So can dial calipers. The outer ring of the dial thingie rotates to offset zero. Then just count rotations if the difference is big.
-- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
torsdag den 10. maj 2018 kl. 02.43.23 UTC+2 skrev John Larkin:
absolutely and that means the cheap no-names are fine
I use digital calipers from ebay. $6.00 ea, 50 microinch resolution. Plenty good enough for the stuff I do. I also have vernier calipers. They are good but take longer to read. Also a chance of misreading due to adjacent reference marks.
Digital is the way to go. You cannot misread the display. You can set the zero any place you want to sort parts by dimension. You can flip between inches and mm instantly. Vernier calipers cannot do that.
The only problem is the batteries don't last very long and are a pain to replace.
But they kill batteries. They're always dead when I pick the thing up.
torsdag den 10. maj 2018 kl. 03.10.34 UTC+2 skrev snipped-for-privacy@notreal.com:
that where the expensive ones have an advantage, they can last years
Cyclohexane wasn't synthesised until 1894. It doesn't seem to occur naturally, and the first people who thought that they had made it had actually made methyl cyclopentane.
Physical methods are nice, but structural chemistry pre-dates them by a good fifty years.
Kekule's famous paper on the structure of benzene was published in 1865. His real innovation was more or less inventing structural chemistry about 1858.
It was nice work, but not all that amazing. Archibald Scott Couper independently published much the same kind of proposal in 1858 as Kekule did.
Cursitor Doom's amazement reflects the fact that he doesn't actually know what was involved.
-- Bill Sloman, Sydney
Years? I had a Starret that would go a year, at best. Is Starret expensive enough?
Equally one could point out that the buckminsterfullerenes were sat in soot just waiting to be discovered. Benzene extraction of soot would have found them but they remained undiscovered until Kroto made some in
1985. It wasn't like there was a shortage of soot in the Victorian era.There were even clues in astronomy with the mysterious spectrum of dust.
Same for graphene - ever since the invention of Sellotape 1937 it was just waiting to be found by someone playing with graphite and tape.
We are in a golden era of observational and experimental science with various diagnostic techniques that can see individual atoms and image living systems without damaging them. Even the bits of the magnetic spectrum previously unexplored like terahertz imaging is now possible although military uses mean they are rather thin on the ground.
Highly efficient CCDs have totally revolutionised imaging and video.
But there hasn't been a major breakthrough in modern mathematics that transforms how physics is written down since tensor calculus. String theory was at one point thought to be a possibility it may still prove to be the case but we have to wait and see. Clifford Algerbras and spinors are another contender at least for some fields of study.
-- Regards, Martin Brown
torsdag den 10. maj 2018 kl. 04.34.34 UTC+2 skrev snipped-for-privacy@notreal.com:
a year is about what I've heard for a Starret with everyday use, Mitutoyo twice that
Verniers are hard to read unless you do it constantly to stay in practice. Dial calipers are easy to use and don't need batteries.
-- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
My vernier caliper's mostly identical to the one shown on Wikipedia. [1] Note the inch scale on top and the cm scale on the bottom. Just this morning my caliper was used to verify the 5/16" size of an SMA male hex nut. A slight change of eye-focus downward from the inch scale to the cm scale instantaneously revealed that 8mm is equivalent to
5/16". The caliper's used by me all of the time to size things. Although the vernier itself is seldom used.Note.
73,
-- Don Kuenz, KB7RPU
I'm Gen X and I'd be okay with adding cars and homes to that list. Unfortunately I wasn't born into a world where a decent new car didn't cost the better part of six months salary. Must have been nice. Even used cars aren't cheap anymore.
When I moved here, it sure was. Lots of smart slim feminine women and lots of gay or dorky guys. I wouldn't have minded being the only straight male in town. I soon learned that having more than one gf at a time is too confusing.
I'm off the market now, but I don't think things have changed.
SF is now almost exactly 50% female, but as noted many of the guys are gay or uber-geeky. There are also lots of Asian women who, for some reason, don't want to date Asian men.
-- John Larkin Highland Technology, Inc lunatic fringe electronics
You obviously need a better job. Neither of my cars cost more than
20% of my income, new. I have no interest in spending 50% of my annual income on a car.Given the price of used trucks, it made a lot more sense to buy new, the last two purchases ('01 and '13).
Want to meet a great woman at a club? Join a ski club or a hiking club or a gardening club.
Full disclosure: I met my wife in a gay bar.
-- John Larkin Highland Technology, Inc lunatic fringe electronics
In the early days when colour TV was hopelessly unreliable and forever needing tweaks and adjustments there were several UK businesses that made a fortune renting colour TVs (with a service contract included). eg
Prior to that there was a similar business renting radios called "Radio Rentals" that went on to be a huge rental business for TVs & videos.
It may depend on your definition of a "decent" car. You can get something with a wheel at each corner for not very much at all.
At the moment you have to fight off UK car dealers if you are in the habit of buying new - they are absolutely desperate for sales. The VW diesel pollution fiasco has pretty much sunk the market over here.
-- Regards, Martin Brown
This kind of thing pisses me off. The oft-repeated advice to single women in the popular media is to go "join a club" in order to meet eligible men. It's sly and disingenuous in my view. The situation has got so bad now that it's simply assumed if you join any kind of club you are trying to meet your next partner and you're viewed as rather *odd* if you rebuff such unwelcome advances.
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I also find the visual indication of relative thicknesses a dial caliper gives you is invaluable. I have got a digital vernier one but it eats batteries alive and is *invariably* dead if left for a while. They need to put an on/off switch on those damn things.
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a Mitutoyo used 2uA in standby 4uA when on, it'll last for year
ty
od
The batteries in the units I have die because it isn't very off most of the time. I recall a web page where a guy measured the current on and off and off wasn't much lower than on, over 100 uA I want to say. A unit that was more quality got the idle current below 10 uA with the batteries lasting m uch longer.
You'd think someone in China would develop a chip that solves this problem sooner or later, but I guess as long as people keep buying the cheap ones, they won't bother with fixing them. Things like this are hard to influence unless the masses are behind it. A similar issue is with the indoor/outdo or thermometer/hydrometers. They pretty much all suck, but people keep buy ing them, so they don't bother to improve them.
Rick C.
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