I have no idea why I would need "optical flats". I know what a granite table is as we have several of them, like a 15 ton one. But am not understanding as to need there yet.
Sorry to mix units, but the leadscrew was metric...
DPH, I am looking to make clock/watch gears and parts. I could use the mill and/ or lathe as others do.... but EDM is just sooooo cool. I have a rotary stage, but would need a dividing head...not yet out of the question.
My research into EDM, they have not controlled loop size therefore inductance. I intend to run a stripline to the work/wire interface so that the current risetime is in the low nanosecond range. I am thinking that I can keep the voltage lower and increase the pulse rep rate so get a faster cut with a better surface finish.
Who knows..but, I will enjoy the trip.
Jn
Sorry to mix units, but the leadscrew was metric...
DPH, I am looking to make clock/watch gears and parts. I could use the mill and/ or lathe as others do.... but EDM is just sooooo cool. I have a rotary stage, but would need a dividing head...not yet out of the question.
My research into EDM, they have not controlled loop size therefore inductance. I intend to run a stripline to the work/wire interface so that the current risetime is in the low nanosecond range. I am thinking that I can keep the voltage lower and increase the pulse rep rate so get a faster cut with a better surface finish.
Who knows..but, I will enjoy the trip.
Jn
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Standard Toolmakers reference for square accuracy is a cylinder square (ground
on a cylindrical grinder) used on granite table. I made mine 40 years ago.
TCD
I am a retired a metrologist. I worked in testing and calibration laboratories for 30+ years including a long stint at the largest aerospace manufacturer in the U.S.A. I am still active in writing ASME standards, however.
Terry, aka a bottle square? I made 2 as an apprentice in the same era, one is still in existance
One of the satisfying uses of simple technology for precision
Anyone involved in metrology will be familiar with the Josephson Junction reference
Josephson voltage standard - Wikipedia
Josephson voltage standard - Wikipedia
This is a typical round reference.
TTC 12" Length, 4" Shaft Diameter Cylinder Square | 57-020-264 | Travers Tool Co., Inc.
Note it is a reference and not a standard. A plumb bob uses only gravity to set the angle. A level also uses gravity. To make a level surface a standard one needs a flat surface and liquid. You can test a flat surface with an optical flat.
The history of how precision is obtained is quite interesting.
These days monochromatic light sources can be used for rather good precision.
J,
Place the rod under test on a level flat surface near the reference diameter pin. Suspend an optical flat on them. Then use a level optical flat of a larger size suspended just above the other flat. If the two rods are the same diameter you will have a uniform interference pattern. You can rotate the pin under test to see if it is really round. A truly ridiculous but highly accurate comparison method.
Now how would you test to see if a tone is really 1,000 hertz?
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While that is more expensive than a bottle of centenaire, it is cheaper that a bottle of 1880.
It cannot be good that I gage everything against alcoholic beverages...
It is interesting watching the laser guys survey a one half mile diameter machine at the 10 micron range. The beam dynamics physicists apparently can tell what the phase of the moon is by the diameter of the machine. Also, seasonal changes, as well as tides and whether it is rush hour on the expressway 4 miles away.
Of course, that is all because some engineer responsible for designing the entire cable tray system as well as cable segregation, kept the timing fibers away from the wires that dissipate heat, the beam position monitor cables away from all electromagnetic broadcasters, and what else..he is just so handsome....and athletic (well, had to put that in despite reality).
hmmm., wonder who that could be???
jn
ps...Ed, I'm still trying to wrap my head around a sine bar.. granted, it's 7th grade math, but whoa..
It cannot be good that I gage everything against alcoholic beverages...
It is interesting watching the laser guys survey a one half mile diameter machine at the 10 micron range. The beam dynamics physicists apparently can tell what the phase of the moon is by the diameter of the machine. Also, seasonal changes, as well as tides and whether it is rush hour on the expressway 4 miles away.
