I sincerely hope this is the right forum to ask this question. I am making some PCB's and I have a drill plot chart they are 30th and 40th. I assumed it was imperial and looked for a conversion calculator on line. And failed.


I need to know how to convert a measurement shown in th to mm

Thanks

 

hi R..

(40thou /1000)* 25.4 =1mm

E

 

hi R..

(40thou /1000)* 25.5 =1mm

E

That acutally is times 25.4

 

That acutally is times 25.4

Thanks for the heads up... a silly typo!

E
Will correct

 

Or;
thou *0.0254
works just as well and is only one operation.

 

hi Roman,
The OP appeared in some doubt what a 'thou' is, ie: 1 thousandth of an inch, so thats why I used the 1000 multiplier in order to reduce the 'thou' to inches, 40th *1000 = 0.04 inch.

Eric

 

If your interested, one of the best simple calculators I've found was written by Joshmadison. Its simply titled Convert. I've used it for several years. It's a small program, bug free, and you can make custom tables with it if you like.

I hope I didn't violate protocol.

HTH,
Gary

 

Hello,

1 Thou (UK) or 1 mil (US) is 0.001 Inch or 2.54E-5 m according to the following tabe:
http://www.allmeasures.com/table.asp?distance_length=on&Submit=Conversion+Table
There is also a converstion calculator:
http://www.allmeasures.com/conversion.asp?distance_length=on&Submit=Converter

All tables can be found here:
http://www.allmeasures.com/

Bertus

 

I use google for most of my conversions, for example type 67 mil in mm and it will give you the answer straight away. And if you use the little search box next to address bar you don't even need to press enter (in firefox at least).

 

On my computer with Mac OS 10.6.8, dragging my mouse to the lower right corner brings up some maintenance things, but also a simple converter that I often use.

For more, I use this: http://www.onlineconversion.com/

 

Most ECAD system let you switch between units. Like do your board layout in using the units mils. But then switch to the metric system. Then going over your board with the hole size editor. If that is preferable

 

This is why we should all use the metric system!

 

Agreed! Everyone but cavemen should be using metric.

Cavemen can still use bushels and furlongs and sheckels while they scribble email on the cave walls.