between Steve Thomas
and David Lewis -- over who had what rights to produce which TV show. Steve is
a world-class sailor, traditional navigator, and world-class restorer of wooden
ships -- which is what he did before "This Old House."
Trevor Jones
Chronometers were used as a time soursce for navigation. On the larger
ships, they would be mounted, below decks, in sets of three(or more) on
gimballed mounts so that they were always able to remain level (for the
most part, anyway). Logs kept track of the winding times, made note of
notable events that could affect the rate (hard maneuvers, sustained
firing of the ships guns,...)
In use, a Deck Watch would be taken to the chronometer(s) and set to
the correct time.This would be taken up on deck where the sextant shot
was taken. This allowed accurate estimation of longditude to be made.
Does your clock chime the watches, or is it time only?
Cheers
Trevor Jones
A lot of Hamilton Model 21 Chronometers have been surplussed out by the
USN in the last decade. Nice units,but without boxes and gimbals. A lot
of these get trashed because they get wound up and run right out of the
storage can. The USN Observatory staff that preserved these, put them
away dry, with the expectaion that the person putting them back into
service would know, and do a proper oiling as part of the reactivation
process.
Jack Erbes
<bbe...@sprintmail.com> wrote:
>Painted green, aluminum case, but otherwise 100% correct. I haven't replaced
>the long gone rubber o-ring. Figure if my basement water level gets that high,
>I'll have more important things to worry about than a wet clock.
>
This is the clock I was thinking of, in this case 1921 model made by
Seth Thomas, they were supplied by other makers also (Chelsea was
another).
http://www.antiqnet.com/texis,rare_pre_wwii,3cc20ca20.html
I must have seen thousands just like it in my time in the Navy. No
Quarterdeck was without one, no office of any importance either. Had
I had any idea that they might be worth what this one is selling for,
I might have "acquired" a few.
And at those prices your's might be worth the cost of an o-ring.
Here is a source for a replacement key:
http://www.frankenmuthclock.com/partsclock.htm
The original keys were supplied with the clocks and were "turnover
items" when people holding them came and went from jobs. On
Quarterdecks the key was generally kept with or near the clock and
every qualified watchstander knew that its presence did not signal an
invitation to casual use.
If an errant watchstander wound the clock out of ignorance or
stupidity, the designated clock winder would notice it when they did
their weekly winding. Worst case, that might precipitate a search for
the culprit ("who ate the Captain's strawberries" comes to mind), but,
at least, you can bet that a reminder would be made in the PDL (Pass
Down Log).
Ahh, the sanctity of Navy journals and logs. There are archives
somewhere with tons of priceless entries that will never see the light
of day again.
Jack Erbes
<t.o....@sympatico.ca> wrote:
<snip>
> A lot of Hamilton Model 21 Chronometers have been surplussed out by the
>USN in the last decade. Nice units,but without boxes and gimbals. A lot
>of these get trashed because they get wound up and run right out of the
>storage can. The USN Observatory staff that preserved these, put them
>away dry, with the expectaion that the person putting them back into
>service would know, and do a proper oiling as part of the reactivation
>process.
>
Interesting reading, thanks. I still have the majority of a 1 pint
can of sperm oil that was bought from Brownells in the 60's by my
father. Gunsmiths liked it for lubricating triggers, and I think I
was told that it was considered ideal for oiling clocks.
Norman Yarvin
PLAlbrecht <plalb...@aol.com> wrote:
>>>I like to cut my bi-noculars in half.
>
>Heathen. Suggest you donate un-needed eye to organ bank.
Nah, it makes sense. His cheap binoculars were so far out of alignment
anyway, that cutting them in half didn't make much difference.
Steve Rayner
officers hated them! It was too easy to forget to wind one, sometimes both.
The rule with two day chronometers was to wind them at the same time every
day. Back in the 1920s, the Empress of France was stuck off the coast of
Brazil, because the 8 day chronometers were not wound. No radio time signals
could be received there, so they had to sit tight until observations for a
"lunar" could be made.
--
Steve Rayner.
"boris beizer" <bbe...@sprintmail.com> wrote in message
news:cAh09.5220$XG5....@newsread1.prod.itd.earthlink.net...
Bob May
the clock couldn't get wound on one day.
Just because the clock could be run for a week, didn't mean that the
signalmen didn't wind more often.
--
Bob May
Global WARMING???
What I want to know is when I can start growing wheat in Greenland again!
