The Boy Mechanic Part 87

ordinary metal shelf brackets which were

[Ill.u.s.tration: Details of Motor]

screwed to a substantial wood base. This kept one-half of the casing independent of the main structure so that the wheel is easily accessible.

The nozzle was made of 1/2-in. bra.s.s pipe which was first filled with molten babbitt metal. When the metal was cool, a 1/4-in. hole was drilled halfway through the length of the tube, the hole being continued through to the other end by means of a 1/8-in. drill.

The lower orifice was then slightly enlarged with a small taper reamer, and the upper portion of the bore was reamed out almost to the bra.s.s to make a smooth entrance for the water.

A fixture to hold this nozzle is shown in Fig. 3. It was cast of babbitt metal in a wood mold. The hole for the nozzle was drilled at an angle of 20 deg. to the plate part. An alternative and perhaps easier way would be to insert the nozzle in the mold at the proper angle and cast the metal around it. A hole was then cut in one of the sides of the casing at a point 2-7/8 in. along a horizontal line from the center. The nozzle fixture was then bolted on with the exit orifice of the nozzle pointing downward and through the hole in the casing.

Six 1/8-in. holes were drilled through the flat portions of the rims while the two halves of the casing were held securely together in a vise. Bolts were used in these holes to join the casing.

The wheel was used on the dripboard of a kitchen sink and no provision was made to carry off the spent water except to cut two 1/2-in. holes in the bottom of the casing and allowing the waste to flow off directly into the sink.

--Contributed by Harry F. Lowe, Washington, D. C.

** Device for Baseball Throwing Practice [312]

Anyone training to be a baseball player will find the device shown in the accompanying ill.u.s.tration a great help

[Ill.u.s.tration: Ball Bounding on Concrete Slabs]

when practicing alone. It consists of two cement slabs, one flat and upright, the other curved and on the ground. The vertical slab is fastened securely against a fence, barn or shed. The barn or the shed is preferable, for if the slab is fastened to a fence, the ball will bound over a great many times and much time will be lost in finding it.

The player stands as far as he cares from the slabs and throws the ball against the lower slab. The ball immediately rebounds to the upright slab and returns with almost as great a force as it was delivered. If the thrower does not throw the ball exactly in the same spot each time, the ball will not rebound to the same place, consequently the eye and muscles are trained to act quickly, especially if the player stands within 15 or 20 ft. of the slabs and throws the ball with great force.

This apparatus also teaches a person to throw accurately, as a difference in aim of a few inches on the lower slab may cause the ball to flyaway over the player's head on the rebound.

--Contributed by F. L. Oilar, La Fayette, Indiana.

** How to Mail Photographs [312]

Cut a piece of cardboard 1 in. longer and 1 in. wider than the mount of the photograph and lay the picture on it in the center.

This allows a 1/2-in. border on all sides of the photograph. Punch two holes 1 in. apart at A, B, C and D, Fig. 1, in the cardboard border close to the edge of the picture. Put a string up through the hole B, Fig. 2, then across the corner of the photograph and down through the hole C and up through hole D, then to E, etc., until the starting point A is reached, and tie the ends.

The photograph will not get damaged, if it is covered with tissue paper and placed with the face to the cardboard. The extension border of cardboard prevents the edges of the mount from being damaged and the corners

[Ill.u.s.tration: Back for Mailing Photo]

from wearing. Both cardboard and photograph are wrapped together in paper, and the package is ready for mailing.

--Contributed by Earl R. Hastings, Corinth, Vt.

** A Mystifying Watch Trick [313]

Borrow a watch from one of the audience and allow the owner to place it in the box, as shown in Fig. 1. This box should be about 3 in. long, 4 in. wide and 2-1/2 in. deep, says the Scientific American. It should be provided with a hinged cover, M, with a lock, N. The tricky part of this box is the side S, which is pivoted at T by driving two short nails into it, one through the front side and the other through the back, so that when S is pushed in at the top, it swings around as shown in Fig. 1 and allows the watch to slide out into the performer's hand. The side S should fit tightly when closed, so that the box may be examined without betraying the secret. As the side S extends down to the bottom of the box, it facilitates the use of the fingers in pulling outward at the lower pan while the thumb is pressing inward at the top part. The side of the box opposite S should be built up in the same way, but not pivoted.

