Repair filter threads on lens?

"Winfried Buechsenschuetz" wrote in message
m...
"William Graham" wrote in message
news:0teXb.174834$U%5.821111@attbi_s03...
--
The reason for this is that large metal working machines like lathes and
milling machines are very expensive, and they last virtually
forever....So
if they are calibrated in inches, the operators just have to live with
that.
At the lab where I worked, the machine shop took pride in their ability
to
turn out items regardless of the dimension system used in the
specifications.

I am not sure about that. Most, if not all, machines can be equipped
with electronic measuring systems, we have some 20+ years old milling
machines with such equipment, and you just press a button to switch
from inches to mm. There are some companies specialised in equipping
old machines with modern measuring systems and sometimes they can even
convert them to automatic operation by adding motor drives where you
once had to turn manually.

It may be different for cutting threads. In these cases, the pitch of
the spindle and/or the number of teeth on some gears are important,
and they can't be changed easily. However, with most lathes
manufactured in Germany it is no big problem to convert them to
cutting inch-dimension threads.

Threads for tubing (water, gas and air tubes and their fittings) are
still in inch dimensions even in Germany, and I have severe doubts
whether this will ever change.

Winfried
This might well be true....My experience comes from the 70's and 80's....Our
machines had the calibration marks etched directly into the steel frames of
the machines. If you ordered new machines, you could specify metric marks,
but many of the old machines dated from the 50's or earlier, and they were
calibrated in inches. I can imagine that modern electronics could be used to
recalibrate these old beasts, in which case one wouldn't use the marks
etched into the machine frames at all, but simply read the electronic
displays from a chassis attached to the machine somewhere, but, as I say,
that would be after my time.......

In article , Winfried
Buechsenschuetz writes
"William Graham" wrote in message
news:0teXb.174834$U%5.821111@attbi_s03...

Blank Space.

That's what I got when I clicked on the follow-up button to reply to
Winfried.

Winfried, all your post, including William's post you are replying to,
was below the sig line. This meant my newsreader automatically trimmed
it from the reply, which is difficult if I want to quote you. The sig
(signature) line, or sig separator, is a line with, at the left, two
long dashes separated by a space, and nothing else on the line. It tells
"proper" newsreader software that all that is below is the senders
signature and can be cut off the reply. (It also comes in bright blue on
my newsreader, which makes it annoying to read.)

I don't know what newsreader you are using - OE is the most common
source of such deviations from agreed standards. Do you think you could
do us all a favour and change the defaults on your newsreader to avoid
this - I'm sure I'm not the only one who finds it annoying.

These standards have been used happily for years; typical of microsoft
to drive a coach and horses through them.
--
David Littlewood

When I took college chemistry on the 50's chemical reactions were measured
in centigrade, grams, etc...
When I worked in automobile manufacturing until 73, all engineering was done
in decimal inches, poundsfeet, etc..
Funny thing, that 'USA dark ages', stuff got us thermonuclear devices, men
on the moon, solid state electronics, the computer, etc... Now, the rest of
the world sneers and looks down their long noses, but they are the ones who
are provincial because of their inability to work in other units...
I work handily in either millimeters or decimal inches.. I can read a ship
lofting of 3-4-8 ( 3 foot + 4 inches + 3/8ths inches)... I reload
ammunition using grains.... I write medications using milligrams and
drams... I have zero problems understanding old surveys that are calculated
in chains or rods... When I read of a land sale in hectares I don't throw
the paper down in disgust... I know how much oil is in a barrel and whats
the difference in a long tonne and a short tonne... I can understand a sale
of wheat reported in bushels.. I understand the race results at Churchill
downs at five furlongs not meters for gawds sake! The world was
circumnavigated by the english captains in nautical miles, not kilometers...
I fly using knots without giving it a second thought, why would I need to
use kilometers?
The Romans built engineering wonders of their time without using metrics...
The egyptians built the pyramids without ever hearing of SI, or meters...
The units of measurement do not make or break the product...
It's time for decadent europe to catch up with those of us who are not
handicapped by being only capable of metrics..
denny

I agree the USA is still mostly in the dark ages. The chemical
engineers
there still use the Fahrenheit/Rankine temperature scale, for goodness
sake!

In article , Winfried
Buechsenschuetz writes
"William Graham" wrote in message
news:0teXb.174834$U%5.821111@attbi_s03...

[Sorry if the quotation designators are all screwed up below - for the
reasons I set out in another post, I had to paste them back in by hand.]

The reason for this is that large metal working machines like lathes
and
milling machines are very expensive, and they last virtually
forever....So
if they are calibrated in inches, the operators just have to live
with that.
At the lab where I worked, the machine shop took pride in their
ability to
turn out items regardless of the dimension system used in the
specifications.

I am not sure about that. Most, if not all, machines can be equipped
with electronic measuring systems, we have some 20+ years old milling
machines with such equipment, and you just press a button to switch
from inches to mm. There are some companies specialised in equipping
old machines with modern measuring systems and sometimes they can even
convert them to automatic operation by adding motor drives where you
once had to turn manually.

This is true even of machines used in amateur workshops like mine. The
equipment for cutting to precise length or diameter in metric or
imperial is quite cheap, and switching between the two takes a couple of
seconds.

It may be different for cutting threads. In these cases, the pitch of
the spindle and/or the number of teeth on some gears are important,
and they can't be changed easily. However, with most lathes
manufactured in Germany it is no big problem to convert them to
cutting inch-dimension threads.

This is, as you say, the big problem. It takes me at least 15 min to
change my screwcutting gearbox from imperial to metric or back. This
makes cutting metric threads an utter pain. For small diameters it's
easy enough to diecut them but this is not possible for threads like
camera filter threads.