Jack Erbes
<ud...@victoria.tc.ca> wrote:
>I wonder why the US Navy used 8 day chronometers? Most civilian deck
>officers hated them! It was too easy to forget to wind one, sometimes both.
>The rule with two day chronometers was to wind them at the same time every
>day. Back in the 1920s, the Empress of France was stuck off the coast of
>Brazil, because the 8 day chronometers were not wound. No radio time signals
>could be received there, so they had to sit tight until observations for a
>"lunar" could be made.
In the Navy they were normally wound every seventh day, the eight day
was a day of grace and to provide some spring power in reserve at
winding.
Jeffry Johnston
: Nah, it makes sense. His cheap binoculars were so far out of alignment
: anyway, that cutting them in half didn't make much difference.
Yep, you guess it, the first pair I separated was. They got mashed
between the truck seat and the door or something. I didn't do it, she
left, yippee. :) I tried to fix them and sorta could but the fix would
keep.
Compair a store bought monocular with a separated -pair- of 10x50's with
the green coating. G'head.
I'm not coordinated enough to look through binoculars with both eyes at
the same time anyway. :/
Alvin in AZ
Norman Yarvin
Jeffry Johnston <jef...@primenet.com> wrote:
>Compair a store bought monocular with a separated -pair- of 10x50's with
>the green coating. G'head.
Greenish coatings don't mean that much. They do mean that it's a
multicoat (since single coats should be purplish-blue, and generally
are), but good multicoats can be other colors, too. And a well-done
single coat can easily be better than a badly done multicoat.
(And, of course, if you just look at the outside, you're only seeing 2 of
the 8 (or more) surfaces that need coating. No, they don't always coat
the rest.)
>I'm not coordinated enough to look through binoculars with both eyes at
>the same time anyway. :/
Everybody has trouble looking through crummy binoculars with both eyes at
the same time! Try out a pair of good ones when you get a chance. (The
Bushnell/Bausch+Lomb "Custom Compact" recommended earlier on this thread
go for over $200, and most good ones sell for even more.) Matching the
two optical paths, in direction and magnification, is a lot harder than
just making two optical paths each of which is good on its own.
--
Norman Yarvin norman...@snet.net
boris beizer
news:3D42C459...@sympatico.ca...
> If it mounts on a wall, it's a clock not a chronometer.
Absolutely right! My face is red. And it say's right on there "ship's clock."
and not "chronometer." -- but then I've been known to call one of them 40,000
ton jobs a "boat."
Boris
> Chronometers were used <snip mini lesson on chronometer usage> This allowed
accurate estimation of longditude to be made.
>
> Does your clock chime the watches, or is it time only?
No ding-dong. If it does, I haven't found the lever or thingy that turns the
chimes on.
boris beizer
> On Sat, 27 Jul 2002 15:56:34 GMT, "boris beizer"
> <bbe...@sprintmail.com> wrote:
>
> This is the clock I was thinking of, in this case 1921 model made by
> Seth Thomas, they were supplied by other makers also (Chelsea was
> another).
>
> http://www.antiqnet.com/texis,rare_pre_wwii,3cc20ca20.html
Went there. Wow! $895 -- Not the same clock though. Mine has all the winders
and stuff in the back. But still must be worth something in the few hundred
dollar range.
> And at those prices your's might be worth the cost of an o-ring.
> Here is a source for a replacement key:
>
> http://www.frankenmuthclock.com/partsclock.htm
>
Thanks for the URL. They have the key. Key's cheap- $2.95. Shipping is $5.00.
More flea market time.
Mike Graham
> Absolutely right! My face is red. And it say's right on there "ship's clock."
> and not "chronometer." -- but then I've been known to call one of them 40,000
> ton jobs a "boat."
I thought a chronometer was just a particular kind of watch movement, and
anything with that kind of movement was a chronometer, whether it was hung
on the wall or not.
--
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Mike Graham | Fighting the good fight against porosity,
mi...@metalmangler.com | lack of fusion, and people who constantly
<http://www.metalmangler.com>| try to correct the spelling of 'weldor'.
boris beizer
news:slrnakb0r...@zippy.metalmangler.com...
> In article <TTc19.2720$w45.2...@newsread2.prod.itd.earthlink.net>, boris
beizer wrote:
>
> > Absolutely right! My face is red. And it say's right on there "ship's
clock."
> > and not "chronometer." -- but then I've been known to call one of them
40,000
> > ton jobs a "boat."
