Some models use a different order - for example, rake, bevel, slope. In most models the order is bevel, slope, rake. To produce a particular filing, I turn the file three times. Some people file rip saws more or less like this. This file position used on a vertical saw plate with horizontal teeth produces a gullet with zero rake, zero bevel, zero slope. These models are made starting with a file with one side vertical and the base (the lower corner of the vertical file side) horizontal and perpendicular to the saw blade. By sharp I mean how well the teeth slice the fibres of the wood. This angle - 49.2 degrees in this case - is a measure of how sharp the saw is. You cannot see much in this view but you can see one very important angle - the front included angle at the tip of the tooth. The drawing on the left shows the saw teeth from the front - what you see when you look down the line of the teeth from the handle toward the toe. Other filings can be achieved using different types of files - files with a narrower included angle at the corner that goes into the gullet (a cant file). In all cases, both sides of the file are in contact with the tooth on either side of the gullet at the same time. In all models I assume the use of a triangular file. Putting set in a model adds about 50% to the time taken to build the model. Rather, it provides clearance for the saw by cutting a wider kerf that the actual thickness of the saw plate. While set is crucial in saws, it does not change the cutting action very much. All the saws are 0.04" thick.įor even more simplicity, almost all models show saws that have no set. Some appear to depict saws which cannot be prepared with a triangular file.įor simplicity, all the models of cross cut saws are 10 teeth per inch (10 tpi) which are also called 11 points per inch (11 ppi). You will see elsewhere in these pages drawings taken from various books - some the official publications of a famous saw company (Disston). The goal of adding these models to my saw filing pages is to produce drawings that mean something. They also let us compare the un-tooth shape - the gullet shape. If done correctly, the models let us compare the tooth shape for various filings. If any of the models in these pages seems to be out of whack with your intuition, let me know - you may be right. An error in any step produces an accurate scale model, but not the one intended. In that 20 minutes there are perhaps 400 operations of one kind or another - click, drag, specify size, specify orientation. To make a model of a saw filing (the exact shape of the teeth for a given rake, bevel and slope, and the frame of reference in which each rotation is made (more below)) takes me about 20 minutes. If the modeller gets it right, the model is accurate.Īnd there in lies the rub. While free and relatively simple (for a 3D drawing program), Sketchup models are accurate in scale and let you view the model from every angle.īy accurate in scale, I mean that if you specify that a rectangle (for example) has a specific size, then it has exactly that size (within the accuracy of single precision floating point numbers). Google offers a free 3D drawing program called Sketchup.
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