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TAE Marine. REVIEW 39 A NEW BAND SAW FILER. The New Britain Machinery Co., New Britain, Conn., has recently brought out a device for filing band saws, which is shown herewith. It is claimed by the maker that the band saw that is filed by hand cuts better than one filed by ma- chine, and the present device has been brought out to ac- complish hand filing in the easiest and quickest manner. In order that a band saw blade should cut free and for. the longest time without attention, it must be sharpened with regard to four conditions. First--It is most essential that the tooth must be sharp- ened squarely across. To do this the file should be held \ SSRN AUANS yy] DEVICE FOR FILING BAND SAWS. perfectly level at a right angle with the saw, otherwise the cutting points of the teeth on one side of the saw will be in advance of those on the other side and the saw will not follow a line but will lead to one side. Second.--The top of the teeth should be filed last. The end to be gained by this is a shape of tooth such as shown in Fig. 2. If this is not done the teeth will be similar to those shown in Fig. 3, having a burr on the point. which will drag, and soon break off, leaving the saw dulled. Third--The desirable amount of hook to the tooth should be determined and maintained. As much hook as can well FIG: -.: be given by a three-cornered file cuts the best and the saw will clear itself in ordinary work on dry and short grained woods. Less -hook is desirable on wet or stringy woods where straighter teeth work better. Fourth--The teeth should have even jointing that full ef- ficiency may be obtained from each cutting tooth. The art of filing consists largely in acquiring the feel of the file when working horizontally. In this the eye is not much of an aid, as no one, while working, can stand at one side and view the file to see that it is held level. The New Britain filer has been devised to enable one to fill the above conditions. With this device the file is guided mechanically in a horizontal direction and also prevented from turning in the hand. These guided movements determine the contour of the tooth, remove any tendencies to variations in the shape, and limit the personal skill required. The operator is simply - called upon to see that the file goes squarely across, and the eye is sufficient guide when above the file for square filing. The device consists of a vise which can be quickly clamped to a. table, but in which the saw is not clamped between every few teeth. A spring with adjustments and cast-off serves to regulate the pressure of the accurately hardened and ground jaws, which are guaranteed to hold any saw without chattering. A slight pressure of the file from right to left will carry. the saw along with it, as the pressure in this direction tends to release the jaws enough to allow the saw to slip and when the pressure is removed the saw is firmly held as above noted. This feeding feature is regulated by a stop pin at the right of the fixed jaw, which prevents overrunning of the file when sharpening or feeding as described. The saw, however, can be easily released when desired by a touch of the lever at the right of the device. ' There is but one adjustment to make on the vise itself ' ordinarily, this being to set 'the under gauge to the back of the saw so that the teeth will project enough to allow the file to pass through freely. The gauge works in parallelism and is held by a single thumb screw. No- adjustment for different thicknesses of saws is necessary, as the vise auto- matically clamps any ordinary gauge of saw. A special file is furnished with the device, which has rounded corners that prevent checking or cracking of narrow band saw blades, which frequently break from the sharpened corners at the gullet of the teeth as left by sharp-edged tools. The point of the file is carried in .a roller guide device which holds the same to any level required and which may be ro- tated to the proper angle for any desired hook to the teeth, These two adjustments of the file may be changed with re- lation to each other or they may be fixed and the file firmly clamped by set screws. The hardened rollers on the polished plate do not impede the action of the file, although they con- trol and guide it. : Figs. 2 and 3 show teeth which have been filed by ma- chine and filed by hand. In Fig. 3 the burr thrown up, is clearly seen, and which should be removed by hand filing, before the saw is used. INSPECTORS' TESTING AND PROVING OUTFIT. The Ashton in- spectors' testing and ¢ proving outfit, illu- strated by the accom- panying cut, is par- ticularly designed to meet the require- ments of boiler and power plant inspect- ors, mechanical and chief engineers, as it is accurate, durable, light weight, and easily portable. The outfit consists of the -- following nickel- plated instruments: Three-inch standard test gage, screw test pump, gage hand puller, hand set, lever handle union gage cock and screw driver, all neatly and compactly contained in velvet-lined leather case, fitted with lock and handle. The approximate weight of this outfit is 8 Ib. ASHTON PROVING OUTFIT. George Morrell, general manager of the Seattle Ship- ping Co. of Seattle recently visited San Francisco to negotiate for additional vessels for the Nome trade.