>
> I thought a chronometer was just a particular kind of watch movement, and
> anything with that kind of movement was a chronometer, whether it was hung
> on the wall or not.
Yes and no. The word "chronometer" is/has, often been (ab)used in the watch
trade to mean any fine watch movement with a stop-watch function. On ships,
"Chronometer" has a very specific meaning as a time-keeping device of sufficient
accuracy and stability to warrant its use in celestial navigation -- perhaps
most important of all, it has been certified for such use. A one second error
in time (can) puts you off by a quarter of a (nautical) mile. Shipboard
chronometers (at least the mechanical kind) were kept in gymballed boxes -- dem
cheap things on the wall are called "clocks" to distinguish them for the
expensive things in the boxes.
Now, of course, the point is moot. My $35 Casio Mariner is much better
than any WW2 mechanical chronometer -- and it is easiest to get excellent time
signals from a passing satellite.
I've learned a few important things about those "particular kind of
watch movements"
(1) they spend more time in the repair shop than out -- at least mine did.
(2) they cost as much as a good watch to clean and tune.
(3) The average age of the watchmaker who is competent to clean and repair
them is ten years more than the age of the watch.
I have a German one that's about 75 years old. Last time I had it
cleaned and repaired was 25 years ago, when it cost me (in the trade) $125. It
ran for about a year and gummed up again or something. I'll keep in the family
and someone will put their kids through college on it in a century or two.
Mike Graham
> Yes and no. The word "chronometer" is/has, often been (ab)used in the watch
> trade to mean any fine watch movement with a stop-watch function.
Ah, okay. I knew I remembered something about that. Now the original
ship's chronometers *were* a specific movement, weren't they? Like, you
couldn't rely on a pendulum in high seas, so somebody.. can't remember the
name of the guy, but he won a princely sum from some royal person or another
for inventing a clock movement that kept good time without the need of a
pendulum... so I recall, anyway. Now that I think about it, Rolex calls
their 'proper' watch movements chronometers.. if the hands don't move in
'ticks' then it's not a chronometer. Or something like that.
> I've learned a few important things about those "particular kind of
> watch movements"
> (1) they spend more time in the repair shop than out -- at least mine did.
> (2) they cost as much as a good watch to clean and tune.
> (3) The average age of the watchmaker who is competent to clean and repair
> them is ten years more than the age of the watch.
I guess back then they'd be cleaned and tuned after every voyage. Or
maybe there was someone aboard who knew how to keep it reasonable enough to
keep time until it could be cleaned properly.
Steve Strickland
"boris beizer" <bbe...@sprintmail.com> wrote:
>A one second error in time (can) puts you off by a quarter of a
(nautical) mile.
One of the senseless rainy day activities for a few telescope makers is to
take a really cheap digital watch and optically polish the crystal until
it matches the time ticks from the Naval Observatory. Incredible accuracy
has been achieved this way with a $3 watch.
--
Steve Strickland, Puzzlecraft
st...@puzzlecraft.com
www.puzzlecraft.com
boris beizer
> In article <8Vg19.3165$w45.3...@newsread2.prod.itd.earthlink.net>, boris
beizer wrote:
>
> > Yes and no. The word "chronometer" is/has, often been (ab)used in the watch
> > trade to mean any fine watch movement with a stop-watch function.
>
> Ah, okay. I knew I remembered something about that. Now the original
> ship's chronometers *were* a specific movement, weren't they? Like, you
> couldn't rely on a pendulum in high seas, so somebody.. can't remember the
> name of the guy, but he won a princely sum from some royal person or another
> for inventing a clock movement that kept good time without the need of a
> pendulum... so I recall, anyway.
Harrison. It was his #3 that finally won the prize for getting a reliable way
to find longitude at sea. There were many methods of doing that, but the
simplest (the one we essentially use today ) depended on having an accurate
time-piece. Point was that it could take you half a year to get to the other
side of the world, so if the chronometer was off by a second a day, you could be
50 miles off in your navigation -- not too cool when you can't see reefs at
night beyond a few miles.
Of significance to RCM is the fact that it was only the intervention of
George III that got Harrison his prize -- he had to fight long and hard to get
that payment. George III was "the royal person" in question. There is a fine
book on the subject "Longitude" and an excellent PBS mini-series of the same
name about Harrison and his chronometer. What both the book and the series
failed to mention, not even in passing, was that George III was a world-class
clock maker in his own right. Back then all aristocrats had to have an
"occupation." Peter the Great was a shoemaker and shipwright, George III was a
clock maker. As such, he was no mean home-machinist and had a deep appreciation
of what Harrison had created. As a further piece of incidental intelligence,
Holtzapffel, the author of the 5 volume set on the lathe and originator of many
features of the modern lathe, primarily catered to the "gentlemen machinists"
and their "occupation." = hobby.