Threads for tubing (water, gas and air tubes and their fittings) are
still in inch dimensions even in Germany, and I have severe doubts
whether this will ever change.

That's interesting!
--
David Littlewood

In article
, Bob
Salomon writes
In article ,
David Littlewood wrote:

I believe camera lens filter threads are all 0.75mm pitch;

No. Depending on the size filters lenses have 0.5, 0.75, 1.0 and 1.5
pitch threads.

Heliopan has brass mounts on their filters up to 135mm diameter and many
sizes may have more then one pitch size. That is where the E and ES
designation on German filters comes from. One is for fine and the other
stands for coarse pitch threads.

OK, it's a fair cop!

I guess I should have said "no, the thread pitch does not automatically
drop from 0.75mm to 0.5mm below 40mm diameter as someone suggested;
*most* normal, modern 35mm and digital cameras still have 0.75mm thread
pitch at least down to 27mm, though there may be exceptions."

There, does anyone disagree?
--
David Littlewood

"Winfried Buechsenschuetz" wrote in message
m...
[SNIP]
Threads for tubing (water, gas and air tubes and their fittings) are
still in inch dimensions even in Germany, and I have severe doubts
whether this will ever change.


Im always amused by the size designations of Quickfit (R) laboratory
glass-ware. The joints are designated by their size in millimetres,
diameter (at the large end) followed by length. They're all very odd
combinations of numbers that seem to have been chosen randomly - until you
convert the millimetres and find that basically they're all multiples of
1/16 inch...



Peter

On Sat, 14 Feb 2004 07:41:04 -0500, "Dennis O'Connor"
wrote:
It's time for decadent europe to catch up with those of us who are not
handicapped by being only capable of metrics..
denny

ONE WORLD, ONE RULER......AND HIS NAME WILL BE INCHES.
Corinth-inch-ians 2.13.1

Michael.....

On Sat, 14 Feb 2004 07:41:04 -0500, "Dennis O'Connor"
wrote:
... Now, the rest of the world sneers and looks down their long noses, but they are the ones who
are provincial because of their inability to work in other units...

Does anyone remember this little story;

Metric mishap caused loss of NASA orbiter

September 30, 1999
Web posted at: 4:21 p.m. EDT (2021 GMT)

Metric system used by NASA for many years
Error points to nation's conversion lag
By Robin Lloyd
CNN Interactive Senior Writer

(CNN) -- NASA lost a $125 million Mars orbiter because a Lockheed
Martin engineering team used English units of measurement while the
agency's team used the more conventional metric system for a key
spacecraft operation, according to a review finding released Thursday.

http://www.cnn.com/TECH/space/9909/30/mars.metric.02/

In article , Dennis O'Connor
writes
When I took college chemistry on the 50's chemical reactions were measured
in centigrade, grams, etc...
When I worked in automobile manufacturing until 73, all engineering was done
in decimal inches, poundsfeet, etc..
Funny thing, that 'USA dark ages', stuff got us thermonuclear devices, men
on the moon, solid state electronics, the computer, etc... Now, the rest of
the world sneers and looks down their long noses, but they are the ones who
are provincial because of their inability to work in other units...
I work handily in either millimeters or decimal inches.. I can read a ship
lofting of 3-4-8 ( 3 foot + 4 inches + 3/8ths inches)... I reload
ammunition using grains.... I write medications using milligrams and
drams... I have zero problems understanding old surveys that are calculated
in chains or rods... When I read of a land sale in hectares I don't throw
the paper down in disgust... I know how much oil is in a barrel and whats
the difference in a long tonne and a short tonne... I can understand a sale
of wheat reported in bushels.. I understand the race results at Churchill
downs at five furlongs not meters for gawds sake! The world was
circumnavigated by the english captains in nautical miles, not kilometers...
I fly using knots without giving it a second thought, why would I need to
use kilometers?
The Romans built engineering wonders of their time without using metrics...
The egyptians built the pyramids without ever hearing of SI, or meters...
The units of measurement do not make or break the product...
It's time for decadent europe to catch up with those of us who are not
handicapped by being only capable of metrics..
denny

I agree the USA is still mostly in the dark ages. The chemical
engineers
there still use the Fahrenheit/Rankine temperature scale, for goodness
sake!

Dennis, I think you are missing my point - my fault for being to
flippant I suppose. I do not intend to "look down my long nose" at the
USA; look at it more as pulling the leg of a friend with a mildly odd
habit.

I agree that anyone who can cope with more than one system of units is a
more versatile person than someone who cannot. I learned both systems at
school, and use them happily (or sometimes with mild frustration) in my
own workshop. For simple dimensional measurement work the two systems
are fairly equally easy to use.

Nevertheless, it is undoubtedly true that working in a system of units
different from the SI system virtually universal in almost all sciences
- even in the USA - makes US chemical engineering very difficult for
others - whether non-US workers, or US workers in other scientific
disciplines - and we have to struggle much more than is necessary.

There is no doubt that the SI system is much more rational and easier to
work with in complex scientific issues, and for an Englishman to say
that of a system with its roots in the legal reforms of Napoleon
Bonaparte must be praise indeed.

PS - Hate to start a "who invented what" match, but can't resist this:
the first working electronic computer was developed by British Post
Office engineers in WWII - predating the first US computer by several
years, and playing a material part in the winning of the war.
Unfortunately, because of the extreme secrecy of the work it was used
for, it was destroyed at the end of the war and got very little
publicity until decades later.

PPS - my nose is not particularly long.
--
David Littlewood

In article , "Dennis O'Connor"
wrote:

When I took college chemistry on the 50's chemical reactions were measured
in centigrade, grams, etc... [...]

Fifties! You have my admiration. Chemistry is so much more complicated
now. When I was in school, we had only three elements: earth, wind and
fire.