Page:Popular Science Monthly Volume 91.djvu/945

 Making a Trusty Bob-Sled

Plans for the construction of a coasting bob-sled that will carry several persons

By B. Francis Dashiell

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���Rear sled

��THE bob-sled described and detailed in the accompanying plans is very strong and capable of carrying any weight that can be placed upon it. The powerful brake and steering apparatus will give a strong sense of security when coasting down even the steepest inclines.

The frame should be built first. This consists of two lengths of spruce, pine or oak, 2 by 3 in. and 13^ ft. in length. The various holes and notches are cut and bored in the required positions as shown. At the location of the steering wheel and front or guiding sled, oak boards 6 in. by 12 in. and 1 in. thick are bolted across, as shown.

The sleds are next con- structed. The rear sled is 24 in. long and 18 in. wide, the sides being of oak boards 10 in. wide and not less than iM in. in thickness. The edges are rounded off as shown. Three cross- pieces of oak are cut out 18 in. long and 8 in. wide and notched to receive the side pieces and also the two long frame pieces. The parts of the sled are joined together with long screws. The front or guiding sled is of the same width as the rear sled but is only 18 in. long and the sides are only 8 in. high. Four cross-pieces are used on this sled and are made of oak 18 in. long and 5 in. wide. They are screwed between the two sides in the same manner as those of the rear sled. The top of each cross-piece has a notch x /i in. deep and 6 in. wide cut in it to receive the 6 by 16-in. oak board as shown. Use screws for all fastenings.

The runners for the sleds are made from iron bars % in. by 1 in. and bent around the edges of the sled sides. Screws are placed on about 3-in. centers and have their heads countersunk in the run-

��Guiding sled'

���Ropes

��Plan and side elevation of a bob-sled that is capable of carrying any weight that can be placed on it

��ners. Smooth the iron well with a file, then polish with oil and emery cloth. Make two iron straps or U-rings and bolt to the rear of each side pie«e of the front sled as indicated in thie drawings. These are used to fasten the ends of the steering cables.

The brake is made from oak or pine 1 in. in thickness and is in the form of a box with the ends turned up or rounded off. The two side pieces are 6 in. wide and 18 in. long with the ends cut off at an angle of 45 deg. as shown. The bottom and ends are covered with i-in. boards, using screws for fastening them in place.

Get three angles 6 in. long, and bolt them to the bottom of the brake box as shown. The box is sus- pended be- tween and from the two long frame timbers by means of four swinging arms, each of oak 12 in. long, 2 in. wide and 1 in. thick. Make all the connections with bolts, using washers and lock nuts. Rivet over the ends of the bolts to prevent the nuts from working loose and coming off. The brake is operated with a lever of oak 28 in. long, 234 in. wide, and 1 in. thick. It is pivoted on a cross-support bearing made of a 12-in. length of %-in. wrought iron water pipe. Make two plates from sheet iron about 1/16 in. thick and bolt one on each side of the lever. A hole with a diameter of 1-3/32 in. should be cut in the plates and lever so that it will fit nicely on the pipe bearing. Drill the holes in the pipe support as called for in the plans and then place the lever over the pipe. The two ends should now be hammered down flat and drilled for the bolts. Place cotters in the holes, one on
 * ™^ i^-in. iron

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