Today, we have no royals (at least not in the US) the closes we have are
our senators, congressmen, judges, and executives -- perhaps we should make it
mandatory that they too have a "trade" -- lawyering being expressedly excluded.
Think how much better our lawmaking and government would be if we had some
machinists, mechanics, programmers, nurses, fire-fighters, etc. as the
"occupation" of our legislators -- yeah, yeah, yeah, and gunsmiths.
> Now that I think about it, Rolex calls
> their 'proper' watch movements chronometers.. if the hands don't move in
> 'ticks' then it's not a chronometer. Or something like that.
That's Madison Avenue speak. Rolex is typical of the remnants of the high-end
mechanical watch business who make a point of trying to convert mediocre
performance and total obsolescence into some kind of yuppy virtue. Give me my
Cascio Mariner every time.
> I guess back then they'd be cleaned and tuned after every voyage.
I was talking about wrist-watches called "chronometers" and not legitimate
ship's chronometers. Not sure what the ritual was for ship's chronometers --
but I'm sure it was damned expensive. About 35 years ago, I asked the fellow
in Philadelphia who calibrated, tuned, and/or cleaned mechanical chronometers --
back then it was about $200 a pop -- assuming that nothing had to be done to it.
>Or maybe there was someone aboard who knew how to keep it reasonable
> enough to keep time until it could be cleaned properly.
Ritual there also. Only officers (petty or otherwise) allowed to touch the
thing. Opening the case or fiddling with the works for any reason -- except
disaster -- was probably a hanging offense. You wound it, and looked at it --
period.
Mike Graham
> Today, we have no royals (at least not in the US) the closes we have are
> our senators, congressmen, judges, and executives -- perhaps we should make it
> mandatory that they too have a "trade" -- lawyering being expressedly excluded.
Now *there's* an interesting idea. One would expect, though, that all of
them had some kind of trade (though it may well have *been* lawyering)
before they became congressment, judges, etc. Just look at Jesse Ventura...
8-)
> I was talking about wrist-watches called "chronometers" and not legitimate
> ship's chronometers.
Oh, okay. I suppose a ship's chronometer would be in a larger package and
less prone to being gummed up, so it might last 2 years without need of
cleaning.
Mike Graham
> One of the senseless rainy day activities for a few telescope makers is to
> take a really cheap digital watch and optically polish the crystal until
> it matches the time ticks from the Naval Observatory. Incredible accuracy
> has been achieved this way with a $3 watch.
I'm not sure I understand this. Doesn't the watch have to be accurate to
begin with? I mean, if it gains a second per hour, then all the polishing
in the world won't help it... or is this based on the idea that the watch
just has a wonky gear that causes the duration of some ticks to be longer
than other ticks, so while a minute is accurate it has some seconds that are
longer than others?
James Waldby
> ... Steve Strickland wrote:
>
> > One of the senseless rainy day activities for a few telescope makers is to
> > take a really cheap digital watch and optically polish the crystal until
> > it matches the time ticks from the Naval Observatory. Incredible accuracy
> > has been achieved this way with a $3 watch.
>
> I'm not sure I understand this. Doesn't the watch have to be accurate to
> begin with? I mean, if it gains a second per hour, then all the polishing
> in the world won't help it... or is this based on the idea that the watch
> just has a wonky gear that causes the duration of some ticks to be longer
> than other ticks, so while a minute is accurate it has some seconds that are
> longer than others?
A quartz crystal's oscillation frequency depends on its
geometry and thickness. Changing the thickness a few
parts per million will shift the frequency correspondingly.
Other than electrons and a few switches, the quartz crystal
is the only moving part in a typical LCD watch.
I hadn't heard of lapping tuning-fork-style crystals
like the ones used in LCD watches (see picture at
http://www.si.edu/lemelson/Quartz/technology/quartz.html )
but before etching came into common use during WWII,
lapping, via adapted drill presses, was the final
surface treatment production step for radio crystals, per
http://www.corningfrequency.com/history/vbottom.html
-jiw
Gunner
>ators, congressmen, judges, and executives -- perhaps we should make it
>mandatory that they too have a "trade" -- lawyering being expressedly excluded.
