Scale Drawings.

[Sumpter250]

I know that Autocad will scale just about anything that can be imported, or drawn. Unfortunately, my PC is old (Windows 98), and since the hard drive crash, I cannot find a compatible PDF program, so no more PDF's for me, until I can afford a new computer........soooo, I can't verify scaling PDF drawings with Autocad. I have scanned a printed drawing, and used Autocad to resize it. There's a bit of "calculation" that has to be done to determine the scaling factor. The best way is to take the drawing to 1:1 scale in Autocad, and then reduce it to the modeling scale you want. A full size(1:1) drawing, multiplied by 0.0114942 (1/87) 0.011481 (1/87.1) becomes an HO scale drawing.
May I ask why you need "full size, scale drawings"?
A long time ago I purchased a set of proportional dividers. Once I know any measurement from any drawing (or photo), I can set one end of the dividers on that measurement, and set the other end for the exact scale equivalent, and then take off all the measurements directly from the original drawing, regardless of what scale I'm working in at the time. Yes, there's going to be a percentage of error, but then most calipers/micrometers will only take you to +/- 0.001"