Model Building Basics: Scale Dimensions
By Dave Tallon, Tallon Custom Collectables

One of the first topics usually discussed when two or more collectors meet is their preferred scale. Many collectors seem to be almost as passionate about their scale preference as they are in their preferred brand of tractor. Despite the frequency that the term "scale" is used in the hobby, many collectors, especially the younger ones, don't understand how it works. This month, I will take a look at the various scales in the farm toy hobby, and explain the concept behind it.

Scale is one of the most fundamental aspects of the farm toy/model collecting hobby. It is by scaling dimensions that we can accurately represent large machines on a piece of paper or in models that can fit on our display shelves. The scale is usually represented as a fraction, like 1/64, or as a ratio, like 1:64. What this means is that 1 unit of length on the model represents, in this case, 64 units of length on the real thing. For example, if you had a real tractor with tires 64 inches tall, they should be 1 inch tall on your 1/64 scale model. Unfortunately, the math isn't always that easy, but it is still fairly simple. Take the real-life dimension you are interested in, and divide it by the scaling factor. Here is another example:

Scale is one of the most fundamental aspects of the farm toy/model collecting hobby. It is by scaling dimensions that we can accurately represent large machines on a piece of paper or in models that can fit on our display shelves. The scale is usually represented as a fraction, like 1/64, or as a ratio, like 1:64. What this means is that 1 unit of length on the model represents, in this case, 64 units of length on the real thing. For example, if you had a real tractor with tires 64 inches tall, they should be 1 inch tall on your 1/64 scale model. Unfortunately, the math isn't always that easy, but it is still fairly simple. Take the real-life dimension you are interested in, and divide it by the scaling factor. Here is another example:

According the Steiger Panther 1000 brochure, the real tractor is 281 inches long.

To see how big this should be in 1/64 scale, you take that dimension and divide it by 64.

The result is 281 / 64 = 4.4 inches.

As you can see, the Scale Models Panther 1000, at 4.2 inches long, is just a little smaller than 1/64 Scale.

One thing that can complicate this math is if the real-life dimensions you have are in different units than the ones you want to work with on your models. For example, if you are wanting to scale a 30 foot combine header to 1/32 scale, you will come up with 0.9375 feet. Chances are, your ruler doesn't have a marking for that. However, if you first convert 30 feet to 360 inches, (30 ft * 12 inches / 1 ft = 360 inches) you come up with a scale measurement of 11.25", or 11 1/4". Further complicating matters is if one dimension is in metric and the other in standard, or vice-versa. A conversion must be done in this case also prior to doing your scale calculations. Rather than go through examples of the various conversions you might have to do, here is a link to a simple program that will do the converting for you.

Typically when calculating scale dimensions for a project, I need to look at several dimensions like length, width and height, all at the same time. The attached Microsoft Excel spreadsheet can help you do the calculations for one or more dimensions. There are three tabs to the spreadsheet to handle three different scaling scenarios.

Tab 1 – “Scale Dim”
Use this tab when you know the real-life dimensions and want to convert them to a given scale. This is useful in instances where you have the dimensions from a brochure for example, and want to calculate what the dimensions should be for a scratch-built or customized scale model.

• Input: Real-life Dimensions, Scale
• Output: Scale Model Dimensions
• Example: This is the type of calculations I had to do when I built my 1/64 Caterpillar 2-Ton from scatch.  I knew the real model was 108 inches long, so in 1/64 scale my model had to be 1.7 inches. 

Tab 2 – “Real Dim”
Use this tab when you want to calculate what size a model of a given scale would be in real-life. This is particularly handy in cases you have a “generic” scale model that doesn’t represent any particular real-life model and you want to know how big it would be if it were real. 

• Input: Scale Model Dimensions, Scale
• Output: Real-life Dimensions
• Example: Ever wonder how big a disk the Ertl wing disk represents? Using this sheet you can calculate it.  At 4.5 inches in 1/64 scale, if it were real it would be 288 inches, or 24 feet wide.
  

• Input: Real-life Dimensions, Scale Model Dimensions
• Output: Scale
• Example: I wanted a "heavy duty" pickup to display with my 1/50 scale construction models, but vehicles in that scale can be hard to find.  I ran across an Anson Chevrolet Dually that looked like it might work, even though it was listed at 1/43 scale.  A quick comparison of the dimensions of the model (5" long) to the dimension of the real truck  (247" long) revealed the model's true scale of 1/49, a nearly perfect match to the construction equipement.