>Think how much better our lawmaking and government would be if we had some
>machinists, mechanics, programmers, nurses, fire-fighters, etc. as the
>"occupation" of our legislators -- yeah, yeah, yeah, and gunsmiths.
Be careful of what you wish for,...Josef Stalin was a machinist....
<G>
Gunner
"One of the bargains men make with one another in order
to maintain their sanity is to share an illusion that they
are safe even when the physical evidence in the world
around them does not seem to warrant that conclusion."
-- Kai T. Erickson, _Everything in Its Path_
Trevor Jones
> I thought a chronometer was just a particular kind of watch movement, and
> anything with that kind of movement was a chronometer, whether it was hung
> on the wall or not.
>
In the context of a ship's clock, a chronometer is an accurate clock
with a known, observed, and recorded rate, usually, if not always, set
on a ginballed mount to maintain the clock in a "face up" position. The
US Naval Observatories were set up to be able to observe the stars
passing to use as a time reference, as I am led to beleive.
In the context of a wristwatch, a chronometer is a watch that has been
submitted to an agency that tests it's ability to keep to proscribed
timkeeping limits under varying positions and temperatures. It is then a
"chronometer". This certification is quite common on the high end o the
mechanical watch trade.
Not to be confused with a chronograph, which is a separate function put
onto a watch to allow specific events to be timed. Lot's of variations
of chronographs, both in function and execution.
Cheers
Trevor Jones
The cheapest GPS you can buy will still provide you with more accurate
time.
PLAlbrecht
Was he Union?
Pete
Gary Coffman
>In article <steve-29070...@66.76.9.47>, Steve Strickland wrote:
>
>> One of the senseless rainy day activities for a few telescope makers is to
>> take a really cheap digital watch and optically polish the crystal until
>> it matches the time ticks from the Naval Observatory. Incredible accuracy
>> has been achieved this way with a $3 watch.
>
> I'm not sure I understand this. Doesn't the watch have to be accurate to
>begin with? I mean, if it gains a second per hour, then all the polishing
>in the world won't help it... or is this based on the idea that the watch
>just has a wonky gear that causes the duration of some ticks to be longer
>than other ticks, so while a minute is accurate it has some seconds that are
>longer than others?
In a *digital watch*, a quartz crystal is the frequency reference (duration is
the reciprocal of frequency). A quartz crystal's resonant frequency can be
altered by lapping since its resonant frequency is a function of the crystal's
geometry (primarily thickness, though other dimensions, and the "cut" of the
crystal, matter too).
You can only *raise* the resonant frequency by lapping, though, so if the
watch is already "fast", lapping will just make it faster. Thus you want to
start with a watch that runs a bit slow. (You can "plate" the crystal with
solder, or even graphite from a pencil, to lower its frequency. But the
resulting frequency won't be very stable.)
Gary
Steve Strickland
mi...@metalmangler.com wrote:
> In article <steve-29070...@66.76.9.47>, Steve Strickland wrote:
>
> > One of the senseless rainy day activities for a few telescope makers is to
> > take a really cheap digital watch and optically polish the crystal until
> > it matches the time ticks from the Naval Observatory. Incredible accuracy
> > has been achieved this way with a $3 watch.
>
> I'm not sure I understand this. Doesn't the watch have to be accurate to
> begin with? I mean, if it gains a second per hour, then all the polishing
> in the world won't help it... or is this based on the idea that the watch
> just has a wonky gear that causes the duration of some ticks to be longer
> than other ticks, so while a minute is accurate it has some seconds that are
> longer than others?
>
Here's a brief explanation of it from "A History of the Quartz Crystal
Industry" on the Corning website:
http://www.corningfrequency.com/history/vbottom.html
Blanks were lapped by hand on a rotating cast iron plate called a
"stooging wheel" using silicon carbide and water as a slurry. After a few
hours of work, the operator of a stooging wheel was usually contributing
blood to the slurry from his/her finger tips. Many strange and wonderful
devices were used to replace hand lapping. Louis Patla of DX Crystal Co.,
the first to produce crystal units in the Chicago area, recalls making a
lapping machine from an old bread dough mixer. But most of the early laps
were made from drill presses. A crank was inserted into the chuck and used
to drive a metal carrier between two flat, annular cast iron plates while
abrasive slurry was fed in through holes in the top plate. Metal carriers
were replaced by plastic ones when it was discovered that, if the two
metal plates were insulated from each other, the quartz plates would
announce their own frequencies in a radio receiver. Soon the Atlas Machine
Co. began producing drill press laps and the Atlas lap became the most
commonly used lapping machine in the industry. In 1938 the P. R. Hoffman
Co. was organized to produce machinery for the expanding industry. One of
its first products was the Hunt-Hoffman planetary lap which is still
widely used today without substantial modification.
