How to scale out 1/12th scale

All the above advice is good. In addition, get a set of digital calipers and never leave home without them. It will save you fussing around with fractions, and you can convert from imperial to metric easily. a simple rule of thumb for 1/24 scale is that 1" = 1mm, so double it for 1/12 scale and 1" = 2mm

While just dividing all the original specs by 12 is the easiest way to go (because 1'=1"), you'll sometimes get less-than-accurate measurements.

I find that when doing scaling, the most accurate way is to convert everything to millimeters and then divide that by the scale.  It mostly comes down to trying to scale fractions of an inch, up and down.  Say an actual measurement is 8' 3 and 3/8".  Okay, on 1/12 that's 8" + whatever 1/12 of 3 3/8" is.  Whereas you convert that to mm and divide by 12, you'll get a much cleaner answer.  Even if you round off a fraction of a millimeter, the largest margin of error (in 1/12) should only be 6", if you were to scale back up to full size.

-Fred

No but you can multiply by 24, and divide by 12.....

jim A

Boba Fett wrote:

Well, for 1/12, and you're used to 1/24...I think you can just double the size... am I wrong?

Nope.

heres a conversion chart I use for 1/32 scale. It works fine all the way around I think.

http://jbwid.com/scalcalc.htm

Here's a scale calculator by Frank Crenshaw (on HS).......(clean, no bugs) Great program..

http://www.clubhyper.com/reference/calculatorfc_1.htm 

There probably is such a thing on the web somewhere, but it shouldn't be necessary.  1/12 scale is one of the easiest to work with.  It's the equivalent of 1"=1'.  So every inch on the model is equal to a foot on the prototype.

One of the most useful tools for model building is an electronic calculator that works in feet, inches, and fractions of inches.  Such things used to be rare; I've got one that I bought at Radio Shack about twenty years ago for about $35.00.  (It still works perfectly.)  Nowadays you can pick one up at Lowe's, Sears, or even Wal-Mart for as little as $7.00. 

With such a gadget at your disposal, just key in the prototype dimension and divide it by 12.  For instance, suppose some part of the original car is 1' 7 5/16" long.  On my old calculator (the keystrokes may be different on others), I key in 1 FT 7.5/16 IN , then divide by 12 to get the answer, which is 1 39/64".  (This particular calculator works in fractions down to 1/64".  I suspect you'll find that's close enough; it is for me except on extremely rare occasions; if I do need to work to tighter tolerances than that, I can always use thousandths of an inch instead.)

Sometimes it's more convenient to use the decimal system.  This particular calculator has a key that converts from fractions to decimals in one stroke; the aforementioned 1 39/64" is equal to 1.609375".

When I bought my little Radio Shack calculator it was necessary to buy a separate gadget to convert from the English system to the metric system.  A few months ago I found one at Wal-Mart for $7.00 that does that conversion with one stroke. 

Believe me, for any serious modeler a calculator like that will be an excellent investment.