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hooks at the ends formed on curves of different radii. The one having the more gradual curve is used first to start the key while the one having more abrupt curve is employed for withdrawing it. When the key puller is placed between the head of the key and the hub of the flywheel a cam action is obtained by which the pressure of the hammer blows on the other end of the key puller is increased
Fig. 469.—A—Removing Jib Key. B—Method of Truing Crankshaft.
C—Repair of Gear Case with Babbitt Metal. D—Use of “Putting-
many times and the key easily started. If the key is rusted in place or if it has not been removed for a long time it may be found desirable to heat the end of the shaft with a blow torch or to soak the rusted parts with kerosene.
Truing Crankshaft.-The method of holding a crankshaft when it is desired to true the crank pin journal shown at Fig. 469, B, is a very practical one and is followed by a number of mechanics when overhauling an engine. The journals are often not roughed up enough to warrant dressing them down in a lathe, so the crankshaft may be securely clamped in a vise between wooden blocks and the journals dressed down with strips of emery cloth or with a leather belt or strap covered with oil and abrasive material.
Repair of Broken Gear Case.-An emergency repair of the gear case that has been injured by a nut falling between one of the gears and the bottom of the case is shown at Fig. 469, C. The repairman who made this repair did not have an autogenous welding outfit so the hole was filled up with babbitt metal as shown.
A Putting-on Tool.-How often at some time or other, have mechanics wished for something in the way of a putting on tool! As it is always easy if a piece is too large, to remove metal in order to bring it to proper size this proposition does not worry even the poorest mechanics. But what is to be done if the piece is too small? A common method and a brutal one is to take a center punch and upset the surface of the metal, in order that it shall be a tighter fit in the hole. A bushing or a rod, if not too small, is often treated in this manner, and may be forced into the hole. A more effective method of “putting on” is by means of a common coarse knurl, knurling the bushing the entire circumference in several places. This will have the effect of expanding the outside diameter almost 1/32 of an inch, if desired, and is much neater and infinitely superior to the use of prick punch marks, which is an unsightly and unreliable method of increasing the effective diameter. The great advantage of knurling is that the metal is equally and uniformly expanded, does not look bad if for any reason the bushing or rod is withdrawn and what is more important for anything that must be a tight fit, it will never work loose.
Illuminated Magnet.-An electric searchlight and electro-mag
net has been brought out by an English concern and should prove a useful tool in repair shop. It consists of a handle, on one end of which is the magnet, while above the latter is an electric bulb which sends light through two windows, as presented at Fig. 469, E. А flexible cord passes through the instrument and is attached to a storage battery or dry cells. The magnet is utilized to pick up nuts, bolts or pieces of metal that may drop into the crankcase or other places not easily reached by hand, and is said to be sufficiently powerful to attract a good sized wrench. The light facilitates finding the parts, may be used to ascertain the amount of gasoline in the fuel tank or lubricant in the crankcase and to inspect other places. In addition to being handy in the garage it could be included in the tool equipment of a car and used in connection with the roadside repairs.
Simple Priming Device.-Several simple priming devices may be constructed by anyone of average mechanical ability to facilitate motor starting in cold weather. One such equipment is shown at Fig. 470, B, and comprises a dash priming cup, tubing connecting it with the intake manifold, and a spraying device, which is shown separate in the drawing. It will be noted that the last named member is perforated. To utilize the primer a little gasoline is poured into the cup on the dash and the lever turned slightly to admit the fluid, also a little air. The fuel flows through the tube to the perforated member, and upon cranking the engine, the air drawn in through the carburetor and petcock breaks up the fuel, converting it into a rich mixture. It is stated that the motor will start on the second or third crank even in the coldest weather. The material required to install the primer consists of a petcock, which is secured to a plate on the dash; a connector having a tubing and a pipe thread end, 1/4-inch annealed copper tubing, and a union. To the last named is soldered a piece of brass tubing which is drilled full of No. 62 drill holes. Its length should be approxi. mately that of the diameter of the intake pipe into which is inserted by drilling and tapping a hole. The manner of installing the parts is clearly depicted in the drawing. It is stated that the equipment described can be made at a slight cost. A simpler installation is shown at A, this consisting merely of a petcock
threaded into the intake manifold. It has the disadvantage that it must be reached to be filled by raising the hood. The owner of a model T Ford states that he has obtained increased mileage by the use of the primer, as the petcock on the dash may be opened to admit auxiliary air. In average running in warm weather he has secured 26.5 miles to the gallon, and 32 miles in long trips.
Fig. 470.-A-Simple Priming Device. B—Simple Priming and Aus
iliary Air Device. C—Coal Gas and Air Mixer. D—Method of Warming Carburetor. E-Emergency or Fuel Pipe.
Coal Gas for Testing Engines. The Willys-Overland Co., Toledo, Ohio, uses city gas for testing and running in engines in its testing department. The company has constructed a special mixer which fits the inlet manifold and takes the place of the carburetor. This is shown at Fig. 470, C. The housing is a cast iron cylinder having a threaded boss on one side for attaching to the gas supply at A. Level with the gas inlet are two air ports, B. B. Threaded into the bottom of the housing is a plug, the object of which is to rotate a sleeve immediately above it around in one direction or the other as may be required for the adjustment; this
sleeve is connected to the threaded plug by two sliding keys (not shown in drawing).
Running through the plug is a rod threaded at the upper end which permits of the sleeve being raised and lowered as may be required, but which will not rotate it on account of the sliding keys that move up and down in corresponding slots in the plug; the plug is locked in position by the screw, C. When setting the mixer in testing an engine, the sleeve is first rotated by the plug to obtain the correct proportion of gas and air, usually to a position as shown in section AA. Note that the gas supply is considerably smaller than the amount of air allowed. When this adjustment is made, the plug is locked by screw C. Then the speed of the motor can be regulated by raising or lowering the sleeve with the threaded rod running through the plug. This makes a very simple and inexpensive device which is entirely satisfactory. Besides saving fuel, it does away with the danger from split gasoline in the test shed.
Stopping Fuel Pipe Leaks.-One of the simplest emergency methods is to utilize a section of rubber tubing which is slipped over the metal pipe, but if the break be in the center of the line the vibration would tend to chafe the rubber. The latter should be braced by splints and the manner of attachment is shown at Fig. 470, E. Where this is not obtainable a repair may be made with ordinary friction tape. Strips of wood are laid lengthwise on a first winding of tape and in the same direction as the line and the outer tape wound as depicted at E 1, being tied with twine. The wrapping should be snug where the break occurs to prevent leakage of the fuel. A small crack may be treated in a similar manner or by using soap and tape as the former is not affected by gasoline; in fact, a piece of this material is invaluable in the tool kit. Shellac may also be used in conjunction with tire tape. A piece of rubber hose from the acetylene gas line may be used to join the broken pieces of tube temporarily.
Warming Manifold for Easy Starting.—One finds numerous instructions for easy starting of a gasoline engine under conditions of low temperature when the gasoline does not evaporate readily. Some ill advised writers have recommended the use of hot cloths