Steve Rayner
there used to be a law that only a clock with a spring detent escapement
could be called a chronometer. The Swiss seem rate any reasonably accurate
watch as a chronometer. Though the standards are strict, it's still a
marketing ploy. A real marine chronometer is head and shoulders above those
watches. I used to service ships chronometers, and therefore have some
direct experience.
--
Steve Rayner.
"Mike Graham" <mi...@metalmangler.com> wrote in message
news:slrnakb0r...@zippy.metalmangler.com...
Jack Erbes
Strickland) wrote:
<snip>
>Here's a brief explanation of it from "A History of the Quartz Crystal
>Industry" on the Corning website:
>http://www.corningfrequency.com/history/vbottom.html
>
>
>Blanks were lapped by hand on a rotating cast iron plate...
When I was a Novice Ham some years ago, we fine tuned the crystals (it
was then mandatory for Novices to use crystal controlled transmitters)
we used to lap them on pieces of plate glass using various light
abrasives to make minute adjustments in the transmit frequency. If
you goofed and got it outside the Novice band then you couldn't use it
any more.
I liked that tooth powder that came in the tall can (Pepsodent?) and
the standard technique was to place the tips of two fingers on
adjacent corners of the crystal (which maybe 3/4" square?) and slide
it around on the glass with an abrasive slurry using a figure 8
motion while continuously moving the pattern around on the glass also.
Then you had to was it, put it back in its holder, and see what you
had produced.
Jack Erbes
wrote:
> I'm not sure I understand this. Doesn't the watch have to be accurate to
>begin with? I mean, if it gains a second per hour, then all the polishing
>in the world won't help it...
The frequency at which the crystal vibrates will change if you remove
some of its mass. That frequency is the input to the mechanics of
the watch so changing it is like changing is like changing a gear.
This was done a lot in amateur radio to fine tune the transmit
frequency on crystal controlled transmitters.
Mike Graham
> A quartz crystal's oscillation frequency depends on its
> geometry and thickness.
Geez. Okay. When you said they optically-polished the crystal I thought
you meant... the crystal... the glass covering the face of the watch.
Steve Strickland
<jac...@midmaine.com> wrote:
> I liked that tooth powder that came in the tall can (Pepsodent?) and
> the standard technique was to place the tips of two fingers on
> adjacent corners of the crystal (which maybe 3/4" square?) and slide
> it around on the glass with an abrasive slurry using a figure 8
> motion while continuously moving the pattern around on the glass also.
>
That sounds pretty good. If you're a telescope maker you'd grab the cerium
oxide instead and do the same thing to the crystal to fine tune it to the
WWV time ticks.
I guess the point of my original post was the incredible timekeeping
accuracy achievable with a very cheap digital watch these days. In either
Sky & Telescope or Telescope Making magazine someone wrote an article on
it where they were able to match time ticks to something like 1 second of
error in 90 days, or thereabouts. I'd have to look it up to be sure of the
exact error.
Dave Martindale
>One of the senseless rainy day activities for a few telescope makers is to
>take a really cheap digital watch and optically polish the crystal until
>it matches the time ticks from the Naval Observatory. Incredible accuracy
>has been achieved this way with a $3 watch.
This doesn't seem right to me. First, why polish the crystal when you
can adjust the frequency with the trimmer capacitor that's provided in
the watch? I've adjusted a couple of my watches this way, and so far
there has always been a trimmer.
Second, even if you get it to keep *perfect* time under some set of
circumstances, the crystal is still temperature sensitive, so you have
to regulate the temperature of the watch all the time for it to retain
its accuracy. One way of doing this is to wear the watch all the time,
with your wrist providing temperature control. But if you don't want to
wear that watch to bed every night, the temperature is still going to
be uncontrolled 8 hours a day and accuracy will suffer.
Good quartz oscillators deal with this by using temperature compensation
or active temperature stabilization. Watches have no provision for
this (at least not cheap ones).
Dave
Bob May
that temperature does change the oscillation frequency of a chunk of quartz
all over the place. The errors are in the 10^-10 and above but they are
still there.
