scaling off parts manual

[Ashman]

Hi guys,
I am fairly new to this so sorry if this is a silly question but I have just set up my little workshop and am looking to start a scale 1:10 D9R as I can get access to a parts manual and service manual from my quarry site office. I have looked at the parts manual and have got the design but alas no dimensions to work off. I was just wondering how you guys with the awesome machines were able to get dimensions to scale from? any help woild be great. Thanks.