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Open the box your micrometer comes in. It will usually say measurements are in thousands of an inch and not mills. Engineers have corrupted this in the shop. However the Sodic CNC EDM machine I ran used milliradians for head angles. 17.777 mils = 1 degree.
Fun haw ?
The number of milliradians in a degree is 1000 x 2 x pi / 360, which my calculators all reckon is 17.453.
Perhaps pi has a different value in the Southern Hemisphere?
I do not worry much about what means what
. Whenever I measure anything in English measure I think of Henry the Eighth. The Inch reminds me of his thumb, the yard reminds me of his arm, and the foot, well I leave that to your imagination.
When I measure anything in Metric I think of Napoleon, 25 mm for his thumb, a meter for his arm, and centimetres, well again I leave them to your imagination.
Regards David Powell.
I do not worry much about what means what
. Whenever I measure anything in English measure I think of Henry the Eighth. The Inch reminds me of his thumb, the yard reminds me of his arm, and the foot, well I leave that to your imagination.
When I measure anything in Metric I think of Napoleon, 25 mm for his thumb, a meter for his arm, and centimetres, well again I leave them to your imagination.
Regards David Powell.
ROFL thank you for that. When I use the Imperial system, it makes me think of how the origins of measures evolved --
Ancient Egypt and Babylon for example. Their "foot" was 30 CM just like ours but they divided everything else into parts of the body, in the same way that equestrians measure horses in terms of "hands" and "digits".
And units of volume and weight were based on the usual volume and weight of rations when agriculture first began. In some cases those measures continue to this day.
Open the box your micrometer comes in. It will usually say measurements are in thousands of an inch and not mills. Engineers have corrupted this in the shop. However the Sodic CNC EDM machine I ran used milliradians for head angles. 17.777 mils = 1 degree.
Fun haw ?
I'm betting it will say measurements are in thousandTHs of an inch.
ROFL thank you for that. When I use the Imperial system, it makes me think of how the origins of measures evolved --
Ancient Egypt and Babylon for example. Their "foot" was 30 CM just like ours but they divided everything else into parts of the body, in the same way that equestrians measure horses in terms of "hands" and "digits".
And units of volume and weight were based on the usual volume and weight of rations when agriculture first began. In some cases those measures continue to this day.
When I was in England, I put a €10 pound note on a scale. It was a LOT less than 10 lbs. History and the effect it has today is fascinating. We Americans, would have been better off with the metric system. I convert all fractions to decimals so its base 10. A case can be made for metric threads. 10mm x.1
tap drill is. 10mm - .1mm = 9.9mm tap drill. Sooo easy compared to a 9/16- 18. Tap drill calculation.
When I was in England, I put a €10 pound note on a scale. It was a LOT less than 10 lbs. History and the effect it has today is fascinating. We Americans, would have been better off with the metric system. I convert all fractions to decimals so its base 10. A case can be made for metric threads. 10mm x.1
tap drill is. 10mm - .1mm = 9.9mm tap drill. Sooo easy compared to a 9/16- 18. Tap drill calculation.
To make it more fun I wrote ,- ( .1 ) not 1. Yes my eyes miss alot too. Hell to get old. You guys are tough on me this week. First it was milliradians and now my math. LOL.....Thanks !! I am very impressed with the folks on this forum, but dont screw up or ur toast !
So, what about a "lakh" of something? Or a "crore"?
And you complain about kilo, milli, etc.
CNC machines only go through the motions.
Ideas expressed may be mine, or from anyone else in the universe.
Not responsible for clerical errors. Or those made by lay people either.
Number formats and units may be chosen at random depending on what day it is.
I reserve the right to use a number system with any integer base without prior notice.
Generalizations are understood to be "often" true, but not true in every case.
In today's world, with many micrometers being made in countries where English is not the primary language and translation is necessary, you may lose that bet.
It is actually the EXACT same calculation (Nominal OD - Thread Pitch) with the thread pitch expressed in the same units as the diameter (you simply take the reciprocal of the thread pitch in TPI or in this case, 1/18). I have at least three calculators that do fractions but it can be done on any four banger without even using the memory.
9/16" - 1/18" = 0.5069"
Nothing hard about that. OK, it took me 10 keystrokes. Big deal. The harder part is finding an actual drill bit of a size that will work, but that is or at least should be easy too:
0.5069" X 64 = 32.44 64ths of an inch. And that means that you should select either a 1/2" (32/64") or a 33/64" drill bit unless you just happen to have one that is closer. But the letter and number sizes of drill bits stop at 1/2" so few shops will have anything other than 64th inch sizes of bits larger than 1/2" and that are actually in stock. 12.9mm would be a better size (0.5079"), but who has one of them right now? About as many as there are shops in metric countries with a 9.9mm drill bit. In case you haven't noticed, an M10-0.1 thread is not very standard so there would be little reason for a metric shop to have a 9.9mm bit ready and raring to go.