At one time, I wanted to do a high accuracy source of 10MHz and ended up
with triple linear controlled ovens for the temp control (the entire
controller for the next stage inside the previous oven even!) and ended up
finding that I was measuring the error of the test equipment. Then went to
dealing with the error with WWV (the best available at that time) before
finally figuring out that the WWV standards were about as accurate as what I
did. I probably should have talked with some of the people at WWV about the
experiment but that was more than 35 years ago.
Norman Yarvin
Norman Yarvin <norman...@snet.net> wrote:
>Everybody has trouble looking through crummy binoculars with both eyes at
>the same time! Try out a pair of good ones when you get a chance. (The
>Bushnell/Bausch+Lomb "Custom Compact" recommended earlier on this thread
>go for over $200, and most good ones sell for even more.) Matching the
>two optical paths, in direction and magnification, is a lot harder than
>just making two optical paths each of which is good on its own.
P.S. This is not to imply that all the features of more expensive
binoculars are necessary or even important. Indeed, getting "roof prism"
binoculars (the ones that look like they have straight-through optical
paths), instead of "porro prism" (the usual kind, where each path is bent
a total of 360 degrees through two prisms), is a waste of money, unless
you really have to have the very smallest binoculars possible.
--
Norman Yarvin norman...@snet.net
Steve Strickland
<bob...@nethere.com> wrote:
> As a guy that has played with the crystal for timing purposes, I'll tell you
> that temperature does change the oscillation frequency of a chunk of quartz
> all over the place. The errors are in the 10^-10 and above but they are
> still there.
> At one time, I wanted to do a high accuracy source of 10MHz and ended up
> with triple linear controlled ovens for the temp control (the entire
> controller for the next stage inside the previous oven even!) and ended up
> finding that I was measuring the error of the test equipment. Then went to
> dealing with the error with WWV (the best available at that time) before
> finally figuring out that the WWV standards were about as accurate as what I
> did. I probably should have talked with some of the people at WWV about the
> experiment but that was more than 35 years ago.
>
This would be of interest to astronomers who rely on WWV timing. Why don't
you go ahead and write it up? Defining the error envelope is useful.
Now here's some binoculars:
http://www.foothill.net/~sayre/22-in.%20binocular.htm
Gary Coffman
>As a guy that has played with the crystal for timing purposes, I'll tell you
>that temperature does change the oscillation frequency of a chunk of quartz
>all over the place. The errors are in the 10^-10 and above but they are
>still there.
It's much worse than one part in 10 billion (that's a 1 Hz error at 10 GHz).
That's close to practical atomic clock numbers. Non-temperature compensated
crystal oscillators are lucky to achieve 1 part in 1 million (10^-6) over a 0 to 40 C
temperature range.
Carefully built ovenized oscillators do about 1 part in 100 million on a good day.
1 part in 10 million is closer to what you expect from ordinary ovenized oscillators
used in such things as a Mitrek or Mastr II (commercial crystal controlled UHF
two way radios).
>At one time, I wanted to do a high accuracy source of 10MHz and ended up
>with triple linear controlled ovens for the temp control (the entire
>controller for the next stage inside the previous oven even!) and ended up
>finding that I was measuring the error of the test equipment. Then went to
>dealing with the error with WWV (the best available at that time) before
>finally figuring out that the WWV standards were about as accurate as what I
>did. I probably should have talked with some of the people at WWV about the
>experiment but that was more than 35 years ago.
HF WWV reception gives an accuracy of about 1 part in 10 million. That's
due to changing path lengths for ionospherically propagated signals. (The
transmitters are atomically referenced, but unless you're line of sight with
them, you can't get that accuracy at the reception point.) WWVL (60 kHz)
does better, about 1 part in 100 million, thanks to the more stable groundwave
propagation at that frequency.
GPS receivers are capable of achieving an accuracy of about 1 part in a billion.
The satellites carry atomic clocks, and doppler drops out as part of the position
calculation, so the only significant error left is line of sight propagation error through
the varying density atmosphere (speed of light varies with the permeability and
permitivity of the medium). The military version of GPS deals with that by using
two different frequencies (propagation errors are different in a known way for
different frequencies, allowing the propagation induced errors to be nulled in
the receiver).
The primary standards used by NIST are between 10 and 100 times better
than this (in other words, a 1 Hz error at 100 GHz). But you'd have to be right
there at the clock location to take advantage of it. Even a moderate run of
coax would throw things off, due to the production tolerances of the cable,
and environmental variables changing the electrical characteristics of the
cable, varying its propagation velocity (cable isn't nearly as stable as quartz).
