Autocad units

[carl289]

I received a drawing of an os map which is in inches but when you measure between 2 points it is in metres.
I have tried to change the units to mm and the scale to 1:1 but the drawing does not appear to change to mm although in the drawing units box it states mm, and the scale box states 1/64 = 1-0.
When the drawing set up box appears i have ensured the Scale model space objects in current drawing to reflect new units is ticked. But this totally throws the dimensions out and the grid co-ordinates do not correspond with the OS map

Anyone have any suggestions?

Thanks Carl

[winters.david]

best thing to do is to open a new drawing setup in mm .
and copy clip the total drawing to the new drawing .
autocad will read the inches to mm .