Engineering software, sines and cosines
 

My maths is appalling, I am sorry to say. Yesterday I wanted to work out
the X and Y axis movement on a milling machine to drill two holes opposite
one another skewed 45 degrees from the vertical at a known PCD . I had the
machine zeroed on the centre of the hole around which these drillings were
needed. Took me ages as I have forgotten most of my Trig and I couldn't
find a suitable calculator :( Is there any easy to use engineering software
for this sort of thing? It's at times like this a CNC machine seems
wonderful :) Ta!

Engineering software, sines and cosines
 

On 2010-04-30, Chris Wilson wrote:
My maths is appalling, I am sorry to say. Yesterday I wanted to work out
the X and Y axis movement on a milling machine to drill two holes opposite
one another skewed 45 degrees from the vertical at a known PCD . I had the
machine zeroed on the centre of the hole around which these drillings were
needed. Took me ages as I have forgotten most of my Trig and I couldn't
find a suitable calculator :( Is there any easy to use engineering software
for this sort of thing? It's at times like this a CNC machine seems
wonderful :) Ta!

Almost any scientific calculator from your local discount store should
do trig.

What you need is not just the calculator, you need a textbook on
coordinate geometry and trigonometry. You need to know what to ask
from a calculator.

i

Engineering software, sines and cosines
 

"Chris Wilson" wrote in message
...
My maths is appalling, I am sorry to say. Yesterday I wanted to work out
the X and Y axis movement on a milling machine to drill two holes opposite
one another skewed 45 degrees from the vertical at a known PCD . I had the
machine zeroed on the centre of the hole around which these drillings were
needed. Took me ages as I have forgotten most of my Trig and I couldn't
find a suitable calculator :( Is there any easy to use engineering
software
for this sort of thing? It's at times like this a CNC machine seems
wonderful :) Ta!


If I'm feeling real lazy or its toooo hard I sometimes use my mechanical cad
dwg package to work out distances etc.

Engineering software, sines and cosines
 

On Apr 30, 8:54*am, Chris Wilson wrote:
My maths is appalling, I am sorry to say. Yesterday I wanted to work out
the X and Y axis movement on a milling machine to drill two holes opposite
one another skewed 45 degrees from the vertical at a known PCD . I had the
machine zeroed on the centre of the hole around which these drillings were
needed. Took me ages as I have forgotten most of my Trig and I couldn't
find a suitable calculator :( Is there any easy to use engineering software
for this sort of thing? It's at times like this a CNC machine seems
wonderful :) Ta!

A cheap CAD package would probably do it, or a little work with
memorizing what the trig functions REALLY mean along with a dollar
store "scientific" calculator would do as well. I've picked those up
for as little as $6 from Big Lots. I find the calculator is faster
for most things. Holes in a circle might be the break-point. It also
helps to know that the length of the hypotenuse of a 45 degree right
triangle is the square root of 2 times either side in length, a
special case along with a 30-60-90 triangle. See Pythagorean
theorem. From that it should be dead easy to work out X-Y, even with
a pocket four-banger calculator. Banging away at problems 5 days a
week at 7:30 in the morning for a couple of years will embed this
stuff permanently.

Stan

Engineering software, sines and cosines
 

On Fri, 30 Apr 2010 15:54:19 +0100, Chris Wilson
wrote:

My maths is appalling, I am sorry to say. Yesterday I wanted to work out
the X and Y axis movement on a milling machine to drill two holes opposite
one another skewed 45 degrees from the vertical at a known PCD . I had the
machine zeroed on the centre of the hole around which these drillings were
needed. Took me ages as I have forgotten most of my Trig and I couldn't
find a suitable calculator :( Is there any easy to use engineering software
for this sort of thing? It's at times like this a CNC machine seems
wonderful :) Ta!

http://www.freecad.com/

Engineering software, sines and cosines
 

On Fri, 30 Apr 2010 15:54:19 +0100, Chris Wilson
wrote:

My maths is appalling, I am sorry to say. Yesterday I wanted to work out
the X and Y axis movement on a milling machine to drill two holes opposite
one another skewed 45 degrees from the vertical at a known PCD . I had the
machine zeroed on the centre of the hole around which these drillings were
needed. Took me ages as I have forgotten most of my Trig and I couldn't
find a suitable calculator :( Is there any easy to use engineering software
for this sort of thing? It's at times like this a CNC machine seems
wonderful :) Ta!

Since you have a Windows machine, you already have a decent calculator
as part of the O/S. Just fire up calc, and if it comes up as a
4-function, switch to "Scientific" from the View menu. The setting
should stick unless you have a Naz^H^H^H control freak IT guy limiting
your permissions.

Many enhanced keyboards even have a handy dedicated key to fire it up,
right over the number pad.

BTW, the Windows 7 calculator is fancier with more modes and is more
eye-candy-like than the old reliable XP/Win2k calculator, but they did
manage to break one useful ability of the older calculator. If you do
some calculations in floating point decimal and then want to convert
it to hex, you can't without re-entering the numbers because it clears
when you change from Scientific to Programmer modes. Best to copy the
old one over if this matters to you.

