Scales and ratios on drawings

alfiewoody · Dec 7, 2016

retraining as been out for a while ... trying to get my head around scaling and ratios on drawings .. is there a technique easy way to grasp ratios / scaling of a room ?

HandySparks · Dec 7, 2016

alfiewoody said:
retraining as been out for a while ... trying to get my head around scaling and ratios on drawings .. is there a technique easy way to grasp ratios / scaling of a room ?

It's pretty straightforward. If a drawing is to a scale of 1:20, then any dimension you measure on the drawing needs to be multiplied by 20 to give the true distance on the ground.

However, if at all possible, go by the dimensions marked on the drawing rather than measuring the drawing.

Leesparkykent · Dec 7, 2016

buy a scale ruler.

alfiewoody · Dec 7, 2016

HandySparks said:
It's pretty straightforward. If a drawing is to a scale of 1:20, then any dimension you measure on the drawing needs to be multiplied by 20 to give the true distance on the ground.

However, if at all possible, go by the dimensions marked on the drawing rather than measuring the drawing.

Thanks mate I appreciate if the scale is on the drawing I can multiply by the scale .. but if there is no scale like pic below do I add all the measurements horizontal and vertical and then measure with ruler to give me scale of doc ?

[ElectriciansForums.net] Scales and ratios on drawings

Richard Burns · Dec 7, 2016

If the diagram is to scale and the measurements are given on the diagram then measure one of the given measurements with a ruler and divide the given measurement by the ruler measurement to get the scale.
So say the 350mm marked on your diagram when measured on the paper was 35mm long then the scale of the diagram is 350/35 = 10 so the scale is 1:10.
you can then check if the 175mm marked is (175/10) =17.5mm long to ensure the diagram is to scale.

alfiewoody · Dec 7, 2016

Richard Burns said:
If the diagram is to scale and the measurements are given on the diagram then measure one of the given measurements with a ruler and divide the given measurement by the ruler measurement to get the scale.
So say the 350mm marked on your diagram when measured on the paper was 35mm long then the scale of the diagram is 350/35 = 10 so the scale is 1:10.
you can then check if the 175mm marked is (175/10) =17.5mm long to ensure the diagram is to scale.

Excellent thanks mate will try that with ruler but like the sound of your logic

HandySparks · Dec 8, 2016

alfiewoody said:
Thanks mate I appreciate if the scale is on the drawing I can multiply by the scale .. but if there is no scale like pic below do I add all the measurements horizontal and vertical and then measure with ruler to give me scale of doc ?

No. To use the example drawing, all the measurements you need are shown on the drawing. What more do you need? Why would you try to work out a scale when it explicitly states "NTS", Not To Scale?

hightower · Dec 8, 2016

@HandySparks has hit the nail, don't need to worry about scale in the posted photo - it already provides the measurements required (in full size), so you just measure out those on the board for your install.