# Thread: using inches and mm in same drawing

1. ## using inches and mm in same drawing

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I cannot find the answer to this in any of my autocad 2000 books..Lets say I draw a circle,1/8th inch in diameter..properties say that it is a circle with diameter of 1/8th inch...now I want to make a rectangular array with collums being 10 and rows being 2...but with a spacing of 40 miilimeters for the collums and 20mm for the rows...how do i tell autocad the spacing needs to be millimeters....it keeps trying to draw in inches..I tried typing in 40mm but it rejected that I do not want to get out the calculator and do some sort of conversion such as 40/25.4=1.5748 inches..cannot I just type in millimeters when it is needed some how...In all of I done so far trying to learn this program,I have never mixed the 2 unit types together..it has always been inches and feet...but not inches and mm both together..Mike

2. You can only use one unit or the other. Acad thinks in drawing units, not mm or inches. It is you who decides what units you want 1 acad drawing unit to represent. From then on it's that unit, so you will have to convert one to the other if you want to use 2 different units. Sorry, but that is how acad works, in drawing units.

3. Yea,that is what I was afraid of..all right then.I will see what I can do..thank you very much for the reply Alan...Mike

4. Cheers, mate.

You could always enter the mm converted to inches using a quick bit of lisp code.

Enter 40mm as (/ 40 25.4)

5. i use this program to do my converting, much quicker than a calc and its free:

6. Well here is what I am trying to do..I have a little cnc mill and I am trying to drill holes into a metal plate..1/8th holes...with the spacing I described above...I need those hole spaces to be exactly 40 mm wide..trying to convert it using 25.4 or using 25.41245(or what ever the number is) could cause the the distance between the 1 and 10th hole not to be exactly 400 millimeters distant..and then the bolts will not screw into the plate because of the error factor in the distance between each bolt..doing a conversion to inches could cause the 1st and last bolt to have a distance of 395 mm instead of 400..

When I draw a simple line randomly setting the end points,then look at the properties of the line..if the units are set at architectural..20'-8"5/16...how do I set the drawing up in the beginning for it to say that distance to be in metric...20M-279mm...20meters-279millimeters..a real world distance like it is doing with feet and inches

7. Rebel..I down loaded the program and that is what I need to get it done.Thank you very much for that..40 millimeters is 1.5747984 inches..close enough I would say!!!

..cannot I just type in millimeters when it is needed...
Doesn't help you in AutoCAD, but in a modern mechanical design program like Autodesk Inventor or SolidWorks you can simply enter needed units at any time.

Well here is what I am trying to do..I have a little cnc mill and I am trying to drill holes into a metal plate..1/8th holes...with the spacing I described above...I need those hole spaces to be exactly 40 mm wide..trying to convert it using 25.4 or using 25.41245(or what ever the number is) could cause the the distance between the 1 and 10th hole not to be exactly 400 millimeters distant..and then the bolts will not screw into the plate because of the error factor in the distance between each bolt..doing a conversion to inches could cause the 1st and last bolt to have a distance of 395 mm instead of 400..
What you need to do is locate the first hole then the last hole 400mm away. Draw a line from center of hole to center of hole and use _DIVIDE to equally space the holes.

When I draw a simple line randomly setting the end points,then look at the properties of the line..if the units are set at architectural..20'-8"5/16...how do I set the drawing up in the beginning for it to say that distance to be in metric...20M-279mm...20meters-279millimeters..a real world distance like it is doing with feet and inches
You will only get 20.279M or 20279mm

Originally Posted by Rebel
i use this program to do my converting, much quicker than a calc and its free:

I use the exact same program for conversions.

Originally Posted by JD Mather
Doesn't help you in AutoCAD, but in a modern mechanical design program like Autodesk Inventor or SolidWorks you can simply enter needed units at any time.
Inventor is much better suited for this type work.

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Originally Posted by Rebel
i use this program to do my converting, much quicker than a calc and its free:

"Click 'n Convert" at
http://www.haywardflowcontrol.com/pages/down_cnc.html

I've used this one for years, keep an icon on the desktop.

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