In this case, you could use sin/cos to calculate the y and x movements
required. sin(45°) = cos(45°) = sqrt(2) ~= 0.7071. So if the PCD was
3", you'd multiply the radius (half of that) * sin(45) to get the
y motion required (about 1.061") and for 45 degrees, the x motion is
the same. Then crank the x back double that (2.123") to drill the
left-hand hole, if I understood your description correctly.

Engineering software, sines and cosines
 

On Fri, 30 Apr 2010 15:54:19 +0100, Chris Wilson
wrote:

My maths is appalling, I am sorry to say. Yesterday I wanted to work out
the X and Y axis movement on a milling machine to drill two holes opposite
one another skewed 45 degrees from the vertical at a known PCD . I had the
machine zeroed on the centre of the hole around which these drillings were
needed. Took me ages as I have forgotten most of my Trig and I couldn't
find a suitable calculator :( Is there any easy to use engineering software
for this sort of thing? It's at times like this a CNC machine seems
wonderful :) Ta!


Hey Chris,

Here's your guy !!

http://www.myvirtualnetwork.com/mklotz/

Brian Lawson,
Bothwell, Ontario.

ps..."centre" ??? Where are you?

Engineering software, sines and cosines
 

Brian Lawson wrote:

On Fri, 30 Apr 2010 15:54:19 +0100, Chris Wilson
wrote:

My maths is appalling, I am sorry to say. Yesterday I wanted to work out
the X and Y axis movement on a milling machine to drill two holes opposite
one another skewed 45 degrees from the vertical at a known PCD . I had the
machine zeroed on the centre of the hole around which these drillings were
needed. Took me ages as I have forgotten most of my Trig and I couldn't
find a suitable calculator :( Is there any easy to use engineering software
for this sort of thing? It's at times like this a CNC machine seems
wonderful :) Ta!


Hey Chris,

Here's your guy !!

http://www.myvirtualnetwork.com/mklotz/

Brian Lawson,
Bothwell, Ontario.

ps..."centre" ??? Where are you?


BOLTCIRC.ZIP is the program you want from Mr. Klotz's site. You will have to unzip it and
run it as a cmd line program. Works fine. The output data is placed in a file
boltcirc.dat that you can open with notepad.

Keep in mind that 0 degrees is at 3 o'clock for purposes of orientation 90 degrees at 12
o'clock.

I use Machinist Tool Box PDA on my palm for this but I *can* do it the hard way, just


Wes

Engineering software, sines and cosines
 

On Apr 30, 10:54*am, Chris Wilson wrote:
My maths is appalling, I am sorry to say. Yesterday I wanted to work out
the X and Y axis movement on a milling machine to drill two holes opposite
one another skewed 45 degrees from the vertical at a known PCD . I had the
machine zeroed on the centre of the hole around which these drillings were
needed. Took me ages as I have forgotten most of my Trig and I couldn't
find a suitable calculator :( Is there any easy to use engineering software
for this sort of thing? It's at times like this a CNC machine seems
wonderful :) Ta!

You want a bolt circle calculator. Here's a simple online one (nothing
to load into your computer):
http://www.selectsmart.com/darex/bolt_cir.cgi

Here's its solution to your problem:
2 holes in pattern
Bolt Circle Diameter: 3
Centered at: (0,0)
Starting angle: 45° (45° 0' 0" )
Ending angle: 45° (45° 0' 0" )

( 1.0607 , 1.0607 )
( 1.0607 , 1.0607 )

Engineering software, sines and cosines
 

On Fri, 30 Apr 2010 14:26:44 -0700 (PDT), rangerssuck
wrote:

On Apr 30, 10:54*am, Chris Wilson wrote:
My maths is appalling, I am sorry to say. Yesterday I wanted to work out
the X and Y axis movement on a milling machine to drill two holes opposite
one another skewed 45 degrees from the vertical at a known PCD . I had the
machine zeroed on the centre of the hole around which these drillings were
needed. Took me ages as I have forgotten most of my Trig and I couldn't
find a suitable calculator :( Is there any easy to use engineering software
for this sort of thing? It's at times like this a CNC machine seems
wonderful :) Ta!

You want a bolt circle calculator. Here's a simple online one (nothing
to load into your computer):
http://www.selectsmart.com/darex/bolt_cir.cgi

Here's its solution to your problem:
2 holes in pattern
Bolt Circle Diameter: 3
Centered at: (0,0)
Starting angle: 45° (45° 0' 0" )
Ending angle: 45° (45° 0' 0" )

( 1.0607 , 1.0607 )
( 1.0607 , 1.0607 )

Hmm.. that's two holes in the same location.

You need to start from here, for some reason they didn't put a link
back to the form page that I can see.
http://www.selectsmart.com/darex/bolt_cir.html

I did this (assuming the holes are +/- 45 degrees relative
to 12 o'clock). The program take the x-axis (3 o'clock) as 0 degrees
and CCW angles as positive from what I can see.

2 holes in pattern
Bolt Circle Diameter: 3
Centered at: (0,0)
Starting angle: 45° (45° 0' 0" )
Ending angle: 135° (135° 0' 0" )


( 1.0607 , 1.0607 )
( -1.0607 , 1.0607 )

Engineering software, sines and cosines
 

Excel will do trig work.

