When Dan Eice invented that famous joke about “the greatest saw to saw that he ever saw saw,” certainly the saw that he saw saw bore no sort of resemblance to many of the saws which we see saw. Saws that saw one's nerves as well as the timber, screeching and gnawing through wood instead of cutting it smoothly and sweetly, that make one's back to witness their operation, and heart ache to witness the useless expenditure of power and labor in much of the work performed by this useful and, when made, filed, and set, most effective tool. A saw is a series of cutters, arranged either in one line or in two lines, according to the work to be performed; and all saws used in wood work (and it is such of which we speak) may be included in two classes—those which cat across the grain and those which cut lengthwise of the grain. The latter class has its teeth or cutters formed so as most to resemble a narrow chisel or plane bit. The teeth of the former Mass may be regarded as knives which cut, or ought to cut the sides of the kerf smoothly at the same time that they force out or split off the intervening wood. Many mechanics are accustomed to take their saws to a professional saw filer and setter, acknowledging their own inability to perform the operation as it ought to be done, and preferring to incur expense rather than use a badly-sharpened tool. There is no necessity for this, and any man of ordinary intelligence and skill in the use of tools may easily acquire the simple art of saw filing and setting. In order to do this, the following points must be observed: The teeth in cross-cut saws ought to cut both ways in traversing through the wood, and the teeth of both cross-cut and rip-saws .should be as near as possible of equal length and sharpness. The bevel on the tooth should be more acute for than for hard wood. In order to secure the same bevel on all the teeth of a cross-cut saw the file must be held at the same angle in filing each tooth, and if the saw has been previously well filed, the same number of strokes of the file will be required for ea oh tooth, provided an equable pressure is Ifthe teeth are uneven in length, their points ought to be first leveled with a flat file, and the beveling be subsequently governed by the point. As soon as the point becomes well defined on each tooth, provided the proper bevel has been maintained throughout, the operator should proceed to the next tooth, and so on. The saw should be filed from the handle toward the point, as in no other way can a proper bevel be obtained and maintained throughout. It a cross-cut saw be found a little high in the middle, it may still work well, but in no case should it be lower in the middle than at the ends. The feather should be taken from the sides of the teeth by a straight, flat file, or a whetstone with a plane surface, laid along the sides of the teeth, and drawn smoothly along without much pressure. This may be done after the setting. A rip saw will be found to work better in all kinds of wood if filed a trifle beveling, although in perfectly straight-grained wood it will work well if filed straight across. This bevel is best given to the toeth of these saws alter they are set the file being held at right angles to the teeth. Hard wood requires more bevel in the teeth of a rip saw than soft wood. The setting of a saw is a matter of great importance. A large proportion oi tla power required in working a saw is caused by the friction of the plate on the of the kerf, and it is the object of setting' to lessen this friction by increasing the width of the kerf. making of saws thinner at the back than at the cutting edge is sound and saves much power that would otherwise be expended in friction. A difference of opinion prevails among mechanics about the best way to set saws, some maintaining that the hammer and punch are superior to any of the patent setting tools now in use. A series of experiments which we saw performed some years since convinced us that the hammer and punch were imperfect tools for this purpose, although there is no doubt that the principle of the hammer and punch, as applied in some of the saw-setting tools which have been invented, is the best. A tooth bent and set by a blow will remain where it is put. This, on the contrary, cannot be said of teeth which are bent by sets which act on the lever principle. Neverthe less, we have seen saws very perfectly set by the latter kind of tools. Whatever means are adopted uniformity is the ob ject to be secured ; the amount of set required being dependent, of course, upon the nature of the work the saw i intended to perform, and therefore a matter to be left to personal judgment.
This article was originally published with the title "How to File and Set a Saw" in Scientific American 21, 16, 252 (October 1869)