scaling down lumber - Model Railroader Magazine

HO is 1/87th scale. A 2x4 in reality measures 1.5 by 3.5 inches. 1.5 divided by 87 is 0.0172 inches. There are 64 sixty fourths in an inch and 64 times 0.0172 equals 1.1, so any HO two by stock would be 1.1 sixty fourths of an inch thick. You can cut wood this thin on a table saw, but it starts to get pretty flimsy when it's cut that thin.

3.5 inches, divided by 87 equals 0.0402 inches, times 64 equals 2.57 sixty fourths of an inch, or about 1.5 thirty seconds of an inch thick. Because of cell size in woods, the strength to size ratio does not form a linear relationship, smaller wood will not support a proportionally smaller wieght, it supports less than you'd expect when scaling down.

A real purist could get around this by fudging a little on sizes, and by very careful handling of the material, but for most people, different construction methods are necessary.

Most buildings are only visible from the outside, so wall thickness and stud thickness are not an issue. I generally model using wood ripped to between 1/16th and 1/8th inch or about 3/32nds thick. I rip one by fours down to one by three, and glue about four of them together with clamps to form a block about three inches wide by three inches (if four one bys are glued face to face) thick by about two or three feet long.

This roughly square in cross section block is easy to control on a 10" table saw. I stand the glue joints upright and set the fence about where it eyeballs good and rip a test piece. I use a micrometer to gauge thickness, but a tape measure or even your eye will work just as well. Then I adjust as needed, and rip as many as I can before my fingers start getting too close to the blade or until a pusher block doesn't have enough left to work with.

Now I'll have maybe eight pieces of 3/32nds inch thick by three inch wide by two foot long "slabs" of wood as raw stock.

8 feet, divided by 87 equals 0.0919 feet, times 12 equals 1.103 inches. 1.103 inches, minus one inch leaves 0.103 as a fraction of an inch, times 64 equals 6.62 sixty fourths, which reduces to about 3/32 inch. I take my 3/32 inch thick slabs and rip them to 1 and 3/32 inch wide, and now have several feet of building material for eight foot high walls. If a corner of a building requires reinforcement, I'll glue up two pieces of the eight foot wall material at a right angle, and handle it gently while adding a roughly square corner post ripped from the 3/32" slabs.

Different wall heigths can be calculated using similar math, and scales other than HO simply rewquire you divide by a number other than 87 to begin with. The above method, slabs 1 and 3/8" by 3/32" scales out to 8 inches thick, by 7.9 feet tall.

The calculator built into windows under accessories makes short work of the necessary math.