Use a flat-bottom tumbler, A, Fig. 2, containing an inner cone, B, for the reproduction of the watch. The cone is made of cardboard pasted together so it fits snugly inside of the tumbler. The cone is closed except at the bottom, then bran is pasted on the outside surfaces to make the tumbler appear as if filled with bran when it is in place. Place the tumbler with the cone inside on a table somewhat in the background. Put some loose bran on top of the cone and allow the cork, attached as shown in B, Fig. 2, to hang down on the outside of the tumbler, away from the audience. A large handkerchief should be laid beside the tumbler.

After the watch has been placed in the box, Fig. 1, the performer takes the box in his left hand, and while in the act of locking it with his right hand secures possession of the watch as previously explained. Tossing the key to the owner of the watch, the performer places the box on a chair or table near the audience and, with the watch securely palmed, walks back to get the tumbler. Standing directly in front of the tumbler with his back toward the audience, the performer

[Ill.u.s.tration: Parts for the Watch Trick]

quickly raises the cone with his right hand, lays the watch in the bottom of the tumbler and replaces the cone.

The loaded tumbler and the handkerchief are then brought forward, and the former is placed in full view of the audience with the cork hanging down behind it. The performer calls attention to the tumbler being full of bran and picks up some of it from the top to substantiate his statement. He then spreads the handkerchief over the tumbler, commands the watch to pa.s.s from the box into the tumbler and the bran to disappear.

The box is then handed to the owner of the watch so that he may unlock it with the key he holds. As soon as the box is found to be empty, the performer grasps the handkerchief spread over the tumbler, also the cork tied to the cone. Raising the handkerchief, he carries up the cone within it, leaving the watch in the bottom to be returned to its owner.

** Locking Several Drawers with One Lock [314]

A series or row of drawers can be secured with one lock by using the

[Ill.u.s.tration: Drawer Lock]

device shown in the sketch. This method takes away several dangling locks and the carrying of many keys. A rod is used through the various staples over the hasps. The rod is upset on one end and flattened to make sufficient metal for drilling a hole large enough to insert the bar of a padlock. If the bar is made of steel and hardened, it is almost impossible to cut it in two.

--Contributed by F. W. Bentley, Huron, S. Dak.

** Testing Small Electric Lamps [314]

The accompanying sketch shows the construction of a handy device for testing miniature electric lights. The base is made to take in an electric flash lamp battery. Two strips of bra.s.s, C and D, are connected to the battery. The lamp is tested by

[Ill.u.s.tration: Lamp Tester]

putting the metal end on the lower bra.s.s strip and the side against the upper one. A great number of lamps can be tested in a short time by means of this device.

--Contributed by Abner B. Shaw, North Dartmouth, Ma.s.s.

** How to Make a Pin Ball [314]

The pin ball shown in the ill.u.s.tration is made of calfskin modeling leather and saddler's felt. Two pieces of leather are used, and one piece of felt, all three being cut circular to a diameter of about 3 in. The felt may be about 1/2 in. thick, and leather of a deep brown color is recommended.

Moisten the leather on the back side with as much water as it will take without showing through the face. Lay it on a sheet of heavy gla.s.s or copper, or other hard, smooth, nonabsorbent material.

Place the design, which has been previously prepared, over the face of the leather. Indent the outline of the design with a nutpick or any other pointed tool that will not cut the leather.

Remove the pattern, and go

[Ill.u.s.tration: Made of Leather and Felt]

over the outline again to deepen the tool marks.

The s.p.a.ce between the border and the design is now stamped with a cuppointed nail set, care being taken not to cut the leather, especially if the tool be new. Rubbing the edges of the nail set over a piece of emery paper will serve to dull them, if they are too sharp.