Personally, I have an Excel spreadsheet that I use for the tap drill calculation for odd-ball thread sizes. It not only handles both English and Metric threads, but also any angle Vee and any odd-ball percentage of the flat at the crest or the fill at the bottom. And it will both allow you to ask for any percentage of a full thread and allow you to easily find and know exactly what the percentage of a full thread you will wind up with when you select a standard diameter drill bit instead of the calculated one. In short, you can know exactly what you are doing.
As for your 10 pound note on a scale, I doubt that a US silver certificate (now no longer used) would have weighed exactly one ounce. SO WHAT?
Perhaps we would be better off if we used the metric system, but we and everyone else can work with any and all systems with just a little bit of effort. And perhaps we are better off here in the US where we can and do work with BOTH systems. (At least I certainly do.) It sharpens our minds. While driving, I was once asked by my wife how much the length of a bridge would be in km. After glancing at the sign which gave that number in miles I told her. Did the calculation in my head while keeping in my lane and following the speed limit and also observing a couple of bathing beauties on the near-by beach (but she didn't know that part). You just have to know how to work with what you are given.
When I was in England, I put a €10 pound note on a scale. It was a LOT less than 10 lbs. History and the effect it has today is fascinating. We Americans, would have been better off with the metric system. I convert all fractions to decimals so its base 10. A case can be made for metric threads. 10mm x.1
tap drill is. 10mm - .1mm = 9.9mm tap drill. Sooo easy compared to a 9/16- 18. Tap drill calculation.
Paul A.
SE Texas
And if you look REAL close at an analog signal,
You will find that it has discrete steps.
Agreed, and amen. I live within walking distance of the Canadian border,
so doing unit conversions and currency swap is second nature.
I don't agree that metric is superior to Imperial in any way.
I don't believe in inherent superiority.
Those who fanatically push metric as being somehow "superior" simply turn me off.
I did grow up using metric for electronic and scientific work, I have no issues with that.
It is a good system for that.
But every day commerce is usually Imperial, and that is my preferred system.
Having spent a fair amount of time studying the history of the system,
I do not see the inconsistencies that others complain of.
But you *do* have to know about the origins of the system (before 2,000 BC) for it to make any sense.
Sadly, this history is not taught in schools.
It is really the history of international trade, and the history of agriculture..
It is actually the EXACT same calculation (Nominal OD - Thread Pitch) with the thread pitch expressed in the same units as the diameter (you simply take the reciprocal of the thread pitch in TPI or in this case, 1/18). I have at least three calculators that do fractions but it can be done on any four banger without even using the memory.
9/16" - 1/18" = 0.5069"
Nothing hard about that. OK, it took me 10 keystrokes. Big deal. The harder part is finding an actual drill bit of a size that will work, but that is or at least should be easy too:
Perhaps we would be better off if we used the metric system, but we and everyone else can work with any and all systems with just a little bit of effort. And perhaps we are better off here in the US where we can and do work with BOTH systems. (At least I certainly do.) It sharpens our minds.You just have to know how to work with what you are given.
Paul- € 10 pounds = 10 lbs was a joke. You dont weigh 50 stones, or maybe? Just fascinating all the weights and measurements past and current around the world.
Watch out for your wobbly bits as the Brits would say.
I am still looking for that 10mm x .1 Tap.
Metric is superior but I like the absurdity of the imperial system. Well, actually, what I was brainwashed with first.
"Metric is superior"
I agree. I am of a certain age (56) to where I remember the attempt at the US to get with the rest of the World and go Metric.
Im fluent in both as much as the other numbering systems. Hahaa. I speak them all, from One or Not (binary) measuring all the way up.
I like true numbers. I like the metric system.
I can do .00001mm. Thats easy. That is the ten Thousandth place off the decimale point. In the negagtive direction. You might call it something else on the other side of the decimal point. Like 10 kilometers
When dealing with elecronics, the teram between watts and power I get confused. I dig that. milliwatt is the same as kwatt. Just different sides of the decimal point. So a Bevawatt is a billion and same as nano on the other side of the decimle?
Micro, like in Micro-meter, the tool we mostly use. Well I do have a tape measure too JR
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