Re: Conversion percentages.

Rod Miller

Hi Denny,

The method Jerry White showed me was to draw/tape a line that was a
specific length in the scale of the image to be enlarged/reduced.
E.g., an O scale (1:48) drawing would have a line, say, 2.5 inches
long which represents e.g. 10 feet.

Start with an approximate enlargement/reduction setting and make a
copy. Measure the length of the line on the copy and determine its
scale length for the scale you want. When the line is 10 e.g. feet long
in the scale you want, you have the correct reduction/enlargement.

E.g., suppose you want to reduce an O scale (1/4 inch = 1 foot) drawing
to S scale (3/16 inch = one foot, or 1/64 inch = 1 inch).

A 10 foot long line in O scale is 10 1/4s or 2.5 inches long.

A 10 foot long line in S scale is 120 1/64s or 1 7/8 or 1.875.

When your line on the copy is 1.875 inches long the copy is accurate
for S scale.

IMHO that is more accurate than calculating a reduction/ enlargement


Rod Miller

Message: 18
Date: Wed, 18 Jan 2006 13:51:26 -0800
From: Denny Anspach <>
Subject: Re: Conversion percentages.

Off hand, does anyone know what percent rule of thumb reduction (e.g.
as would be set on a copying machine) to accurately reduce S-gauge
plans to HO (1:76 ---->1/87.1)?


Denny S. Anspach, MD

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