=sin(rad_number)
do help in the upper right sin(number) and it shows info...
Martin

Chris Wilson wrote:
My maths is appalling, I am sorry to say. Yesterday I wanted to work out
the X and Y axis movement on a milling machine to drill two holes opposite
one another skewed 45 degrees from the vertical at a known PCD . I had the
machine zeroed on the centre of the hole around which these drillings were
needed. Took me ages as I have forgotten most of my Trig and I couldn't
find a suitable calculator :( Is there any easy to use engineering software
for this sort of thing? It's at times like this a CNC machine seems
wonderful :) Ta!

Engineering software, sines and cosines
 

On 2010-04-30, wrote:
On Apr 30, 8:54*am, Chris Wilson wrote:
My maths is appalling, I am sorry to say. Yesterday I wanted to work out
the X and Y axis movement on a milling machine to drill two holes opposite
one another skewed 45 degrees from the vertical at a known PCD . I had the
machine zeroed on the centre of the hole around which these drillings were
needed. Took me ages as I have forgotten most of my Trig and I couldn't
find a suitable calculator :( Is there any easy to use engineering software
for this sort of thing? It's at times like this a CNC machine seems
wonderful :) Ta!

A cheap CAD package would probably do it, or a little work with
memorizing what the trig functions REALLY mean along with a dollar
store "scientific" calculator would do as well. I've picked those up
for as little as $6 from Big Lots. I find the calculator is faster
for most things. Holes in a circle might be the break-point. It also
helps to know that the length of the hypotenuse of a 45 degree right
triangle is the square root of 2 times either side in length, a
special case along with a 30-60-90 triangle. See Pythagorean
theorem. From that it should be dead easy to work out X-Y, even with
a pocket four-banger calculator. Banging away at problems 5 days a
week at 7:30 in the morning for a couple of years will embed this
stuff permanently.

If you have a scientific calculator like the HP-15C which has
polar to rectangular and rectangular to polar conversions it is dead
easy. Assume that the first hole is on the X axis in line with the
center hole, and you will be putting an integer number of holes evenly
spaced around the center hole. Divide the number of holes into 360 to
get the angular increment (6 holes is 60 degrees per hole, the most
common arrangement). Key in the angle (60 degrees) and the radius (say
a 4" circle of holes would have a radius of 2", and then hit the P-R
button and this puts the second hole at 1.0000" X and 1.7321" Y. Add
another 60 to make 120 degrees, and repeat with the same radius and you
get -1.0000" X and 1.7321" Y. Another increment is 180 degrees, and
gives -2.0000" X and 0.0000" Y exactly opposite the first hole which was
our starting point, not calculated. Continue for another 60 degrees and
you get 240 degrees, -1.0000 X, -1.7321" Y, and another 60 degrees makes
it 300 degrees, 1.0000" X and -1.7321" Y. Note that with six holes, the
numbers start to look very familiar fairly quickly.

Now if you were to go for something like 7 holes 51.4286 degrees
per increment, things will look pretty ugly after the starting point of
2.000 X, 0.000 Y. Let's put them in table form for this one.

hole# Angle X Y
0 0 2.0000 0.0000
1 51.4286 1.2470 1.5637
2 102.8571 -0.4450 1.9499
3 154.2857 -1.8019 0.8678
4 208.7143 -1.8019 -0.8678
5 257.1429 -0.4450 -1.9499
6 308.5714 1.2470 -1.5637
7 360.0000 2.0000 0.0000

Note that hole #7 is back to the beginning.

You'll still see some repeating numbers with different signs,
but not as many as with six.

If you don't want to start with your first hole on the X axis,
you can do something like divide the increment by two and calculate
every hole. For a 6-hole circle this will give equal spacings of first
and last hole above and below the X axis, and put the 2nd and 5th holes
on the Y axis. Or, you could divide the starting angle by four and miss
all of the axes. All depending on what you want.

While I can't set my machine to 0.0001" increments, I calculate
to four significant figures (especially when generating it all
mathematically) to get a feel for which way to round. :-)

If you want to write a program in BASIC or C or most other
languages, beware that the default angular measurement is radians (2 pi
of them per full circle) so you will have to convert your degrees to
radians before calculating.

In a spreadsheet, you might have degrees available. Check what
you have. Take the arc sine of 0.707 (which should come out close to 45
in degrees.) If you get 0.7852 or close, you are in radians. If you
get almost 50, you are in gradians (100 per quarter circle, or 400 per
full circle).

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

Engineering software, sines and cosines
 

Chris Wilson wrote:
My maths is appalling, I am sorry to say. Yesterday I wanted to work out
the X and Y axis movement on a milling machine to drill two holes opposite
one another skewed 45 degrees from the vertical at a known PCD . I had the
machine zeroed on the centre of the hole around which these drillings were
needed. Took me ages as I have forgotten most of my Trig and I couldn't
find a suitable calculator :( Is there any easy to use engineering software
for this sort of thing? It's at times like this a CNC machine seems
wonderful :) Ta!

download KwikTrig. Free and easy