Take a few minutes to read this and then take an hour to make an inch. I make my own tools, therefore I have to make my own rulers, I don't have to but I can. This is a copy of an antique original in the collection of a friend. I have made several of these over the years, some how I need to make another. It is not that they wear out, people just talk me out of it when they see it.
You will require a hacksaw and a triangular shaped file, also a cold wood carving chisels and a hammer. You need a rectangular piece of metal, soft steel, wrought iron, any easy to work hard ferrous metal. It needs to be 1 inch wide, its thickness can vary as can its length. One-quarter inch thick is a good size and 5 inches is a good length. One end needs to be flat, square and smooth. Dress the end on all sides to form a perfectly square rectangle with sharp edges. Next mark out 8 equal spaces on the top edge and make a nick with the edge of a triangular shaped file. In the nick, saw a kerf in the metal, squarely across the thickness of the stock about 1/8” deep. Use a hack saw to make these cuts. Next with a triangular shape file, shape the 9 projecting nibs to sharp pointed teeth. They should all be 1/8” apart. The cold chisel and hammer can be used to set the teeth in their proper place. Once you are close you want to file the height or size of the teeth. This is done on one long edge and all teeth except each end is reduced in height or size by about 1/16”. Next all teeth except the ends and the center are reduced another 1/16”. Next the teeth in between are reduced another 1/16”. This makes each end largest in size, the ½” is next largest, then the ¼” and ¾” are the same size and the 1/8”, 3/8”, 5/8” and 7/8” are all the same size. This produces a distinctive easy to read pattern when stamped into wood. If you need to know 1/16” measurements, they are the ones directly in the middle between the adjoining marks. One side will be straight and the other will be stair stepped or crenellated.
Finish sharpening and shaping the teeth and test the inch stamp and adjust the teeth with the cold chisel and hammer. This method is trial and error, sometimes when you set one tooth right, you move the adjoining tooth inadvertently. Check the teeth repeatedly to make sure they are all on their mark. Use a scrap of wood that you will be using most and test the teeth for a proper mark. The marks show up better on lighter colored harder woods. The sharp teeth will cut the wood fibers and these cuts can be stained to make the marks more distinctive. Slightly round and dress the other end of the stamp where it will be struck with the mallet.
When using the stamp it is a good idea to mark out your marks with a known accurate ruler on the one-inch marks. The stamp can crawl or creep while you are working down the length of a ruler you are marking and will end up too short or too long, usually too short. Use a sharp cold chisel to make the marks at each one-inch location; this will give you a positive reference point for stamping. Use a mallet instead of a hammer; it produces a better blow without the bounce. I always place a punch mark on the flat side of the punch so I can always have the same register when in use. Now if your measurements are off you can’t blame the ruler. After you have used this stamp 63,360 times you will have stamped a mile. Give them an inch and they'll make a mile.
