castellated nut and cotter pin is shown at B. In this method the bolt is slotted and a piece of strong and ductile wire is placed in the slot, the lower end of which is formed into a washer to fit between the nut and the surface through which the bolt is passed. When the nut is drawn up tight the end of the wire, which lies into the bolt slot is bent into one of the castellations of the nut. The "Campbell Self-Locking" cotter pin which is shown at Fig. 477, O, has been designed to replace the well-known spring cotter. This is of such form that it may be easily inserted in a hole and when in place it can be locked by hitting the loop or eye with a hammer which drives the short leg down, springing the bent leg and forming a very effective lock. This cotter is made of half round stock, the same as the ordinary type, but has an offset eye and the two limbs forming the body of the pin are of unequal length. The pin may be easily removed when desired by inserting a screw driver blade in the flattened eye and pulling the straight leg out of contact with the bent leg which makes it possible to withdraw the pin. A method of locking a nut which is sometimes used is shown at P. In this a bent plate having a hexagonal hole to fit the nut is held tightly at the other end by a screw threaded into the piece the nut retains or some other fixed part. This is seldom used as it is more bulky and cumbersome than many of the simpler lock washers described. Shop Uses of Arbor Press and Wheel Puller.-One of the useful tools and one of the simplest included in the automobile repair shop equipment is an arbor press that can be adapted to a wide variety of work. A form of press, especially devised for automobile repair shop work is shown at Fig. 478. This has sufficient height so that long pieces may be inserted between the ram and the bed while the supports are spaced sufficiently far apart to make it possible to insert relatively bulky articles. The press' is adjustable as the bed plate may be moved up and down on the side rails in order to vary the opening between the movable member that exerts the power and the work holding portion. The press is also suited for a variety of machine shop operations. The view at A shows the manner of forcing a driving gear off of the shaft of a roll. As will be noted the bed is placed down near the base which makes possible the introduction of the long roller. The gear to be forced off is supported by two iron bars which rest on substantial wooden blocks carried at either side of the roll. The pressure is exerted against the end of the shaft, this forcing the shaft from the gear. The use of the press in straightening a bent rear axle housing is shown at B and on front axle work is shown at D. At C the opera Fig. 478.-Uses of Arbor Press in Automobile Repair Shop. tion of pressing in a bearing cup in a wheel hub is clearly shown. The manner in which relatively small parts may be handled is clearly outlined at E where a gear is being forced off of the armature shaft of a starting motor and at F where the constant mesh gear is being removed from the countershaft of a gear set. The wheel puller is also a very useful appliance, special forms suited for repair shop work are shown at Fig. 479. The type shown at A is a two armed puller having two sets of arms, the lower Fig. 479.-How to Use Wheel and Gear Pullers. set being attached to the upper arm as indicated. This makes it possible to handle work of relatively small diameter that is beyond reach of one set of arms as shown at B or on work of large diameter that would be beyond the capacity or spread of the beam when used as at A. In this case a piece of wood is being used as a spreader for the arms. It is relatively easy to move work near the end of the shaft, this involving the use of only one set of arms as shown at C. The use of the three armed puller, which is a superior form for general service to that shown at C, inasmuch as it is not apt to rock over to one side or the other when the pressure is applied is shown at D. To Make Wood Acid Proof.-Some storage batteries are carried in wooden battery boxes on cars and annoy the owners by leaking or slopping of the acid. To make the wood acid proof take six parts of wood tar and 12 parts resin, and melt them together in an iron kettle, after which stir in eight parts of finely powdered brick dust. The surface to be covered must be thoroughly cleaned and dried before painting with the warm preparation. Sharpening Files.-Lay dull and worn files in a solution of sulphuric acid, consisting of one part acid and two of water. Let them stand over night, then rinse in clear water. Put the acid in an earthenware vessel. To resharpen old files wash them in warm water to remove the grease and dirt, then rinse in warm water and dry by heat. Put 11⁄2 pints of warm water in a wooden vessel, put in the files, add 3 oz. of blue vitriol, finely powdered, and 3 oz. of borax. Mix well and turn the files so that every one may come in contact with the mixture. Add 101⁄2 oz. sulphuric acid and 1⁄2 oz. of vinegar. Remove the files after a short time, dry, rub with olive oil, wrap in porous paper. Coarse files should be kept in the mixture for a longer time than the fine ones. The Cheap Blackening of Brass.-The following solution for blackening brass is nothing new; in fact it has been known for a long time. Owing to its cheapness, ease in working and adapta bility for many purposes, it has been deemed advisable to bring it again to notice. Many platers of course will recognize it as an old solution known to the plating industry for many years, but they may not have realized its advantages for some classes of work. The solution is made as follows: Water Sugar of lead ..... Hyposulphite of soda 1 gallon 8 ounces 8 ounces The solution is used as hot as possible and the brass work is simply dipped in it and allowed to remain until black. This takes about a minute or less. The articles are then rinsed in cold water, then in hot water and dried. If the pieces are scratch-brushed dry, the black deposit will have a high luster. When dipped into the solution, the surface of the brass article becomes yellow, then blue and finally black. The articles should always be lacquered as the black deposit is likely to oxidize and fade if not; but if coated with lacquer, it seems to be quite permanent. For a cheap class of goods that require a black finish, this solution can frequently be used to a good advantage. It requires no electric current used as a dip. The color, to be sure, is not a coal black, but resembles a graphite black more than anything else and has a slight gray shade. It is sufficiently black, however, to answer many purposes and it is so easily applied that it can be used on cheap goods with only a slight increase in cost. Heat-Proof Paint. To make a good cylinder exhaust pipe paint, use two parts of black oxide of manganese, three parts of graphite and nine parts of Fuller's earth, thoroughly mixed, to which add a compound of 10 quarts of sodium silicate, one part of glucose and four parts of water, until it is of such consistency that it may be applied with a brush. Etching. To etch iron or steel mix one-half ounce of nitric and one ounce muriatic acid. Shake well, and it is ready for use. Cover the place to be etched with melted beeswax and wher cold write the inscription plainly in the wax clear to the metal with a sharp instrument; then apply the mixture with a feather, carefully filling each letter. Let remain from one to ten minutes; then throw on water, which stops the etching process, and remove the wax. Use of Tools.-Never use a tap in a cored or rough hole. Run a heavy flat drill through to take out scale, sand or projections. Use plenty of good lard oil in cutting threads with a die. Many times a die tap is ruined the first time it is used, because there was no oil put on the work. Never use taps in any metal without using plenty of good oil. The tap will gauld in any metal and tear the threads off unless well oiled. Never draw a monkey wrench |