TJ:
In the world of ophthalmic lens labs, 0.12 is usually called a twelfth. Drove me out of my head for years, and you should see the dazed looks I get when I call it an eighth. FWIW, 3937 instantly converted to "EYES" in my brain. (Look at a phone keypad)
And even though we call my son TJ too, I'm sorry to say that 25.4 is firmly stuck here along with 28.317 L/ft3 and 16.39×10-3 L/in3.
In the world of ophthalmic lens labs, 0.12 is usually called a twelfth. Drove me out of my head for years, and you should see the dazed looks I get when I call it an eighth. FWIW, 3937 instantly converted to "EYES" in my brain. (Look at a phone keypad)
And even though we call my son TJ too, I'm sorry to say that 25.4 is firmly stuck here along with 28.317 L/ft3 and 16.39×10-3 L/in3.
Maybe it also makes a difference of where you're at. I'm living in a metric world so for me the inch is the odd one out at 25.4mm.
If you are living in an imperial world the mm is probably the odd one out and you get 1/25.4 or that 0.03937 stuff.
In laying out PCBs I work with 40mills being 1mm for hole diameters.
Jan
If you are living in an imperial world the mm is probably the odd one out and you get 1/25.4 or that 0.03937 stuff.
In laying out PCBs I work with 40mills being 1mm for hole diameters.
Jan
I'm still trying to get my brain around how 0.03937 can be more accurate and easier to remember than 25.4, when to my simple brain it appears to be the opposite on both counts. I am also struggling to think why this is worthy of a thread on DIYaudio.
Shall we now turn to F to C temperature conversion? Or somebody's gallon to someone else's gallon? Tons vs. tonnes?
Shall we now turn to F to C temperature conversion? Or somebody's gallon to someone else's gallon? Tons vs. tonnes?
Actually there are EXACTLY 25.4 millimeters to an inch, and the millimeter being 0.03937 of an inch is an approximation. People think of a meter as being 39.37 inches.
You made a good case for getting rid of the routine use of Imperial and US customary units.
Political posts and collateral removed.
Here a "mil" is .001", and is quite often used for the thickness of poly sheet. I've worked with machinists, and as a machinist for over 25 years, and never heard anyone use the term "mil" for anything other than a milling machine.
jeff
That's my point- machinists don't usually use the term "mils" except when they are referring to a mill- as in "milling" machine.
That is the way i have always done it and a lot easier to remember than the decimal fraction. A decent approximation is 2.5.
Up here in Canada most tape measures have both inches & mm althou you often see inches only on sale because they have cheap ones from the US.
dave
For what its worth...
I don't remember hearing the term mil very often and it was quite a while ago. (also was in USA) Don't remember one instance of anything using it and hey, maybe I'm wrong too. (could happen
) Didn't use tenths a lot either, for that matter, unless you were referring to the last digit of most displays. (.0001-.0009) That was the best most machine controllers could resolve to back then and even then there weren't many machines that could actually hold a tolerance better than a thou or so anyways. The only exception I can recall was an XYZ table used in line width measurements of IC wafers. That was fascinating. They used a video camera on a microscope and somehow used a proprietary algorithm to find the edges and used fractions of pixels to accurately measure in fractions of microns. Probably no big deal these days.
I digress...
Most everything to the right of the decimal was referred to as thousandths ie: 10 thou or 100 thou, etc.. When we (designers/builders) did a lot of conversions back n forth between metric and inch the longest length of travel was always under 10'. An old timer turned me on to that number and for some reason it stuck. I personally found it easier to use for general conversions of ball screw pitch, checking for correct movement, etc., etc. If absolute accuracy was needed (rare) it was converted using 25.4 or in encoder counts but general everyday use didn't require it. Only some European made machines used metric parts anyways.
I still use it to this day. What ever error is created is so small it just doesn't matter. Most calipers only have 3 or 4 digits to the right anyways. I don't ever measure or convert anything big enough to warrant the worry.
What number does everyone use for pi? Do you worry about the error it creates by rounding it to 3 or 4 digits after the decimal?
Anyways, not trying to convince anyone to do it my way. We all have our idiosyncrasies. This is mine.
TJ
I don't remember hearing the term mil very often and it was quite a while ago. (also was in USA) Don't remember one instance of anything using it and hey, maybe I'm wrong too. (could happen
) Didn't use tenths a lot either, for that matter, unless you were referring to the last digit of most displays. (.0001-.0009) That was the best most machine controllers could resolve to back then and even then there weren't many machines that could actually hold a tolerance better than a thou or so anyways. The only exception I can recall was an XYZ table used in line width measurements of IC wafers. That was fascinating. They used a video camera on a microscope and somehow used a proprietary algorithm to find the edges and used fractions of pixels to accurately measure in fractions of microns. Probably no big deal these days.I digress...
Most everything to the right of the decimal was referred to as thousandths ie: 10 thou or 100 thou, etc.. When we (designers/builders) did a lot of conversions back n forth between metric and inch the longest length of travel was always under 10'. An old timer turned me on to that number and for some reason it stuck. I personally found it easier to use for general conversions of ball screw pitch, checking for correct movement, etc., etc. If absolute accuracy was needed (rare) it was converted using 25.4 or in encoder counts but general everyday use didn't require it. Only some European made machines used metric parts anyways.
I still use it to this day. What ever error is created is so small it just doesn't matter. Most calipers only have 3 or 4 digits to the right anyways. I don't ever measure or convert anything big enough to warrant the worry.
What number does everyone use for pi? Do you worry about the error it creates by rounding it to 3 or 4 digits after the decimal?
Anyways, not trying to convince anyone to do it my way. We all have our idiosyncrasies. This is mine.
TJ
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Do you guys in the USA measure stylii profiles in mil or μm?
e.g. 0.4 x 0.7 mil or 10 x 18 μm
Here in the UK I find it almost impossible to find a measure that isn't both metric and imperial. I WANT one with metric on both sides.
Galu-- as machinists, we measure in inches or thousandths of an inch.
TJ started out by saying that USA machinists will usually convert to millimeters by multiplying millimeters x 0.03937".
That's what my old crusty machining brain does. Common machinist tools can't measure any better than four digits, "0.0000"
Not saying either way is right or wrong- it's what we do.
For chemistry and physics, metric measurements are much easier to use.
To answer your question, I've never measured a stylus with any measuring tool.
TJ started out by saying that USA machinists will usually convert to millimeters by multiplying millimeters x 0.03937".
That's what my old crusty machining brain does. Common machinist tools can't measure any better than four digits, "0.0000"
Not saying either way is right or wrong- it's what we do.
For chemistry and physics, metric measurements are much easier to use.
To answer your question, I've never measured a stylus with any measuring tool.
Is it something like this you are after? It says 'Metric ONLY'. https://www.amazon.co.uk/METRIC-Moore-Wright-Engineers-Rules/dp/B00OY575H8
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