Of course, that is all because some engineer responsible for designing the entire cable tray system as well as cable segregation, kept the timing fibers away from the wires that dissipate heat, the beam position monitor cables away from all electromagnetic broadcasters, and what else..he is just so handsome....and athletic (well, had to put that in despite reality).
hmmm., wonder who that could be???
jn
ps...Ed, I'm still trying to wrap my head around a sine bar.. granted, it's 7th grade math, but whoa..
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Story goes that Josephson went barking mad and started investigating metaphysics later in his career. You can't sack a nobel laureate so he was just left to try and levitate his desk with the power of his mind. The reality may be slighly less embellished
I did get a tour of a voltage calibration lab in the 80s when chosing a university. I have never seen so many digits on a volt meter before or since! First and last time I saw a standard cell as well. I am glad some will spend a good chunk of their careers coming up with more accurate ways of measuring fundamentals but I lack the stoicism to be one of them.
While that is more expensive than a bottle of centenaire, it is cheaper that a bottle of 1880.
It cannot be good that I gage everything against alcoholic beverages...
It is interesting watching the laser guys survey a one half mile diameter machine at the 10 micron range. The beam dynamics physicists apparently can tell what the phase of the moon is by the diameter of the machine. Also, seasonal changes, as well as tides and whether it is rush hour on the expressway 4 miles away.
Of course, that is all because some engineer responsible for designing the entire cable tray system as well as cable segregation, kept the timing fibers away from the wires that dissipate heat, the beam position monitor cables away from all electromagnetic broadcasters, and what else..he is just so handsome....and athletic (well, had to put that in despite reality).
hmmm., wonder who that could be???
jn
ps...Ed, I'm still trying to wrap my head around a sine bar.. granted, it's 7th grade math, but whoa..
Methinks your vocation has given you expectations unattainable in your avocation. I am very glad here when I hold tolerances to +/- 0.5 mil. on my 25 year old knee mill and machine lathe. It is like Ed says: after the roughing and getting within a mil or so, let it rest overnight...
I used to work with machinists who could set up a compound sine table in minutes while my brain squirmed in it's pan watching them...one sine bar, sure...
Have fun!
Howie
Story goes that Josephson went barking mad and started investigating metaphysics later in his career. You can't sack a nobel laureate so he was just left to try and levitate his desk with the power of his mind. The reality may be slighly less embellished
There have been more, Shockley for instance.
It is trivial to attain motion resolution at the one nanometer level now, it is COTS.
Less than 1k dollars..invar scale, optical head..absolutely amazing.
I want to learn how to machine at the quarter mil level, 6 micron metric.
As I face plant on that learning curve, I learn how to even speak to the mech designers...understanding what your co-workers do is very important if you are in charge of a "skunkworks" type of group.
Jn
Actually, I was hoping for affirmation on the athletic and handsome thing...sigh, no joy
Less than 1k dollars..invar scale, optical head..absolutely amazing.
I want to learn how to machine at the quarter mil level, 6 micron metric.
As I face plant on that learning curve, I learn how to even speak to the mech designers...understanding what your co-workers do is very important if you are in charge of a "skunkworks" type of group.
Jn
Actually, I was hoping for affirmation on the athletic and handsome thing...sigh, no joy
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Story goes that Josephson went barking mad and started investigating metaphysics later in his career. You can't sack a nobel laureate so he was just left to try and levitate his desk with the power of his mind. The reality may be slighly less embellished
Brian Josephson is still very much alive, aged 81. But he started getting interested in odd things to do with higher states of mind in about 1970, when he was only 30. So it is nothing to do with later in life weirdness.
Let's not forget that Newton, after his two massive works Principia and Optiks spent much of the rest of his long life studying alchemy and trying to transmute metals.
Strange guy all round. As a professor at Cambridge University, he was required to give lectures. But he was so deeply disliked by the students that they never went. So Newton gave the lectures to an empty lecture hall.
Craig
https://www.edn.com/go-inside-flukes-electrical-metrology-lab/
In esoteric books, Isaak Newton has been treated as one of (or The One) Great Masters of his times
Chymistry of Isaac Newton: Browse
George