Why did machinists EVER start using degrees minutes an seconds?

edwin dirnbeck · Nov 11, 2017

I started the working in the trade in the 1955. There were no calculaters, and all angles were figured using Trig tables with error inducing degrees minutes and seconds.Why would anyone start doing this ? If you were trying to estimate a potion of a degree, such as 43 minutes,How would you ever estimate 43 parts of 60?Also why would any modern day designer use anything but decimal degrees? Edwin Dirnbeck

Myrmidon · Nov 11, 2017

Angular measurements were measured that way for quite some time before machinists ever came around.

So they adopted the existing practices.

Ziggy2 · Nov 11, 2017

edwin dirnbeck said:
I started the working in the trade in the 1955. There were no calculaters, and all angles were figured using Trig tables with error inducing degrees minutes and seconds.Why would anyone start doing this ? If you were trying to estimate a potion of a degree, such as 43 minutes,How would you ever estimate 43 parts of 60?Also why would any modern day designer use anything but decimal degrees? Edwin Dirnbeck

You can thank the Babylonians and the Persians that used a base 60 number system. It is also related to the annual calendar being that they were astronomers.

Old conventions die hard and this is a very good example. About 3000 yrs. worth.

Bill D · Nov 11, 2017

tradition. Same reason they do not use grads or mills today. mills would probably make more sense then degrees.
I asked and was told the US military today uses mills not degrees for the most part. They also use Kilometers not miles.
Bill D

Forrest Addy · Nov 11, 2017

Blame your grandpas back to the Phoenicians. They're the folks who counted by 12's and 60's and who regarded 360 as a mystical number.

billzweig · Nov 11, 2017

In scientific, as well as many engineering applications, radians are used for angular measurements.

Jashley73 · Nov 11, 2017

Bill D said:
tradition. Same reason they do not use grads or mills today. mills would probably make more sense then degrees.
I asked and was told the US military today uses mills not degrees for the most part. They also use Kilometers not miles.
Bill D

Serious question. What are "mills" in this context?

I always thought that using "gradients" for geometry/trig would have made a lot of sense...

Ziggy2 · Nov 11, 2017

Jashley73 said:
Serious question. What are "mills" in this context?

I always thought that using "gradients" for geometry/trig would have made a lot of sense...

1 mill=.001 of a radian. 2pi radians =360deg.

It is primarily used by the military since it makes angular and distance measurement very straight forward mathematically.

MattiJ · Nov 11, 2017

Jashley73 said:
Serious question. What are "mills" in this context?

I always thought that using "gradients" for geometry/trig would have made a lot of sense...

Milliradian - Wikipedia

Yan Wo · Nov 11, 2017

Jashley73 said:
Serious question. What are "mills" in this context? ...

"Mil" is short for milliradian, or one thousandth of a radian. A radian is the angle measured from the center of a circle to the ends of its radius superimposed on its circumference. That works out to (180 / pi) degrees, or about 57.3 degrees.

Matt Matt · Nov 11, 2017

I believe it was the Persians that made a triangle equilateral. Six of them created a circle. They considered the equal lateral triangle the strongest Point load shape on earth. There is something about 2000 years ago they only thought there was 360 days in a calendar year. So an orbit should equal 360°. Back then pretty good math. But as the circle works, it’s really good math. Then came along the linear scale. Cut a circle 360 times/Degrees then make 60 minutes using the triangle theory, then cut each triangle into 60 minutes. It’s pretty good for most angles. But when you’re given a angle of 4.222°, Some calculations needs to take place to index this to fit appropriately.

Illinoyance · Nov 12, 2017

Bill D said:
tradition. Same reason they do not use grads or mills today. mills would probably make more sense then degrees.
I asked and was told the US military today uses mills not degrees for the most part. They also use Kilometers not miles.
Bill D

Mils would really unhandy in the shop. A mil is 1/1000 radian. There are 2*pi radians in a full circle. That would never have worked on a machine dial past the first revolution.

I worked for a time in civil engineering. Angles were always in deg. min. sec. Really a pain in the ass. Decimal degrees or grads would have been a hell of a lot easier.

bryan_machine · Nov 12, 2017

Unlike metric powers of 10 versus the random scaling of the inch system, radix 60 (time and angles) systems have some mathematical advantages. In particular 12 and 60 can be evenly divided more ways than 10 can, and to some extent fit more evenly into the length of the day, month, and year.

Remember that we only count in base 10 because we happen to have 10 fingers/thumbs on our hands. If we had 12 (say) we'd surely count in base 12.

Matt Matt · Nov 12, 2017

How come we measure in 40 TPI?
How come we measure in 60 Hz?
How come we measure in 12 V or 120 V or 240 V or 460 V?
How come we measure in Fahrenheit?
How come we measure in inches/feet? Or mph?
How come we measure psi?

I’m sure the French will come up with metric angling soon. LOL.

MattiJ · Nov 12, 2017

Matt Matt said:
How come we measure in 40 TPI?
How come we measure in 60 Hz?
How come we measure in 12 V or 120 V or 240 V or 460 V?
How come we measure in Fahrenheit?
How come we measure in inches/feet? Or mph?
How come we measure psi?

I’m sure the French will come up with metric angling soon. LOL.

They did already long time ago: Gradians.
full circle is 400 gradians. Easier in some ways and worse in some other cases than degrees. (In 80's we had to calculate some examples in gradians in the primary school.)

And just like previous posters said in math and science the radian is most commonly used.

MattiJ · Nov 12, 2017

And anyone battled with Excel probably agrees that decimal time would make things easier

edwin dirnbeck · Nov 12, 2017

When I retire10 years ago, most new drawings were in decimal degrees. Just wondering if ANYBODY IS STILL CLINGING TO D-M-S. Edwin Dirnbeck

batw · Nov 12, 2017

Bill D said:
tradition. Same reason they do not use grads or mills today. mills would probably make more sense then degrees.
I asked and was told the US military today uses mills not degrees for the most part. They also use Kilometers not miles.
Bill D

could be the reason behind the huge costs overruns....

art.h · Nov 12, 2017

I always consider it intolerance when people whine about the units of measurement others use. It also shows the inability to adapt out of your comfort base. For Pete's sake its just that they used a different stick or idea to set up their base. There are many right ways to get any job done, but no 'RIGHT'way.

HuFlungDung · Nov 12, 2017

It is fact that you can lay out a perfect hexagon with a set of dividers. That hexagon will lay inscribed within a circle whose radius equals the length of each of those 6 chords. So that makes 6 a fairly significant number when dealing with layout. And we have 10 fingers so 6 x 10 is sort of natural, too.

I'd have to imagine the ancients weren't stupid and saw that 360 didn't work out for the length of the year, in only a very few years of observation. But hey, you can just fix that with a decree from the emperor every once in a while

The good factorability of 360 is a good reason to use it as a basis.

In modern work, I'd agree decimal degrees make the most sense. I'd bet in most cases, somebody deliberately computed an arctan in deg/min/sec format for the sole purpose of putting a universally accepted dimension on a drawing and their intent is that you will recompute that into an accurate tangent value.

Why are we using QWERTY keyboards? Proven inefficient, yet still persists. I'm surprised that no one has yet invented the bluetooth 'typing glove' where we can type just by flexing our various fingers a little, in various combinations.

Why did machinists EVER start using degrees minutes an seconds?

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