Note, the atomic transition used in atomic clocks is absolute, by definition,
but in practice a lot depends on how you're able to extract and use that
transition. That's why even NIST's atomic clocks don't have zero error.
Gary
Bob May
had severa other sources of frequency reference that I was using and they
were all wandering about in almost random directions, it seemed. Some of
them were more sensitive to the ship's motion (as determined by rate changes
when underway) than some of the others. I also took into consideration the
approximate delay in time when away from the home port for the WWV time. It
was a bunch of fun for the group of us on the ship that were playing with
this.
DoN. Nichols
Steve Strickland <st...@puzzlecraft.com> wrote:
[ ... ]
>I guess the point of my original post was the incredible timekeeping
>accuracy achievable with a very cheap digital watch these days. In either
>Sky & Telescope or Telescope Making magazine someone wrote an article on
>it where they were able to match time ticks to something like 1 second of
>error in 90 days, or thereabouts. I'd have to look it up to be sure of the
>exact error.
One thing that I wonder about this enterprise is how sensitive
to thermal changes the resulting crystals were. I thought that the
tuning-fork crystals were rather poor on that characteristic, and the
watches depended on the body temperature of the wearer's wrist for some
stabilization.
Enjoy,
DoN.
--
Email: <dnic...@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 ---
DoN. Nichols
Norman Yarvin <norman...@snet.net> wrote:
[ ... ]
>P.S. This is not to imply that all the features of more expensive
>binoculars are necessary or even important. Indeed, getting "roof prism"
>binoculars (the ones that look like they have straight-through optical
>paths), instead of "porro prism" (the usual kind, where each path is bent
>a total of 360 degrees through two prisms), is a waste of money, unless
>you really have to have the very smallest binoculars possible.
And in the process, you lose some of the enhanced depth
perception you get from the wider spacing of the objective lenses.
Randal O'Brian
Seiko analog quartz watch. The crystal can is .054" in dia. and is .194"
long. I don't know how much smaller the crystal itself is, but I can see
that it would it would be iffy to alter it with required precision.
Randy
"Steve Strickland" <st...@puzzlecraft.com> wrote in message
news:steve-29070...@66.76.9.47...
Eastburn
1,000 cycles per second - xtal. The one has 5 (IIRC) zero's after it -
but then one or two were needed at the time.
Some day, I'll build a audio tone generator with it.
I"m in the process of building a board with 660 MHz, 1.3 GHz, 3.2 GHz
VCO/VXCO
(voltage controlled osc or xtal controlled osc) to test waveforms
through
my devices. Fun task.
Martin
--
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder
Martin Eastburn, Barbara Eastburn
@ home on our computer old...@pacbell.net
Jeffry Johnston
They didn't have any at wallyworld at the time anyway. :)
I found some pretty good ones for <$90, made in china, that RedField
thought was good enough to put their name and logo on. 10x50 big
clunky binoculars that no... don't have coated internal prisms.
So... the green coating isn't a different chemical than the older blue
coating? Just a different thickness?
Anyway, the new green coated scopes are better than the blue coated
scopes by the same manufacturer, in my experience.
The trick I was first shown on a green lensed scope was... "look at the
bottom of the windmill gear head... what do you see? ...with this scope
...now this scope"
Blue lensed scope = nothing but darkness
Green lenses = could see the grease and dirt hanging from the bottom of
gear head.
Norman Yarvin <norman...@snet.net> writes:
: >Everybody has trouble looking through crummy binoculars with both eyes
: >at the same time! Try out a pair of good ones when you get a chance.
: >(The Bushnell/Bausch+Lomb "Custom Compact" recommended earlier on this
: >thread go for over $200, and most good ones sell for even more.)
: >Matching the two optical paths, in direction and magnification, is a
: >lot harder than just making two optical paths each of which is good on
: >its own.
: P.S. This is not to imply that all the features of more expensive
: binoculars are necessary or even important. Indeed, getting "roof
: prism" binoculars (the ones that look like they have straight-through
: optical paths), instead of "porro prism" (the usual kind, where each
: path is bent a total of 360 degrees through two prisms), is a waste of
: money, unless you really have to have the very smallest binoculars
: possible.
: Norman Yarvin
No matter... this thread is now about watches, clocks and chrono-graphers
(old dance instructors) and the World Westling Vederation. ;)
Alvin in AZ