Popular Science Monthly 



465 



Making Parallel Bars for the 

 Home Gymnasium 



AS no gymnasium is complete without 

 parallel bars, this plan of constructing 

 them may- prove interesting. It is of 

 simple construction, but as it is to be sub- 

 jected to rough handling, every joint must 

 be strong and rigid. Only the toughest 

 wood will do. Ash is 

 first choice, but maple, 

 oak, elm, hickory, or any 

 other straight-grained 

 hard wood will do. Every 

 piece must be carefully 

 smoothed with sand- 

 paper and 

 rubbed with 

 successive 

 coats of oil. Begin - 

 ning at the founda- 

 tion, choose three 

 planks that are flat 

 and true, without 

 warp or dip or curl. 

 The dimensions are 

 clearly shown in Fig. i. 

 To get the curve at the 

 ends of the shorter 

 planks uniform, cut a 

 paper pattern and use 

 it for the four 

 markings. Cut 

 to the marks 

 with a common 

 handsaw, but the narrower 

 the blade, the more con- 

 venient it will be. A 6-in. 

 groo\e is hollowed to the 

 depth of J/2-in. in the sides 



Assembled parts mak 

 ing the parallel bars 

 for the gymnasium 



of the base pieces, as shown. This gives 

 the base a better grip on the floor and 

 makes a handhold for lifting. 



The upright posts are 

 next in order of construc- 

 tion. They are 2^^ in. by 

 3 in. The joint used at 

 the base of the post is 

 shown in Fig. 2, and the 

 mortise at the top in 

 Fig. 3. Make the joints 

 tight, and have the posts 

 exactly vertical. The 

 tools necessary 

 are a brace 

 and bit, wood 

 chisel , saw, hammer and 

 sandpaper. The four 

 steel bar braces. Fig. 4, 

 may be procured from 

 a blacksmith. Wood 

 braces may be used 

 instead. Glue the bot- 

 tom of the post and 

 the sides of the socket 

 it fits into, and drive- a 

 couple of finishing nails 

 rough it into the 

 center plank. 

 The dimen- 

 sions of the 

 top tenon are 

 shown in Fig. 5 and Fig. 6. It is a 

 cross-section of bar and shows form, 

 thickness and width. If nails are 

 used to reinforce the glue joint, sink 

 the heads well below the surface. 

 A thorough smoothing and rubbing 

 with oil will complete the job. 



■I3i'^ 



6- .| 



A 



-r- 3 ■ 1 J 



54'- 



FIG I 



Owing to the rough handling of parallel bars it is necessary to have the parts made of tough 

 wood that is straight grained and put together with mortise and tenon joints and well oraced 



